JP5167502B2 - Aliphatic aromatic polyester and resin composition thereof - Google Patents

Description

  The present invention relates to an aliphatic aromatic polyester, a resin composition containing the aliphatic aromatic polyester, and the resin composition. 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 included a hydroxycarboxylic acid unit in a predetermined ratio in an aliphatic aromatic polyester, while maintaining biodegradable characteristics. Improve impact resistance, flexibility, thermal decomposition resistance, productivity, tear resistance, and change the content of hydroxycarboxylic acid units to increase the biodegradation rate of aliphatic aromatic polyester Has been found to be controllable, 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, an aliphatic and / or alicyclic diol unit, and a hydroxycarboxylic acid unit. And 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, and hydroxy in the aliphatic aromatic polyester The content ratio of the carboxylic acid unit is 0.01 to 50 mol% with respect to the total of all the structural units of the aliphatic aromatic polyester, and contains at least a succinic acid unit as the aliphatic dicarboxylic acid unit, and the aromatic dicarboxylic acid unit. Containing a terephthalic acid and / or isophthalic acid unit as well as a structural unit having a trifunctional or higher functional ester-forming group, The content ratio of the structural unit having a tri- or higher functional ester-forming group in the aromatic aromatic polyester is 0.0001 to 4 mol% with respect to the total of all the structural units of the aliphatic aromatic polyester. It resides in an aliphatic aromatic polyester.

The second gist of the present invention resides in the aliphatic aromatic polyester according to claim 1, which has a tensile elastic modulus of 300 MPa or less.

The third gist of the present invention is 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 an aliphatic aromatic polyester according to claim 1 or 2 .

The fourth gist of the present invention resides in a resin composition containing a polylactic acid-based aliphatic polyester and the aliphatic aromatic polyester according to claim 1 or 2 .

The fifth gist of the present invention resides in a film formed by molding a resin composition containing at least the aliphatic aromatic polyester according to claim 1 or 2 .

The sixth gist of the present invention resides in a sheet formed by molding a resin composition containing at least the aliphatic aromatic polyester according to claim 1 or 2 .

The seventh gist of the present invention resides in a herbicidal sheet formed by molding a resin composition containing at least the aliphatic aromatic polyester according to claim 1 or 2 .

  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 comprises an aliphatic dicarboxylic acid unit, an aromatic dicarboxylic acid unit, an aliphatic and / or alicyclic diol unit, and a hydroxycarboxylic acid unit, and the hydroxycarboxylic acid unit in the aliphatic aromatic polyester. The content ratio is 0.01 to 50 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 a hydroxycarboxylic acid component is further included.
In the present invention, the component refers to a raw material that becomes a 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 such that the lower limit is 10 mol% as the ratio of the aliphatic dicarboxylic acid unit to the total of these units. 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.

  When the proportion of the aliphatic dicarboxylic acid unit is less than the above lower limit and the amount of the aromatic dicarboxylic acid unit 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. Furthermore, the biodegradation rate increases as the content ratio of the hydroxycarboxylic acid unit increases.

(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. Of these, succinic acid, glutaric acid, sebacic acid, dimer acid and dodecanedioic acid, and their lower alkyl (eg, alkyl having 1 to 4 carbon atoms) ester derivatives are preferred, and succinic acid and succinic acid are particularly preferred. 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) Hydroxycarboxylic acid unit Hydroxycarboxylic acid and hydroxycarboxylic acid derivative (hereinafter sometimes referred to as “hydroxycarboxylic acid component”) constituting the hydroxycarboxylic acid unit include one hydroxyl group and carboxyl group in the molecule. If it is a compound or its derivative which has, it will not specifically limit. 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 content ratio of the hydroxycarboxylic acid unit is preferably 0.01 mol%, more preferably 0.05 mol%, based on the total of all the structural units constituting the aliphatic aromatic polyester of the present invention. is there. The upper limit is 50 mol%, preferably 30 mol%, and most preferably 20 mol%. If the content of the hydroxycarboxylic acid unit in the aliphatic aromatic polyester is higher than the above upper limit, the mechanical properties are lowered, and the production causes a problem that the volatile matter is increased, and if it is less than the lower limit, the tensile elongation is reduced. Tend to.

  In the aliphatic aromatic polyester of the present invention, the content ratio of the hydroxycarboxylic acid unit is the above upper limit (50 mol%) and lower limit (0. 0%) relative to the total of all the structural units constituting the aliphatic aromatic polyester of the present invention. (01%), the higher the content ratio of the hydroxycarboxylic acid unit, the faster the biodegradation rate. That is, the aliphatic aromatic polyester of the present invention changes the content of the hydroxycarboxylic acid unit within the above upper limit (50 mol%) and lower limit (0.01%), thereby making the aliphatic aromatic polyester of the present invention. It has the characteristic that the biodegradation rate of polyester can be controlled.

(5) Structural unit having trifunctional or higher ester-forming group A unit containing a trifunctional or higher functional ester-forming group may be introduced into the aliphatic aromatic polyester of the present invention. The compound constituting the structural unit having a trifunctional or higher functional ester-forming group includes a trifunctional or higher polyhydric alcohol; a trifunctional or higher polyvalent carboxylic acid or its anhydride, an acid chloride, an ester; And at least one trifunctional or higher polyfunctional compound selected from the group consisting of hydroxycarboxylic acids or anhydrides, acid chlorides and esters thereof.

  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.

(6) Other structural units 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. These hydrophilic groups 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. It is also preferable to obtain a polyester carbonate by adding 20 mol% or less, preferably 10 mol% or less with respect to the amount.

  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.

  Further, 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, and the aliphatic aromatic polyester is sealed by sealing the polyester terminal group. The improvement of hydrolysis resistance can be expected.

  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 include diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, di-β-naphthylcarbodiimide, N, N′-di-2,6-diisopropylphenylcarbodiimide. These may be used individually by 1 type, and may mix and use 2 or more types.

(7) 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 an excess of 1 to 100 mol%, preferably 5 to 80 mol%, more preferably 10 to 60 mol%.

  When the hydroxycarboxylic acid component is added, it is preferable to add 1 to 5 moles of the target hydroxycarboxylic acid introduction amount at the time of polycondensation. That is, since some hydroxycarboxylic acids are not introduced into the polyester due to side reactions, sublimation, etc., when the total number of moles of all the monomers constituting the polyester is 100 mol%, 0.01 to 300 mol is used for this. It is preferable to carry out the polycondensation reaction by adding at a ratio of%. If this addition ratio is less than 0.01 mol%, the effect of addition does not appear, and if it is too much, heat resistance, mechanical properties, etc. are insufficient. The lower limit of the more preferable addition ratio is 0.01 mol%, the more preferable lower limit is 0.05 mol%, and the preferable upper limit is 150 mol%, more preferably 100 mol%, most preferably 60 mol%. .

When the hydroxycarboxylic acid component is used, 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.

  In addition, when using a polyfunctional compound having three or more functional groups, the addition time thereof may be any of 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 from the point of simplification of the process to charge simultaneously with other monomers.

  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. 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 the 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 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. In the range, a small amount of other units, 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 An example of an aliphatic polyester that can be used by mixing with the aliphatic aromatic polyester of the present invention is a polylactic acid-based polyester. Specific examples of units constituting the 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. As the 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. Usually, the polylactic acid-based aliphatic polyester 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 comprising 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.

  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, wollastonite. , 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 60% by weight, most preferably the lower limit is 30% by weight and the upper limit is 50% 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 vacuum port, 51 g of succinic acid, 98 g of 1,4-butanediol, 56 g of dimethyl terephthalate, 0.4 g of malic acid, 90 weight of lactic acid 17 g of a 1% aqueous solution, 2 g of a 1,4-butanediol solution in which 5% by weight of titanium tetrabutyrate is dissolved in advance, and 3.3 g of a 1,4-butanediol solution in which 2% by weight of magnesium acetate tetrahydrate is dissolved in advance. Was 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 copolymer was 1.9.

Example 2
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.

Comparative Example 1
As raw materials, 56 g of succinic acid, 107 g of 1,4-butanediol, 60 g of dimethyl terephthalate, 0.1 g of malic acid, and 2.1 g of a 1,4-butanediol solution in which 5% by weight of titanium tetrabutyrate was dissolved in advance, acetic acid A copolymer was obtained in the same manner as in Example 1 except that 3.5 g of a 1,4-butanediol solution in which 2% by weight of magnesium tetrahydrate had been dissolved in advance was charged.

Example 3
In a reaction vessel, 57 g of succinic acid, 110 g of 1,4-butanediol, 56 g of dimethyl terephthalate, 8 g of dimethyl isophthalate, 0.3 g of malic acid, 1.8 g of 90% by weight lactic acid aqueous solution, and titanium tetrabutyrate are prepared in advance. Example, except that 2.9 g of 1,4-butanediol solution dissolved in 4% by weight 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. The reaction was carried out in the same manner as in 1 to obtain a pale yellow copolymer.

Example 4
A light yellow copolymer was obtained in the same manner as in Example 3 except that 51 g of dimethyl terephthalate and 16 g of dimethyl isophthalate were used.

Comparative Examples 2 and 3
A pale yellow copolymer was obtained in the same manner as in Example 3 (Comparative Example 2) or Example 4 (Comparative Example 3) except that the 90% by weight lactic acid aqueous solution was removed from the raw material.

The measurement results of the tensile modulus of the copolymers obtained in Examples 1 to 4 and Comparative Examples 1 to 3 are summarized in Table 1 together with the time required for polymerization.
In Table 1, “hydroxycarboxylic acid content (mol%)” means “content ratio (mol%) of hydroxycarboxylic acid units to the total of all constituent units of aliphatic aromatic polyester”. The same applies to Table 2 and later.

  From Table 1, it can be seen that, when compared with the same dicarboxylic acid composition, the addition of lactic acid, which is a hydroxycarboxylic acid, can accelerate the polymerization and increase the productivity. Moreover, it turns out that a more flexible resin can be obtained by adding hydroxycarboxylic acid.

Example 5
In the reaction vessel, 33 g of succinic acid, 95 g of 1,4-butanediol, 80 g of dimethyl terephthalate, 16 g of 90% by weight lactic acid aqueous solution, 0.3 g of malic acid 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 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. A pale yellow copolymer was obtained.

Examples 6-8
The total number of moles of succinic acid and dimethyl terephthalate is the same as in Example 5, so that the molar ratio of aliphatic dicarboxylic acid (succinic acid) units / aromatic dicarboxylic acid (terephthalic acid) units listed in Table 2 is obtained. A copolymer was obtained in the same manner as in Example 5 except that the charging ratio of acid and dimethyl terephthalate was changed.

Example 9
A pale yellow copolymer was obtained in the same manner as in Example 7 except that malic acid was not added to the raw material.

Examples 10-12
A pale yellow copolymer was obtained in the same manner as in Example 7 except that 1.0 g (Example 10), 2.1 g (Example 11), or 11 g (Example 12) of malic acid was used. .

Example 13
In a reaction vessel, 1,4-butanol containing 56% succinic acid, 107 g 1,4-butanediol, 53 g dimethyl terephthalate, 8 g dimethyl isophthalate, 2.0 g malic acid and 4% by weight titanium tetrabutyrate previously dissolved. 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 14
Except that malic acid was removed from the raw material of Example 13, the reaction was carried out in the same manner as in Example 13 to obtain a pale yellow copolymer.

Table 2 summarizes the measurement results of the tensile modulus of the copolymers of Examples 5 to 14 and Comparative Examples 4 and 5.
In the following, “crosslinking component content (mol%)” means “content ratio (moles of malic acid units) in the aliphatic aromatic polyester having a trifunctional or higher functional ester-forming group”. %) ”.

  From Table 2, it can be seen that a suitable range exists for the aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit (molar ratio). Moreover, it turns out that the result which may copolymerize various dicarboxylic acids is obtained in that case. Furthermore, it can be seen that good results can be obtained even if a crosslinking component is added.

Examples 15 and 16
A hot press film of the copolymer obtained in Example 1 (Example 15) and the copolymer obtained in Example 2 (Example 16) was prepared, and in the soil according to the biodegradability test method described above. Was evaluated for biodegradability.

Comparative Example 6
Polymerization was carried out in the same manner as in Example 1 except that the 90% by weight lactic acid aqueous solution was removed from the raw material to obtain a pale yellow copolymer. A hot press film of the copolymer was prepared, and biodegradability was evaluated in the same manner as in Example 15.

Comparative Example 7
A polylactic acid hot press film was prepared, and biodegradability was evaluated in the same manner as in Example 15.

  The results of Examples 15 and 16 and Comparative Examples 6 and 7 are summarized in Table 3.

  From Table 3, the content ratio of the hydroxycarboxylic acid unit is within the upper limit (50 mol%) and lower limit (0.01%) with respect to the total of all the structural units constituting the aliphatic aromatic polyester of the present invention. It can be seen that increasing the content ratio of the hydroxycarboxylic acid unit increases the biodegradation rate, and conversely decreasing the content ratio decreases the biodegradation rate.

  That is, in the aliphatic aromatic polyester of the present invention, the content of hydroxycarboxylic acid units is the upper limit (50 mol%) and the lower limit (0.01%) with respect to the total of all the structural units constituting the aliphatic aromatic polyester. ), The biodegradability rate can be controlled by changing the content ratio of the hydroxycarboxylic acid unit.

Example 17
Table 4 shows pellets of the aliphatic aromatic polyester obtained in Example 6 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. The Izod impact strength test was performed on the test pieces before and after the heat treatment, and the results are shown in Table 4.

Example 18
Except that the copolymer obtained in Example 1 was used in the proportion shown in Table 4 as the aliphatic aromatic polyester, an Izod impact test was performed on the test piece before and after the heat treatment obtained in the same manner as in Example 17. The results are shown in Table 4.

Comparative Example 8
Using polylactic acid (“Lacia (registered trademark) H-400” manufactured by Mitsui Chemicals, Inc.), an Izod impact test was performed on the test pieces before and after the heat treatment obtained in the same manner as in Example 17, and the results are shown. This is shown in FIG.

  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 19
Pellets of 30% by weight of the aliphatic aromatic polyester obtained in Example 6 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 inflation molding machine having 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.

Example 20
Except that the copolymer obtained in Example 1 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 19. Are shown in Table 5.

Comparative Example 9
Polybutylene succinate ("GS Pla (registered trademark) AZ91T" manufactured by Mitsubishi Chemical Corporation) was subjected to various evaluations in the same manner as in Example 19 for the film obtained by inflation molding in the same manner as in Example 19. The results are shown in Table 5.

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

Example 21
Carbodiimide compound (manufactured by Nisshinbo Co., Ltd., product name: Carbodilite LA-1 (carbodiimide equivalent 247)) is blended in an amount of 1% by weight with the aliphatic aromatic polyester synthesized in Example 3, using a lab plast mill 10C100 manufactured by Toyo Seiki. 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 22
Except for blending 3% by weight of the carbodiimide compound with respect to the aliphatic aromatic polyester, a resin composition was obtained in the same manner as in Example 21. Similarly, the viscosity was maintained for 8 weeks at 50 ° C. and 90% RH. Retention was determined.

Reference example 1
The viscosity retention when the aliphatic aromatic polyester of Example 3 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 21 and 22 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.

Example 23
The copolymer obtained in Example 3 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. Using the obtained composition, a herbicidal sheet having a thickness of 1 mm, a width of 300 mm and a length of 1000 mm was formed by calendar molding, and the tensile elastic modulus of the sheet was evaluated.

Comparative Example 10
About the sheet obtained by calender molding in the same manner as in Example 23 except that a commercially available aliphatic aromatic polyester (“Ecoflex” manufactured by BASF) was used instead of the copolymer obtained in Example 3, Evaluation was performed in the same manner as in Example 23.

  The results of Example 23 and Comparative Example 10 are shown in Table 7.

  It can be seen from Table 7 that the calendered sheet using the aliphatic aromatic polyester of the present invention has a low tensile elastic modulus and is suitable for a weedproof sheet for covering uneven ground.

Claims (7)

An aliphatic aromatic polyester comprising at least an aliphatic dicarboxylic acid unit, an aromatic dicarboxylic acid unit, an aliphatic and / or alicyclic diol unit, and a hydroxycarboxylic acid unit,
The molar ratio of the aliphatic dicarboxylic acid unit and the aromatic dicarboxylic acid unit is aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit = 10/90 to 90/10,
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,
Containing at least succinic acid units as aliphatic dicarboxylic acid units, containing terephthalic acid and / or isophthalic acid units as aromatic dicarboxylic acid units,
Further, the content ratio of the structural unit having a trifunctional or higher functional ester-forming group in the aliphatic aromatic polyester is a total of all the structural units of the aliphatic aromatic polyester. An aliphatic aromatic polyester characterized in that the content is 0.0001 to 4 mol% based on the weight. The aliphatic aromatic polyester according to claim 1, which has a tensile modulus of 300 MPa or less. The polyester containing an aliphatic and / or alicyclic diol unit and an aliphatic and / or alicyclic dicarboxylic acid unit as a constituent unit (however, excluding an aromatic dicarboxylic acid unit), and the polyester according to claim 1 or 2 . A resin composition comprising: an aliphatic aromatic polyester. The resin composition containing polylactic acid-type aliphatic polyester and the aliphatic aromatic polyester of Claim 1 or 2 . Molding comprising film according to claim 1 or a resin composition containing at least an aliphatic aromatic polyester according to 2. Claim 1 or sheet obtained by molding at least containing a resin composition of an aliphatic aromatic polyester according to 2. Claim 1 or weed sheet obtained by molding at least containing a resin composition of an aliphatic aromatic polyester according to 2.