JP2008031457A - Aliphatic-aromatic polyester and resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aliphatic-aromatic polyester improved in impact resistance, flexibility, resistance to heat decomposition, productivity, biodegradability and tear resistance. <P>SOLUTION: The aliphatic-aromatic polyester comprises an aliphatic dicarboxylic acid unit, an aromatic dicarboxylic acid unit and an aliphatic and/or alicyclic diol unit, and it further comprises a constituent unit having three or more ester-formable functional groups. The content of the constituent unit having the three or more functional groups capable of forming esters is 0.0001-4 mole% in the aliphatic-aromatic polyester. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an aliphatic aromatic polyester and a resin composition containing the aliphatic aromatic polyester. Specifically, the present invention relates to an aliphatic aromatic polyester having improved impact resistance, flexibility, thermal decomposition resistance, productivity, and biodegradability, and a resin composition containing the aliphatic aromatic polyester.

  In modern society, paper, plastic, aluminum foil, etc. are used in a wide range of applications such as liquids and powders for various foods, medicines, miscellaneous goods, packaging materials for solids, agricultural materials, and building materials. . In particular, plastics are excellent in strength, water resistance, moldability, transparency, cost, etc., and are used in many applications as bags and containers. Currently, plastics used for these applications include polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, and the like. However, the molded products made of the above plastics do not biodegrade or hydrolyze in the natural environment, or the degradation rate is extremely slow, so when they are buried after use, they remain in the soil or are discarded. In some cases, the landscape may be damaged. Moreover, even when incinerated, there are problems such as generating harmful gases and damaging the incinerator.

Therefore, as a means for solving the above-mentioned problems, many studies have been made on biodegradable materials. Typical examples of the biodegradable material include aliphatic polyester resins such as polylactic acid, polybutylene succinate, and polybutylene succinate adipate, and aromatic-aliphatic copolyester resins such as polybutylene adipate terephthalate. On the other hand, Patent Literature 1 and Patent Literature 2 have been proposed as aliphatic aromatic polyesters having biodegradability.
JP 2005-525448 A Japanese Patent No. 3411289

  Since the aliphatic aromatic polyester disclosed in Patent Document 1 has a slow biodegradation rate, it is essential to contain a sulfonate group in the dicarboxylic acid component, which is disadvantageous in terms of cost and production. There was a point. In addition, since the aliphatic aromatic polyester disclosed in Patent Document 2 uses adipic acid or a derivative thereof as an essential component as a dicarboxylic acid, the thermal stability during polymerization is deteriorated, and the thermal decomposition temperature of the polymer is reduced. There was a problem. Further, since it is difficult to obtain a sufficient molecular weight, it is necessary to separately polymerize a relatively low molecular weight polyester and then separately perform a high molecular weight reaction by a second-stage reaction.

  The present invention solves the above-mentioned problems of the prior art, an aliphatic aromatic polyester having improved impact resistance, flexibility, thermal decomposition resistance, productivity, biodegradability, and tear resistance, and the aliphatic aromatic polyester. It aims at providing the resin composition containing a group polyester.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have made aliphatic biopolyester contain a constituent unit having a tri- or higher functional ester-forming group at a predetermined ratio. The inventors have found that impact resistance, flexibility, thermal decomposition resistance, productivity, and tear resistance can be improved while maintaining the decomposability characteristics, and the present invention has been completed.

  That is, the first gist of the present invention is an aliphatic aromatic polyester containing at least an aliphatic dicarboxylic acid unit, an aromatic dicarboxylic acid unit, and an aliphatic and / or alicyclic diol unit, and further comprising a trifunctional group. The content ratio of the structural unit having an ester-forming group having three or more functional groups in the aliphatic aromatic polyester including the structural unit having the ester-forming group described above is based on the total of all the structural units of the aliphatic aromatic polyester It is an aliphatic aromatic polyester characterized by being 0.0001 to 4 mol%.

  The second gist of the present invention is characterized in that the molar ratio of the aliphatic dicarboxylic acid unit to the aromatic dicarboxylic acid unit is aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit = 10/90 to 90/10. The aliphatic aromatic polyester according to claim 1.

  According to a third aspect of the present invention, the aliphatic dicarboxylic acid unit contains at least succinic acid, and the terephthalic acid and / or isophthalic acid unit is contained as the aromatic dicarboxylic acid unit. The aliphatic aromatic polyester described.

  The fourth gist of the present invention further includes a hydroxycarboxylic acid unit, and the content ratio of the hydroxycarboxylic acid unit in the aliphatic aromatic polyester is 0.01 to the total of all the structural units of the aliphatic aromatic polyester. It exists in the aliphatic aromatic polyester of any one of Claim 1 thru | or 3 characterized by the above-mentioned.

  The fifth gist of the present invention resides in the aliphatic aromatic polyester according to any one of claims 1 to 4, which has a tensile modulus of 300 MPa or less.

  The sixth gist of the present invention is a polyester containing an aliphatic and / or alicyclic diol unit and an aliphatic and / or alicyclic dicarboxylic acid unit as constituent units (excluding an aromatic dicarboxylic acid unit). And an aliphatic aromatic polyester according to any one of claims 1 to 5.

  The seventh gist of the present invention resides in a resin composition comprising a polylactic acid-based aliphatic polyester and the aliphatic aromatic polyester according to any one of claims 1 to 5. .

  The eighth gist of the present invention resides in a film formed by molding a resin composition containing at least the aliphatic aromatic polyester according to any one of claims 1 to 5.

  The ninth gist of the present invention resides in a sheet formed by molding a resin composition containing at least the aliphatic aromatic polyester according to any one of claims 1 to 5.

  The tenth gist of the present invention resides in a herbicidal sheet obtained by molding a resin composition containing at least the aliphatic aromatic polyester according to any one of claims 1 to 5.

  According to the present invention, an aliphatic aromatic polyester having improved impact resistance, flexibility, thermal decomposition resistance, productivity, biodegradability, and tear resistance, and a resin composition containing the aliphatic aromatic polyester are provided. Provided.

  Hereinafter, embodiments of the aliphatic aromatic polyester of the present invention and a resin composition containing the same will be described in detail.

<Aliphatic aromatic polyester>
The polyester of the present invention includes an aliphatic dicarboxylic acid unit, an aromatic dicarboxylic acid unit, an aliphatic and / or alicyclic diol unit, and a structural unit having a tri- or more functional ester-forming group, The content ratio of the structural unit having a trifunctional or higher functional ester-forming group in the group polyester is 0.0001 to 4 mol%.

  The dicarboxylic acid component for constituting the dicarboxylic acid unit includes an aliphatic dicarboxylic acid or a derivative thereof (hereinafter sometimes referred to as “aliphatic dicarboxylic acid component”) and an aromatic dicarboxylic acid or a derivative thereof (hereinafter referred to as “aromatic”. May be referred to as "dicarboxylic acid component"). Moreover, as a diol component for comprising a diol unit, an aliphatic and / or alicyclic diol component is used, and further, a component containing a trifunctional or higher functional ester-forming group is included. In addition, the component said by this invention means the raw material used as the unit contained in a copolymer.

  Moreover, the monomer which comprises these aliphatic aromatic polyesters may be a component derived from biomass resources.

The ratio of the aliphatic dicarboxylic acid unit and the aromatic dicarboxylic acid unit constituting the dicarboxylic acid unit of the polyester of the present invention is preferably 10 mol% at the lower limit as the ratio of the aliphatic dicarboxylic acid unit to the total thereof. More preferably, it is 30 mol%. Moreover, a preferable upper limit is 90 mol%, More preferably, it is 80 mol%. That is, the molar ratio of the aliphatic dicarboxylic acid unit to the aromatic dicarboxylic acid unit in the aliphatic aromatic polyester is preferably aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit = 10/90 to 90/10, more preferably The amount is 30/70 to 80/20.
The ratio of the aliphatic dicarboxylic acid unit and the aromatic dicarboxylic acid unit is approximately equal to the ratio of the aliphatic dicarboxylic acid component and the aromatic dicarboxylic acid component, respectively.

  If the ratio of the aliphatic dicarboxylic acid unit is less than the above lower limit and the number of aromatic dicarboxylic acid unit positions is large, the biodegradability of the aliphatic aromatic polyester is impaired and the flexibility is insufficient. Moreover, when the ratio of an aliphatic dicarboxylic acid unit is larger than the said upper limit and there are few aromatic dicarboxylic acid units, biodegradation speed | velocity is too quick, thermal decomposition temperature falls and it is unpreferable, and a softness | flexibility is also insufficient. That is, the aliphatic aromatic polyester exhibits excellent flexibility when the ratio of the aliphatic dicarboxylic acid unit and the ratio of the aromatic dicarboxylic acid unit are the above-mentioned specific ratio.

(1) Aliphatic dicarboxylic acid unit Specific examples of the aliphatic dicarboxylic acid component constituting the aliphatic dicarboxylic acid unit of the aliphatic aromatic polyester include oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, and dodecanedi Examples thereof include acid and 1,6-cyclohexanedicarboxylic acid. These may be acid anhydrides. Examples of the aliphatic dicarboxylic acid derivatives include lower alkyl esters of these aliphatic dicarboxylic acids. Among these, succinic acid, glutaric acid, sebacic acid, dimer acid and dodecanedioic acid, and their lower alkyl (for example, alkyl having 1 to 4 carbon atoms) ester derivatives are preferable, and in particular, lower succinic acid and succinic acid. Alkyl ester derivatives or mixtures thereof are preferred. These may be used individually by 1 type, and may mix and use 2 or more types.

(2) Aromatic dicarboxylic acid unit Specific examples of the aromatic dicarboxylic acid component constituting the aromatic dicarboxylic acid unit include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, and diphenyldicarboxylic acid. These may be acid anhydrides. Examples of the aromatic dicarboxylic acid derivatives include lower alkyl esters of these aromatic dicarboxylic acids. Among these, terephthalic acid, isophthalic acid, or their lower alkyl (e.g., alkyl having 1 to 4 carbon atoms) ester derivatives are preferable, and in particular, terephthalic acid and / or methyl ester of terephthalic acid, terephthalic acid and / or terephthalic acid. A mixture containing a methyl ester of an acid and isophthalic acid and / or a methyl ester of isophthalic acid is preferred. These may be used individually by 1 type, and may mix and use 2 or more types.
When the aromatic dicarboxylic acid component is a mixture containing terephthalic acid and / or methyl ester of terephthalic acid and methyl ester of isophthalic acid and / or isophthalic acid, the isophthalic acid unit is added to the total of the aromatic dicarboxylic acid units. On the other hand, the lower limit is preferably 5 mol% and the upper limit is preferably 25 mol%. If the isophthalic acid unit is less than this lower limit, a sufficiently flexible resin cannot be obtained, and if it exceeds the upper limit, the price of the resin is increased, which is not preferable.

(3) Aliphatic and / or alicyclic diol unit As the aliphatic and / or alicyclic diol component constituting the aliphatic and / or alicyclic diol unit, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol Can be mentioned. Of these, 1,4-butanediol, ethylene glycol and 1,3-propanediol are preferred from the viewpoint of the physical properties of the resulting aliphatic aromatic polyester, and 1,4-butanediol and / or ethylene glycol are particularly preferred. preferable. These may be used individually by 1 type, and may mix and use 2 or more types.

  The content ratio of the aliphatic and / or alicyclic diol units in the aliphatic aromatic polyester is usually substantially equimolar to the sum of the aliphatic dicarboxylic acid units and the aromatic dicarboxylic acid units.

(4) Constituent unit having trifunctional or higher ester-forming group The compound constituting the structural unit having trifunctional or higher ester-forming group is a trifunctional or higher polyhydric alcohol; Or at least one trifunctional or higher polyfunctional compound selected from the group consisting of: an anhydride, an acid chloride, an ester thereof; and a tri- or higher functional hydroxycarboxylic acid or an anhydride thereof, an acid chloride, an ester; It is done.

  Specific examples of the trifunctional or higher polyhydric alcohol include glycerin, trimethylolpropane, pentaerythritol and the like. These may be used individually by 1 type, and may mix and use 2 or more types.

  Specific examples of the trifunctional or higher polyvalent carboxylic acid or anhydride thereof include trimesic acid, propanetricarboxylic acid, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, cyclopentatetracarboxylic anhydride Thing etc. are mentioned. These may be used individually by 1 type, and may mix and use 2 or more types.

  Specific examples of the tri- or higher functional hydroxycarboxylic acid include malic acid, hydroxyglutaric acid, hydroxymethylglutaric acid, tartaric acid, citric acid, hydroxyisophthalic acid, and hydroxyterephthalic acid. These may be used individually by 1 type, and may mix and use 2 or more types.

  Of these, malic acid, tartaric acid, and citric acid are particularly preferred because of their availability.

  The content ratio of the structural unit having a trifunctional or higher functional ester-forming group is 0.0001 mol% in total, preferably 0 with respect to the total of all the structural units constituting the aliphatic aromatic polyester of the present invention. 0.001 mol%, more preferably 0.005 mol%, and most preferably 0.01 mol%. The upper limit is 4 mol%, preferably 3 mol%, and most preferably 1 mol%. When the content ratio of the structural unit having a trifunctional or higher functional ester-forming group in the aliphatic aromatic polyester is larger than the above upper limit, the crosslinking of the polymer proceeds excessively, and the strand cannot be stably extracted. Problems such as deterioration and damage to various physical properties occur, which is not preferable. In addition, if the content of the structural unit having a trifunctional or higher functional ester-forming group in the aliphatic aromatic polyester is less than the above lower limit, the raw material is excessively loaded and the cost is increased, and the reactivity of the polymerization reaction is increased. This is not preferable.

(5) Other structural units The aliphatic aromatic polyester of the present invention may contain a hydroxycarboxylic acid unit in addition to the above structural units. The hydroxycarboxylic acid and the hydroxycarboxylic acid derivative constituting the hydroxycarboxylic acid unit (hereinafter sometimes referred to as “hydroxycarboxylic acid component”) include a compound having one hydroxyl group and a carboxyl group in the molecule or a derivative thereof. There is no particular limitation as long as it is present. Specific examples of hydroxycarboxylic acid and its derivatives include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, 2-hydroxy3,3-dimethylbutyric acid, 2-hydroxy Examples include -3-methylbutyric acid and 2-hydroxyisocaproic acid, mandelic acid, salicylic acid, and esters, acid chlorides, and acid anhydrides thereof. These may be used individually by 1 type, and may mix and use 2 or more types. Moreover, when optical isomers exist in these, any of D-form, L-form, or a racemate may be sufficient, and a form may be a solid, a liquid, or aqueous solution.

  Of these, particularly preferred are lactic acid and / or glycolic acid and caprolactone, which are remarkably increased in the polymerization rate during use and are readily available, and most preferred is lactic acid. As these forms, a 30 to 95% by weight aqueous solution is preferable because it can be easily obtained.

  The upper limit of the content ratio of the hydroxycarboxylic acid unit is 50 mol%, preferably 30 mol%, most preferably 20 mol%, based on the total of all the structural units constituting the aliphatic aromatic polyester of the present invention. . When the content ratio of the hydroxycarboxylic acid unit in the aliphatic aromatic polyester is larger than the above upper limit, the mechanical properties are lowered, and the volatile matter is increased in production, which causes a problem.

  In the present invention, in order to increase the hydrophilicity of the aliphatic aromatic polyester, a compound having a hydrophilic group such as a sulfone group, a phosphoric acid group, an amino group, or a nitric acid group is used at the time of production. May be introduced. Examples of the compound for this purpose include 4-sulfonated-2,6-isophthalic acid. In addition, chain extenders such as diisocyanate, diphenyl carbonate, dioxazoline, and silicate ester may be used. In particular, when a carbonate compound such as diphenyl carbonate is used, diphenyl carbonate is an all component of the aliphatic aromatic polyester. It is also preferable to obtain polyester carbonate by adding 20 mol% or less, preferably 10 mol% or less, based on

  In this case, as the carbonate compound, specifically, diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, ethylene carbonate, diamyl Examples include carbonate and dicyclohexyl carbonate. In addition, carbonate compounds composed of the same or different hydroxy compounds derived from hydroxy compounds such as phenols and alcohols can also be used.

  Specific examples of the diisocyanate compound include 2,4-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, and 1,5-naphthylene diisocyanate. And known diisocyanates such as xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

  Specific examples of the silicate ester include tetramethoxysilane, dimethoxydiphenylsilane, dimethoxydimethylsilane, and diphenyldihydroxylane.

  In order to increase the melt tension, a small amount of peroxide may be added.

  Any of these may be used alone or in combination of two or more.

  In the present invention, the polyester terminal group of the aliphatic aromatic polyester may be sealed with carbodiimide, an epoxy compound, a monofunctional alcohol or carboxylic acid. Degradability can be further improved.

  In this case, examples of the carbodiimide compound include compounds having one or more carbodiimide groups in the molecule (including polycarbodiimide compounds). Specifically, as the monocarbodiimide compound, dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, Examples thereof include diisobutyl carbodiimide, dioctyl carbodiimide, t-butyl isopropyl carbodiimide, diphenyl carbodiimide, di-t-butyl carbodiimide, di-β-naphthyl carbodiimide, N, N′-di-2,6-diisopropylphenyl carbodiimide. These may be used individually by 1 type, and may mix and use 2 or more types.

(6) Other components In the aliphatic aromatic polyester of the present invention, various additives such as a heat stabilizer, an antioxidant, a hydrolysis inhibitor, a crystal nucleating agent, a difficulty, as long as the characteristics are not impaired. A flame retardant, an antistatic agent, a release agent, an ultraviolet absorber, or the like may be added.

  These additives may be added to the reaction apparatus before the polymerization reaction, may be added to the conveying apparatus from the start of the polymerization reaction to the end of the polymerization reaction, or after the completion of the polymerization reaction, before the product is withdrawn. It may be added. Moreover, you may add to the polyester after extraction.

When molding the aliphatic aromatic polyester of the present invention, in addition to the various additives shown above, reinforcing agents such as glass fiber, carbon fiber, titanium whisker, mica, talc, CaCO ₃ , TiO ₂ and silica Further, it may be molded by adding a bulking agent or the like.

<Method for producing aliphatic aromatic polyester>
As the method for producing the aliphatic aromatic polyester of the present invention, known methods relating to the production of polyester can be employed. Moreover, the polycondensation reaction in this case can set the appropriate conditions conventionally employ | adopted, and is not restrict | limited in particular. After the esterification reaction proceeds, the degree of polymerization can be further increased by performing a pressure reduction operation.

  The amount of the aliphatic and / or alicyclic diol used is substantially equimolar with respect to the total number of moles of the aliphatic dicarboxylic acid component and aromatic dicarboxylic acid component. In view of the presence, it is used in excess of 1 to 100 mol%, preferably 5 to 80 mol%, more preferably 10 to 60 mol%.

  The addition time of the trifunctional or higher polyfunctional compound may be any before the other raw materials are charged, at the time of charging, after the charging, before the polymerization reaction, between the start of the polymerization reaction and the end of the reaction. It is preferable to charge at the same time from the viewpoint of simplification of the process.

Moreover, when using a hydroxycarboxylic acid component, the addition timing and method of the hydroxycarboxylic acid component are not particularly limited as long as they are before the end of the polycondensation reaction.
(1) A method of adding a catalyst in a state dissolved in a hydroxycarboxylic acid solution in advance,
(2) A method of adding the catalyst at the same time as adding the catalyst when charging the raw materials,
Etc.

  The aliphatic aromatic polyester of the present invention is produced in the presence of a catalyst. As the catalyst, any catalyst that can be used for the production of polyester can be selected, but germanium, titanium, zirconium, hafnium, antimony, tin, magnesium, calcium, zinc, aluminum, cobalt, lead, cesium, manganese Metal compounds such as lithium, potassium, sodium, copper, barium and cadmium are preferred. Of these, germanium compounds, titanium compounds, magnesium compounds, zinc compounds, and lead compounds are preferable, and titanium compounds and magnesium compounds are particularly preferable.

  The titanium compound is not particularly limited, and preferred examples include organic titanium compounds such as tetraalkoxytitanium such as tetrapropyl titanate, tetrabutyl titanate, tetraethyl titanate, tetrahydroxyethyl titanate, and tetraphenyl titanate. Among these, tetrapropyl titanate, tetrabutyl titanate, and the like are preferable from the viewpoint of price and availability, and the most preferable catalyst is tetrabutyl titanate.

  As the magnesium compound, magnesium formate, magnesium acetate, magnesium propionate, magnesium n-butyrate, magnesium n-valerate, magnesium n-caproate, magnesium n-caprate, magnesium stearate, magnesium oxide, etc. are preferred. Preferably, magnesium formate, magnesium acetate, magnesium propionate, and more preferably magnesium acetate is used.

  These catalysts may be used individually by 1 type, and may mix and use 2 or more types. Moreover, unless the objective of this invention is impaired, combined use of another catalyst is not prevented.

  As the catalyst, a combination of tetraalkoxy titanium and a magnesium compound is particularly preferable because of high activity, and a combination of tetrabutyl titanate and magnesium acetate is most preferable.

  The amount of the catalyst used is a metal equivalent amount in the catalyst with respect to the amount of monomer used for the reaction, and the lower limit is preferably 0.0001% by weight, more preferably 0.001% by weight, still more preferably 0.003% by weight. is there. The upper limit is preferably 3% by weight, more preferably 1% by weight, still more preferably 0.1% by weight, and most preferably 0.05% by weight. If the amount of the catalyst used is less than the above lower limit, the reaction rate of the polymerization reaction is too slow, which is not preferable for production, and if it exceeds the above upper limit, the production cost becomes too high, and the stability of the polyester from which the catalyst residue is obtained is increased. It has an adverse effect and is not preferred.

  The addition timing of the catalyst is not particularly limited as long as it is before the start of the pressure reduction reaction, and may be added at the time of charging the raw material or may be added at the start of pressure reduction.

Regarding the conditions such as the reaction temperature, polymerization time, and pressure when producing the aliphatic aromatic polyester of the present invention, the temperature is 150 to 260 ° C., preferably 180 to 250 ° C., and the polymerization time is It is good to select in the range of 1 hour or more, preferably 4 to 15 hours. The pressure is preferably selected under the condition that the final degree of decompression is 1.33 × 10 ³ Pa or less, more preferably 0.27 × 10 ³ Pa or less.

<Physical properties of aliphatic aromatic polyester>
The aliphatic aromatic polyester of the present invention has the following characteristics.

  The preferred reduced viscosity (ηsp / c) of the aliphatic aromatic polyester of the present invention is 1.2 or more, more preferably 1.4 or more, and most preferably 1.6 or more. The upper limit of the reduced viscosity (ηsp / c) of the aliphatic aromatic polyester is usually 4.0, preferably 3.0, and more preferably 2.5. If the reduced viscosity is less than 1.2, the mechanical properties are undesirably lowered, and if it exceeds 4.0, molding becomes difficult.

  The reduced viscosity (ηsp / c) of the aliphatic aromatic polyester was a solution measured at 30 ° C. in phenol / tetrachloroethane (1: 1 weight ratio) at an aliphatic aromatic polyester concentration of 0.5 dl / g. It is obtained from the viscosity.

  Further, the tensile elastic modulus of the aliphatic aromatic polyester of the present invention is preferably 300 MPa or less, more preferably 200 MPa or less. If the tensile modulus is greater than 300 MPa, sufficient impact resistance and flexibility cannot be obtained, which is not preferable.

  The tensile elastic modulus of the aliphatic aromatic polyester is an initial elastic modulus in a tensile test of a sample film obtained by molding the aliphatic aromatic polyester, and will be described in detail in the Examples section below. Measured by the method.

<Resin composition>
(1) Resin Composition with Aliphatic Polyester The aliphatic aromatic polyester of the present invention comprises an aliphatic and / or alicyclic diol unit and an aliphatic and / or alicyclic dicarboxylic acid unit as constituent units (however, aromatic It can be used as a resin composition with various aliphatic polyesters such as an aliphatic polyester containing an aliphatic dicarboxylic acid unit and a polylactic acid aliphatic polyester containing a lactic acid unit as a constituent unit.

  Below, the aliphatic polyester suitably used by mixing with the aliphatic aromatic polyester of the present invention will be described.

(I) Aliphatic polyester comprising diol / dicarboxylic acid As the aliphatic polyester that can be used by mixing with the aliphatic aromatic polyester of the present invention, aliphatic and / or alicyclic diol units and aliphatic and / or Aliphatic polyester-based resins containing alicyclic dicarboxylic acid units as essential components can be mentioned.

  Specific examples of the aliphatic and / or alicyclic diol unit constituting the aliphatic polyester resin include, for example, an ethylene glycol unit, a diethylene glycol unit, a triethylene glycol unit, a polyethylene glycol unit, a propylene glycol unit, and a dipropylene glycol. Unit, 1,3-butanediol unit, 1,4-butanediol unit, 3-methyl-1,5-pentanediol unit, 1,6-hexanediol unit, 1,9-nonanediol unit, neopentyl A glycol unit, a polytetramethylene glycol unit, a 1,4-cyclohexanedimethanol unit, etc. are mentioned. These may be used individually by 1 type, and may mix and use 2 or more types.

  Specific examples of the aliphatic and / or alicyclic dicarboxylic acid units constituting the aliphatic and / or alicyclic polyester-based resin include, for example, succinic acid units, oxalic acid units, malonic acid units, glutaric acid units, Examples include an adipic acid unit, a pimelic acid unit, a suberic acid unit, an azelaic acid unit, a sebacic acid unit, an undecanedioic acid unit, a dodecanedioic acid unit, and a 1,4-cyclohexanedicarboxylic acid unit. These may be used individually by 1 type, and may mix and use 2 or more types.

  The aliphatic polyester-based resin includes a lactic acid unit, a hydroxycarboxylic acid unit such as a 6-hydroxycaproic acid unit, a trimethylolpropane unit, a glycerin unit, a pentaerythritol unit, a propanetricarboxylic acid unit, a malic acid unit, a citric acid unit, A trifunctional or higher functional aliphatic polyhydric alcohol unit such as a tartaric acid unit, an aliphatic polyvalent carboxylic acid unit, and an aliphatic polyvalent oxycarboxylic acid unit may be copolymerized.

  The diol (polyhydric alcohol) unit, dicarboxylic acid (polycarboxylic acid) unit, and hydroxycarboxylic acid unit constituting the aliphatic polyester resin are mainly aliphatic, but do not impair biodegradability. Within a range, a small amount of other components, for example, aromatic compound units such as aromatic diol (polyhydric alcohol) units and aromatic hydroxycarboxylic acid units may be contained. Specific examples of the aromatic diol (polyhydric alcohol) unit include a bisphenol A unit and a 1,4-benzenedimethanol unit. Specific examples of the aromatic hydroxycarboxylic acid unit include a hydroxybenzoic acid unit.

  In addition, a urethane bond, an amide bond, a carbonate bond, an ether bond, a ketone bond, or the like may be introduced into the aliphatic polyester resin within a range that does not affect biodegradability.

  Moreover, as an aliphatic polyester-type resin, you may use the thing which raised the molecular weight, for example using the isocyanate compound, the epoxy compound, the oxazoline compound, the acid anhydride, the peroxide, or bridge | crosslinked. Furthermore, the terminal group may be sealed with carbodiimide, epoxy compound, monofunctional alcohol or carboxylic acid.

(Ii) Polylactic acid-based aliphatic polyester containing a lactic acid unit As an example of the aliphatic polyester that can be used by mixing with the aliphatic aromatic polyester of the present invention, polylactic acid-based polyester can be mentioned. Specific examples of units constituting this polylactic acid-based aliphatic polyester include, in addition to lactic acid units, for example, glycolic acid units, 3-hydroxybutyric acid units, 4-hydroxybutyric acid units, 4-hydroxyvaleric acid units, 5- Examples thereof include hydroxyvaleric acid units and 6-hydroxycaproic acid units. Moreover, as a lactic acid unit, L-lactic acid is preferable in terms of availability and physical properties. The polylactic acid-based aliphatic polyester may be composed of lactic acid units alone or may be composed of units other than lactic acid units. Further, the polylactic acid aliphatic polyester usually contains 50 mol% or more of lactic acid units in the constituent units.

  Polylactic acid-based aliphatic polyesters include aliphatic and / or alicyclic diol units such as 1,4-butanediol units, succinic acid units, and adipic acid units, and aliphatic and / or alicyclic dicarboxylic acid units, Methylolpropane units, glycerin units, pentaerythritol units, propanetricarboxylic acid units, malic acid units, citric acid units, tartaric acid units and other trifunctional or higher aliphatic polyhydric alcohol units, aliphatic polycarboxylic acid units, aliphatic polyhydric units Divalent hydroxycarboxylic acid units may be copolymerized.

(2) Mixing ratio When the aliphatic polyester or polylactic acid aliphatic polyester composed of the diol / dicarboxylic acid as described above is mixed with the aliphatic aromatic polyester of the present invention and used as a resin composition, the aliphatic of the present invention. Although there is no restriction | limiting in particular in the usage-amount of aromatic polyester and these other polyesters, For example, it uses in the range of the aliphatic aromatic polyester of this invention: other polyester = 1: 99-99: 1 (weight ratio). be able to. The mixing ratio is preferably 5:95 to 5:95, more preferably 10:90 to 90:10. If the mixing ratio of the aliphatic aromatic polyester in the resin composition is too large, the crystallization speed at the time of molding tends to be slow, and the productivity tends to be impaired, and if too small, the thermal decomposition resistance, impact resistance, Flexibility tends to be impaired.

(3) Other components Various conventionally well-known additives can be mix | blended with the resin composition of this invention.

Examples of additives include crystal nucleating agents, antioxidants, anti-blocking agents, ultraviolet absorbers, light-resistant agents, plasticizers, heat stabilizers, colorants, flame retardants, mold release agents, antistatic agents, and antifogging agents. And additives for resins such as surface wetting improvers, incineration aids, pigments, lubricants, dispersion aids and various surfactants. These may be used individually by 1 type, and may mix and use 2 or more types.
In particular, additives such as lubricants, mold release agents, crystal nucleating agents, antioxidants, anti-blocking agents, ultraviolet absorbers, light-proofing agents, and coloring agents are used when used for herbicidal sheets and agricultural films. Good.

  Moreover, a chemical fertilizer, a soil conditioner, a plant activator, etc. can also be mix | blended with the resin composition of this invention as a conventionally well-known various filler and a functional additive.

  The filler is roughly classified into an inorganic filler and an organic filler.

  Examples of inorganic fillers include anhydrous silica, mica, talc, titanium oxide, calcium carbonate, diatomaceous earth, allophane, bentonite, potassium titanate, zeolite, sepiolite, smectite, kaolin, kaolinite, glass, limestone, carbon, wallastenite. , Calcinated perlite, silicates such as calcium silicate and sodium silicate, hydroxides such as aluminum oxide, magnesium carbonate and calcium hydroxide, salts such as ferric carbonate, zinc oxide, iron oxide, aluminum phosphate and barium sulfate Is mentioned. These may be used individually by 1 type, and may mix and use 2 or more types.

  The content of the inorganic filler in the resin composition is usually 1 to 80% by weight, preferably 3 to 70% by weight, and more preferably 5 to 60% by weight.

  Some inorganic fillers, such as calcium carbonate and limestone, have properties of soil improvers. If a resin composition containing a large amount of these inorganic fillers is dumped in the soil, the resin composition The inorganic filler after biodegradation of this remains and functions as a soil conditioner. In the case of applications such as agricultural materials and civil engineering materials that are dumped in the soil, it is the present invention that polyesters added with chemical fertilizers, soil conditioners, plant activators, etc. are used as molded articles. Will increase the usefulness of polyester.

  Examples of the organic filler include raw starch, processed starch, chitin / chitosan powder, and wood powder (including pulp, coconut shell powder, bamboo powder, bark powder, kenaf and straw). These may be used individually by 1 type, and may mix and use 2 or more types.

  The content of the organic filler in the resin composition is usually preferably 1 to 50% by weight and particularly preferably 20 to 40% by weight. When the resin composition containing these organic fillers is dumped in the soil, after the resin biodegradation, depending on the type of the organic filler, the organic filler remains in the soil and functions as a soil conditioner and compost. It becomes like this.

(4) Kneading method In the preparation of the resin composition of the present invention, all conventionally known mixing / kneading techniques can be applied.

  As the mixer, a horizontal cylindrical type, V-shaped, double-cone type mixer, a blender such as a ribbon blender or a super mixer, various continuous mixers, or the like can be used. Moreover, as a kneading machine, a batch type kneading machine such as a roll or an internal mixer, a one-stage type, a two-stage type continuous kneading machine, a twin screw extruder, a single screw extruder, or the like can be used.

  Examples of the kneading method include a method in which various additives, fillers, other polyesters, etc. are added and blended when the aliphatic aromatic polyester and / or other polyester of the present invention is heated and melted.

  At this time, blending oil or the like can be used for the purpose of uniformly dispersing the various additives.

(5) Molding method The aliphatic aromatic polyester and resin composition of the present invention can be subjected to molding by various molding methods applied to general-purpose plastics.

  Examples of the molding method include compression molding (compression molding, laminate molding, stampable molding), injection molding, extrusion molding, and coextrusion molding (film molding by inflation method and T-die method, laminate molding, pipe molding, electric wire / cable molding. , Profile molding), hollow molding (various blow molding), calendar molding, foam molding (melt foam molding, solid phase foam molding), solid molding (uniaxial stretching molding, biaxial stretching molding, roll rolling molding, stretch oriented nonwoven fabric Examples thereof include molding, thermoforming (vacuum forming, pressure forming), plastic working), powder forming (rotary forming), various non-woven fabric forming (dry method, adhesion method, entanglement method, spunbond method, etc.).

  The aliphatic aromatic polyester and resin composition of the present invention are preferably applied to films, containers, and fibers, particularly as injection-molded articles, foam-molded articles, and hollow molded articles.

  Also, these molded products are provided with chemical functions, electrical functions, magnetic functions, mechanical functions, friction / wear / lubricating functions, optical functions, thermal functions, surface functions such as biocompatibility, etc. For this purpose, it is also possible to perform various purposeful secondary processing. Examples of secondary processing include embossing, painting, adhesion, printing, metalizing (plating, etc.), machining, surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, Coating, etc.).

<Application>
The aliphatic aromatic polyester and resin composition of the present invention are suitable for use in various film applications and injection-molded product applications.

  Applications include injection molded products (for example, fresh food trays, fast food containers, outdoor leisure products, etc.), extruded products (films, such as fishing lines, fishing nets, vegetation nets, water retaining sheets, etc.), hollow molded products ( And other agricultural films, coating materials, fertilizer coating materials, laminate films, plates, stretched sheets, monofilaments, non-woven fabrics, flat yarns, staples, crimped fibers, striped tapes, split yarns , Composite fiber, blow bottle, foam, shopping bag, garbage bag, compost bag, cosmetic container, detergent container, bleach container, rope, binding material, sanitary cover stock material, cold box, cushion material film, multifilament, Synthetic paper, surgical thread, suture thread, artificial bone, artificial skin, my Examples thereof include DDS such as black capsules and wound dressings. In addition, information electronic materials such as toner binders and thermal transfer ink binders, automotive interior parts such as electrical product casings, instrument panels, sheets, and pillars, and automotive parts such as automotive exterior structural materials such as bumpers, front grills, and wheel covers. Can be used. More preferably, packaging materials such as packaging films, bags, trays, bottles, cushioning foams, fish boxes, etc., and agricultural materials such as mulching films, tunnel films, house films, sun coverings, grass protections. Sheets (including cocoon sheets, germination sheets, vegetation mats, etc.), nursery beds, flower pots, etc.

<Film, sheet>
When the aliphatic aromatic polyester or resin composition of the present invention is used as a film or sheet, the production method thereof includes a normal melt molding method of a thermoplastic resin, for example, inflation molding, extrusion molding, compression molding, vacuum molding, Injection molding, hollow molding, rotational molding, etc., as well as methods that apply secondary molding methods such as thermoforming, stretch molding, foam molding, etc., can be applied to them, especially in film molding, especially inflation molding, injection Molding is preferred, and sheet molding is preferably calendar molding or T-die extrusion molding.
In the present invention, a film having a thickness of less than 200 μm is defined as a film, and a sheet having a thickness of 200 μm or more is defined as a sheet.

  When the aliphatic aromatic polyester of the present invention is used as a film or sheet, the aliphatic aromatic polyester of the present invention is a polycondensate of the above-mentioned aliphatic or alicyclic diol and an aliphatic or alicyclic dicarboxylic acid, and Copolycondensates, polycondensates and copolycondensates of hydroxycarboxylic acids, polycondensates and copolycondensates of lactones, and diols and dicarboxylic acids, and copolycondensates such as lactones and hydroxycarboxylic acids Etc., preferably formed as a resin composition kneaded with polybutylene succinate or polylactic acid, whereby the film or sheet can be improved in performance such as breaking strength, breaking elongation, tear strength, etc. .

  In this case, the mixing ratio between the aliphatic aromatic polyester of the present invention and other polyesters such as polybutylene succinate and polylactic acid is sufficient to improve the above performance by blending the other polyester when it is too small. On the contrary, if the amount of the aliphatic aromatic polyester of the present invention is too small, the impact resistance, tear strength, and flexibility are improved by using the aliphatic aromatic polyester of the present invention. Such effects are impaired.

  Therefore, the lower limit of the content of the other polyester in the composition is 5% by weight and the upper limit is 90% by weight, preferably the lower limit is 10% by weight, the upper limit is 80% by weight, and more preferably the lower limit is 20% by weight. Is preferably used so as to be 70% by weight.

  The sheet formed by blending the aliphatic aromatic polyester of the present invention with wood flour, which is an organic filler, has a low tensile elastic modulus and is suitable as a herbicidal sheet for covering uneven ground.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples as long as the gist thereof is not exceeded.

  In addition, the measurement methods and molding methods for various physical properties and the like in the following are as follows.

  Reduced viscosity (ηsp / c): The copolymers obtained in Examples and Comparative Examples were added in phenol / 1,1,2,2-tetrachloroethane (1: 1 weight ratio) at a concentration of 0.5 g / dl. The solution viscosity was determined from the solution viscosity measured at 30 ° C.

  Hot pressing: Using a 38-ton press (ram diameter 150 mmφ, 250 mm square, Kamijima test press), hot pressing was performed at 150 to 230 ° C. to produce a press film having a thickness of 150 to 250 μm.

  Tensile test: A sample was punched out into a dumbbell shape from the press film obtained by the above hot press, a tensile test was performed according to JIS K7127, and a tensile elastic modulus was measured.

¹ H-NMR measurement: The molar fraction of each component of the obtained copolymer was measured by ¹ H-NMR using “AV400” manufactured by Bruker.

Injection molding: The pellets of the resin composition were injection-molded under the conditions of a molding temperature of 190 ° C, a mold temperature of 40 ° C, a screw rotation speed of 80 rpm, and a back pressure of 10 kg / cm ² using a Toshiba Machine IS55EPN molding machine.

  Izod impact test (with notch): Conforms to JIS K7110 (23 ° C)

  Inflation molding: The blended pellets were put into an inflation molding machine having an extruder size of 30φ, and the temperature setting of the extruder and the die was 160 ° C., the blow ratio was 2.5, and the film thickness was 20 μm. The physical properties of the obtained film were measured according to JIS Z1702.

  Calendar molding: The resin composition was put into a PL2000 plastic kneading tester manufactured by Parker Corporation, melted and kneaded at a case temperature of 165 ° C. for 5 minutes, and then rolled by a calendar of 10 inches × 25 inches × 4 rolls manufactured by Minamisenju Seisakusho. A sheet was formed by rolling at 145 ° C.

  Tear test: Conforms to JIS K7128 (Elmendorf tear strength)

  Biodegradability test: A sample for biodegradation test (2.0 cm × 2.5 cm, thickness 150 to 250 μm) was prepared from the press film obtained by the above-mentioned hot press, and a black burdock soil (soil moisture content: 42%) was prepared. A sample for biodegradation test is buried in the test pad that is put in, put in a thermo-hygrostat adjusted to a temperature of 30 ° C and humidity of 50%, the test is started, and the sample for biodegradation test over time The weight loss rate (%) was measured.

Example 1
In a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer and a pressure reducing port, 56 g of succinic acid, 107 g of 1,4-butanediol, 60 g of dimethyl terephthalate, 0.1 g of malic acid, and titanium tetra 2.1 g of a 1,4-butanediol solution in which 5% by weight of butyrate was dissolved in advance and 3.5 g of a 1,4-butanediol solution in which 2% by weight of magnesium acetate tetrahydrate had been dissolved in advance were charged.

Nitrogen gas was introduced into the container while stirring the contents of the container, and the system was placed in a nitrogen atmosphere by vacuum replacement. Next, the temperature was raised to 185 ° C. while stirring the system, and the reaction was carried out at this temperature for 45 minutes to 1 hour. Next, it heated up to 220 degreeC over 1 hour 30 minutes. Thereafter, the temperature was raised to 230 ° C. over 1 hour, and at the same time, the pressure was reduced to 0.07 × 10 ³ Pa or less over 1 hour 30 minutes, and the polymerization was continued while maintaining the heated and reduced pressure state. Then, the polymerization was terminated to obtain a pale yellow copolymer.

  The reduced viscosity (ηsp / c) of the obtained aliphatic aromatic polyester was 2.1. The mol% of each structural unit in the aliphatic aromatic polyester was 29 mol% succinic acid unit, 21 mol% terephthalic acid unit, and 50 mol% 1,4-butanediol unit. Moreover, the malic acid unit was 0.04 mol% with respect to 100 mol% in total of these.

  Moreover, the tensile elastic modulus of the hot-pressed film of this aliphatic aromatic polyester was 45 MPa.

Example 2
An aliphatic aromatic polyester was obtained in the same manner as in Example 1 except that 45 g of succinic acid, 64 g of dimethyl terephthalate, and 0.4 g of malic acid were used. The tensile elastic modulus of this aliphatic aromatic polyester hot-press film was 75 MPa.

Examples 3 and 4
Instead of 0.1 g of malic acid, 17 g of lactic acid 90 wt% aqueous solution and 1.0 g of malic acid (Example 3), or 17 g of 90 wt% lactic acid aqueous solution and 2.1 g of malic acid (implemented) A copolymer was obtained in the same manner as in Example 1 except that Example 4) was used.

Example 5
In a reaction vessel, 1,4-butanol containing 56% succinic acid, 107 g 1,4-butanediol, 56 g dimethyl terephthalate, 8 g dimethyl isophthalate, 2.0 g malic acid, and 4% by weight of titanium tetrabutyrate was dissolved in advance. Example 1 except that 2.7 g of butanediol solution, 3.5 g of 1,4-butanediol solution in which 2% by weight of magnesium acetate tetrahydrate had been dissolved in advance, and 2 g of 90% by weight aqueous solution of lactic acid were charged. Was reacted to obtain a pale yellow copolymer.

Example 6
A reaction was carried out in the same manner as in Example 5 except that a 90% by weight aqueous solution of lactic acid was not added to obtain a pale yellow copolymer.

Comparative Example 1
A copolymer was obtained in the same manner as in Example 3 except that malic acid was not added.

Comparative Example 2
A copolymer was obtained in the same manner as in Example 3 except that 11 g of malic acid was used.

Comparative Example 3
A reaction was carried out in the same manner as in Example 5 except that malic acid was removed from the raw material of Example 5 to obtain a pale yellow copolymer.

The measurement results of the tensile modulus of the copolymers of Examples 1 to 6 and Comparative Examples 1 to 3 are shown in Table 1 together with the time required for polymerization.
In the following, “aliphatic dicarboxylic acid unit ratio (mol%)” means “aliphatic dicarboxylic acid unit ratio (molar ratio) when all dicarboxylic acid units are 1”, and “lactic acid copolymerization amount ( "Mol%)" means "ratio of lactic acid units (mol%) in all polymer constituent units", and "malic acid copolymerization amount (mol%)" means "ratio of malic acid units in all polymer constituent units" (Mol%) ". The same applies to Table 2 and later.

  From Table 1, it can be seen that, in the resin having the same dicarboxylic acid composition, the polymerization time becomes longer when the amount of malic acid which is a crosslinking component is small, and the polymerization time becomes shorter when the amount is larger. When the polymerization time is lengthened, productivity is deteriorated, but when the polymerization time is too early, it becomes difficult to obtain a resin having a stable molecular weight. From this, it can be said that an appropriate amount of the crosslinking component is desirable.

Example 7
As raw materials, 51 g of succinic acid, 98 g of 1,4-butanediol, 56 g of dimethyl terephthalate, 0.4 g of malic acid, 17 g of a 90% by weight aqueous solution of lactic acid, and 1,4-butane in which 5% by weight of titanium tetrabutyrate was dissolved in advance. A copolymer was obtained in the same manner as in Example 1 except that 2 g of a diol solution and 3.4 g of a 1,4-butanediol solution in which 2% by weight of magnesium acetate tetrahydrate had been dissolved in advance were charged.

Example 8
As raw materials, 42 g of succinic acid, 81 g of 1,4-butanediol, 46 g of dimethyl terephthalate, 0.1 g of malic acid, 52 g of a 90% by weight aqueous solution of lactic acid, and 1,4-butane in which 5% by weight of titanium tetrabutyrate was dissolved in advance. A copolymer was obtained in the same manner as in Example 1 except that 2 g of a diol solution and 3.4 g of a 1,4-butanediol solution in which 2% by weight of magnesium acetate tetrahydrate had been dissolved in advance were charged.

Example 9
As raw materials, 32 g of succinic acid, 64 g of 1,4-butanediol, 35 g of dimethyl terephthalate, 0.4 g of malic acid, 92 g of a 90% by weight aqueous solution of lactic acid, and 1,4-butane in which 4% by weight of titanium tetrabutyrate was dissolved in advance. A copolymer was obtained in the same manner as in Example 1 except that 3 g of a diol solution and 3.5 g of a 1,4-butanediol solution in which 2% by weight of magnesium acetate tetrahydrate had been dissolved in advance were charged.

Example 10
As raw materials, 23 g of succinic acid, 44 g of 1,4-butanediol, 25 g of dimethyl terephthalate, 0.6 g of malic acid, 200 g of a 90% by weight aqueous solution of lactic acid, and 1,4-butane in which 4% by weight of titanium tetrabutyrate was dissolved beforehand A copolymer was obtained in the same manner as in Example 1 except that 4 g of a diol solution and 4.6 g of a 1,4-butanediol solution in which 2% by weight of magnesium acetate tetrahydrate had been dissolved in advance were charged.

  The results obtained by measuring the tensile modulus of the copolymers obtained from Examples 7 to 10 are shown in Table 2 together with the results of Example 1.

Comparative Example 4
The tensile elastic modulus of polylactic acid was measured, and the results are shown in Table 2.

  Table 2 shows that a more flexible polymer can be obtained by copolymerizing an appropriate amount of lactic acid units.

Example 11
In a reaction vessel, 33 g of succinic acid, 95 g of 1,4-butanediol, 80 g of dimethyl terephthalate, 0.1 g of malic acid, 16 g of 90% by weight lactic acid aqueous solution, and 4% by weight of titanium tetrabutyrate were dissolved in advance. The reaction was conducted in the same manner as in Example 1 except that 2.5 g of 1,4-butanediol solution and 3.5 g of 1,4-butanediol solution in which 2% by weight of magnesium acetate tetrahydrate had been dissolved in advance were charged. As a result, a pale yellow copolymer was obtained.

Examples 12-14
The total number of moles of succinic acid and dimethyl terephthalate was the same as in Example 11, and the feed ratio of succinic acid and dimethyl terephthalate was changed so that the ratio of aliphatic dicarboxylic acid units (succinic acid) shown in Table 3 was obtained. The reaction was conducted in the same manner as in Example 11 except that malic acid was changed to 0.4 g to obtain a pale yellow copolymer.

Examples 15-18
As raw materials, 35 g of succinic acid, 87 g of dimethyl terephthalate, 100 g of 1,4-butanediol (Example 15), 26 g of succinic acid, 100 g of dimethyl terephthalate, 100 g of 1,4-butanediol (Example 16), or succinic acid 17 g of acid, 111 g of dimethyl terephthalate, 77 g of 1,4-butanediol (Example 17), or 78 g of succinic acid, 32 g of dimethyl terephthalate, 90 g of 1,4-butanediol (Example 18), and 0.4 g of malic acid In addition, 2.8 g of a 1,4-butanediol solution in which 3% by weight of titanium tetrabutyrate was dissolved in advance and 3.6 g of a 1,4-butanediol solution in which 2% by weight of magnesium acetate tetrahydrate had been dissolved in advance were charged. Except that, the reaction was carried out in the same manner as in Example 1 to obtain a pale yellow copolymer.

Example 19
In a reaction vessel, 1,4-butanol containing 57% of succinic acid, 108 g of 1,4-butanediol, 56 g of dimethyl terephthalate, 8 g of dimethyl isophthalate, 0.4 g of malic acid and 4% by weight of titanium tetrabutyrate was dissolved in advance. The reaction was conducted in the same manner as in Example 1 except that 2.7 g of butanediol solution and 3.5 g of 1,4-butanediol solution in which 2% by weight of magnesium acetate tetrahydrate had been dissolved in advance were charged. A yellow copolymer was obtained.

Example 20
A pale yellow copolymer was obtained in the same manner as in Example 19 except that the amount of dimethyl terephthalate charged was 51 g and the amount of dimethyl isophthalate charged was 16 g.

Example 21
A pale yellow copolymer was obtained in the same manner as in Example 19 except that 1.8 g of a 90% by weight aqueous lactic acid solution was further added to the raw material.

Example 22
A pale yellow copolymer was obtained in the same manner as in Example 20, except that 1.6 g of a 90% by weight aqueous lactic acid solution was further added to the raw material.

  Table 3 shows the results obtained by measuring the tensile modulus of the copolymers of Examples 11 to 22.

Comparative Examples 5 and 6
“Novaduran (registered trademark) 5010R5” (manufactured by Mitsubishi Chemical Corporation, Comparative Example 5) as a commercially available polybutylene terephthalate resin, and “GS Pla (registered trademark) AZ91T” (manufactured by Mitsubishi Chemical Corporation) as a commercially available polybutylene succinate resin. Comparative Example 6) was measured for tensile modulus and the results are shown in Table 3.

  From Table 3, it can be seen that a flexible copolymer can be obtained by copolymerizing an aliphatic dicarboxylic acid unit and an aromatic dicarboxylic acid unit. Moreover, it turns out that the result which may copolymerize 2 or more types of dicarboxylic acid is obtained in that case.

Example 23
Table 4 shows pellets of the aliphatic aromatic polyester obtained in Example 2 and polylactic acid (“Lacia (registered trademark) H-400” manufactured by Mitsui Chemicals, Inc., MFR = 3 g / 10 min, melting point: 166 ° C.). With a compound of No. 1, compounded at 190 ° C. using a 30 mmφ small-sized co-rotating twin screw extruder manufactured by Nippon Steel Works, the obtained pellets were injection molded to prepare test pieces. Next, this test piece was allowed to stand in a hot air dryer (manufactured by Tabai, LC-112) and heat-treated at 70 ° C. for 4 hours to promote crystallization. An Izod impact strength test was performed on the test pieces before and after the heat treatment.

Examples 24, 25, 26
As the aliphatic aromatic polyester, the aliphatic aromatic polyester obtained in Example 12 (Example 24) or the aliphatic aromatic polyester obtained in Example 7 (Examples 25 and 26) are shown in Table 4. Except that it was used, an Izod impact test was performed on the test pieces before and after the heat treatment obtained in the same manner as in Example 23.

Comparative Example 7
A test piece before and after heat treatment obtained in the same manner as in Example 24 using polylactic acid (“Lacia (registered trademark) H-400” manufactured by Mitsui Chemicals, Inc.) was subjected to an Izod impact test. Together with the results of -26, the results are shown in Table 4.

  From Table 4, it can be seen that the injection molded article using the aliphatic aromatic polyester of the present invention has high Izod impact strength.

Example 27
Pellets of 30% by weight of the aliphatic aromatic polyester obtained in Example 2 and 70% by weight of polybutylene succinate (“GS Pla (registered trademark) AZ91T” manufactured by Mitsubishi Chemical Corporation), which is an aliphatic polyester, were used. After blending, the film was formed by feeding into an extruder with an extruder size of 30φ. At that time, the temperature setting of the extruder and the die was 160 ° C., the blow ratio was 2.5, and the film thickness was 20 μm. The resulting blown film was evaluated for tensile strength and elongation, Elmendorf tear strength, and the like, and Table 5 shows the results. In Table 5, MD indicates the resin flow direction, and TD indicates a direction perpendicular thereto. Moreover, when measuring the Elmendorf tear strength of MD direction, it evaluated by 8 sheets of film overlap.

Examples 28 and 29
Implementation was carried out except that the aliphatic aromatic polyester obtained in Example 12 (Example 28) or the aliphatic aromatic polyester obtained in Example 7 (Example 29) was used as the aliphatic aromatic polyester. Various evaluations were similarly made on the blown film of the resin composition obtained in the same manner as in Example 27, and the results are shown in Table 5.

Comparative Example 8
Polybutylene succinate (“GS Pla (registered trademark) AZ91T” manufactured by Mitsubishi Chemical Corporation) was subjected to various evaluations in the same manner as in Example 27 for the film obtained by inflation molding in the same manner as in Example 27. The results are shown in Table 5.

  From Table 5, it can be seen that an inflation molded film using the aliphatic aromatic polyester of the present invention has high tear strength.

Example 30
The aliphatic aromatic polyester synthesized in Example 21 was mixed with 1% by weight of a carbodiimide compound (Nisshinbo Co., Ltd., product name: Carbodilite LA-1 (carbodiimide equivalent 247)), and Toyo Seiki's Laboplast Mill 10C100 was used. Kneading was performed to obtain a resin composition in which the carboxylic acid terminal of the polyester was sealed, and the kneading conditions were 190 ° C., 100 rpm, and 5 minutes.
This resin composition is held at 50 ° C. and 90% RH for 8 weeks, the reduced viscosity before and after the holding is measured, and the ratio (%) of the reduced viscosity after holding to the reduced viscosity before holding is calculated. The viscosity retention was determined.

Example 31
A resin composition was obtained in the same manner as in Example 30 except that the carbodiimide compound was blended in an amount of 3% by weight based on the aliphatic aromatic polyester. Similarly, the viscosity was maintained at 50 ° C. and 90% RH for 8 weeks Retention was determined.

Reference example 1
The viscosity retention when the aliphatic aromatic polyester of Example 21 was held for 8 weeks under the conditions of 50 ° C. and 90% RH without blending the carbodiimide compound was determined.
The results of Examples 30 and 31 and Reference Example 1 are summarized in Table 6.

  From Table 6, it can be seen that hydrolysis resistance is improved by end-capping with a carbodiimide compound.

Examples 32-34
Aliphatic aromatic polyester obtained in Example 1 (Example 32), Aliphatic aromatic polyester obtained in Example 7 (Example 33), Aliphatic aromatic polyester obtained in Example 21 (Implementation) Each hot press film of Example 34) was prepared and subjected to a biodegradability test by embedding in the soil by the method described above. The results are shown in Table 7.

  As shown in Table 7, it was confirmed that the aliphatic aromatic polyester of the present invention was biodegraded in the soil.

Example 35
The aliphatic aromatic polyester obtained in Example 21 was blended with 1% by weight of zinc stearate as a lubricant, 3% by weight of stearic acid as a release agent, and 35% by weight of wood flour having an average particle diameter of about 0.3 mm. Then, a herbicidal sheet having a thickness of 1 mm, a width of 300 mm and a length of 1000 mm was formed by calendering using the obtained composition, and the tensile elastic modulus of the sheet was evaluated.

Comparative Example 9
A sheet obtained by calendering in the same manner as in Example 35 except that a commercially available aliphatic aromatic polyester ("Ecoflex" manufactured by BASF) was used instead of the aliphatic aromatic polyester obtained in Example 21. The evaluation was conducted in the same manner as in Example 35.
These results are shown in Table 8.

  From Table 8, it can be seen that the calendered sheet using the aliphatic aromatic polyester of the present invention has a low tensile elastic modulus and is suitable as a weedproof sheet for covering uneven ground.

Claims (10)

  An aliphatic aromatic polyester containing at least an aliphatic dicarboxylic acid unit, an aromatic dicarboxylic acid unit, and an aliphatic and / or alicyclic diol unit, and further a structural unit having an ester-forming group having three or more functional groups. And the content of the structural unit having a trifunctional or higher functional ester-forming group in the aliphatic aromatic polyester is 0.0001 to 4 mol% with respect to the total of all the structural units of the aliphatic aromatic polyester. A featured aliphatic aromatic polyester.   The aliphatic ratio according to claim 1, wherein the molar ratio of the aliphatic dicarboxylic acid unit to the aromatic dicarboxylic acid unit is aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit = 10/90 to 90/10. Aromatic polyester.   The aliphatic aromatic polyester according to claim 1 or 2, wherein the aliphatic dicarboxylic acid unit contains at least succinic acid and the terephthalic acid and / or isophthalic acid unit as the aromatic dicarboxylic acid unit.   Furthermore, it contains a hydroxycarboxylic acid unit, and the content ratio of the hydroxycarboxylic acid unit in the aliphatic aromatic polyester is 0.01 to 50 mol% with respect to the total of all the structural units of the aliphatic aromatic polyester, The aliphatic aromatic polyester according to any one of claims 1 to 3.   The aliphatic aromatic polyester according to any one of claims 1 to 4, having a tensile modulus of 300 MPa or less.   A polyester comprising an aliphatic and / or alicyclic diol unit and an aliphatic and / or alicyclic dicarboxylic acid unit as constituent units (excluding an aromatic dicarboxylic acid unit), and any one of claims 1 to 5 A resin composition comprising the aliphatic aromatic polyester according to claim 1.   A resin composition comprising a polylactic acid aliphatic polyester and the aliphatic aromatic polyester according to any one of claims 1 to 5.   A film formed by molding a resin composition containing at least the aliphatic aromatic polyester according to any one of claims 1 to 5.   A sheet formed by molding a resin composition containing at least the aliphatic aromatic polyester according to any one of claims 1 to 5.   A herbicidal sheet formed by molding a resin composition containing at least the aliphatic aromatic polyester according to any one of claims 1 to 5.