JP2007131797A - Resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a resin composition that has excellent heat resistance and impact resistance and comprises a lactic acid-based polymer as a main component and a molding obtained from the same. <P>SOLUTION: The resin composition comprises 100 parts wt. of the total of 1-99 parts wt. of a lactic acid-based polymer having 0%-40% degree of crystallization and 99-1 part wt. of a polycarbonate resin and 1-20 parts wt. of an impact improver. The molding is obtained from the same. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a resin composition comprising a plant-derived resin and excellent in heat resistance and impact resistance.

  In general, polymer materials represented by polyolefin, polystyrene, polyester, polyamide, polyacrylate, polycarbonate, polyimide, and the like are effectively used as various industrial materials. These general-purpose polymer materials are excellent in mechanical properties such as heat resistance and impact resistance, but if they are disposed of incorrectly, they will increase the amount of dust and hardly decompose in the natural environment. When buried, it remains in the ground semipermanently.

  On the other hand, polylactic acid or a copolymer of lactic acid and other hydroxycarboxylic acid has been developed as a biodegradable polymer of a thermoplastic resin. These polymers are 100% biodegradable within a few months to a year within the animal's body, and when placed in soil or seawater, they begin to degrade in a few weeks in a moist environment, approximately one to several years. In addition, the decomposition product has characteristics that it becomes lactic acid, carbon dioxide and water which are harmless to the human body.

In recent years, the development of OA / home appliance casings, automobile parts, bottles, films, sheets, tableware and the like using polylactic acid has been promoted. In general, these applications often require high impact resistance, and it is difficult to use polylactic acid having very low impact resistance. As a means for using polylactic acid for these applications, Patent Document 1 discloses a resin composition comprising an aromatic polycarbonate, polylactic acid, and an impact modifier, but because the polylactic acid used has high crystallinity, When the molded product is placed in a high temperature atmosphere, there is a problem that dimensional change or deformation occurs. Patent Document 2 discloses a resin composition comprising polylactic acid, a flame retardant, and a resin other than polylactic acid, but similarly uses polylactic acid having high crystallinity.
JP-A-2005-48067 JP 2004-190026 JP

  The problem to be solved by the present invention is to obtain a resin composition having a lactic acid polymer as a main component and excellent in heat resistance and impact resistance, and a molded product thereof.

The present invention comprises 1 to 20 parts by weight of an impact modifier for a total of 100 parts by weight of 1 to 99 parts by weight of a lactic acid polymer having a crystallinity of 0% to 40% and 99 to 1 parts by weight of a polycarbonate resin. A resin composition is provided.
A preferred embodiment of the present invention is the resin composition containing 0.1 to 5 parts by weight of a carbodiimide compound and / or 0.1 to 5 parts by weight of an organic peroxide with respect to 100 parts by weight of a total of a lactic acid-based polymer and a polycarbonate resin. It is.

The resin composition in which the impact modifier includes an aromatic vinyl / conjugated diene block copolymer modified with a polar functional group is also a preferred embodiment of the present invention.
The aromatic vinyl / conjugated diene block copolymer modified with a polar functional group and an aromatic vinyl / conjugated diene block copolymer modified with a basic functional group is also a preferred embodiment of the present invention.

  SBS (styrene / butadiene / styrene copolymer) modified with imino group, SBBS (styrene / butadiene / butylene) modified with imino group, aromatic vinyl / conjugated diene block copolymer modified with polar functional group The styrene copolymer) and the resin composition which is at least one selected from SEBS (styrene / ethylene / butylene / styrene copolymer) modified with an imino group are also a preferred embodiment of the present invention.

  Furthermore, this invention provides the molded object which consists of the said resin composition.

  According to the present invention, a resin composition having a lactic acid polymer as a main component and excellent in heat resistance and impact resistance and a molded product thereof can be obtained.

The present invention will be described in detail below.
[Lactic acid polymer]
The lactic acid-based polymer in the present invention refers to polylactic acid containing only lactic acid as a constituent, polylactic acid copolymer containing lactic acid and a monomer component other than lactic acid, and a mixture thereof.
As the lactic acid used as a raw material for the lactic acid-based polymer, one appropriately selected from L-lactic acid, D-lactic acid, DL-lactic acid or a mixture thereof, or lactic acid such as lactide which is a cyclic dimer of lactic acid is used. be able to. Further, as hydroxycarboxylic acids that can be used in combination with lactic acid, hydroxycarboxylic acids other than lactic acid having 2 to 10 carbon atoms are preferable. Specifically, glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, 5 -Hydroxyvaleric acid, 6-hydroxycaproic acid and the like can be preferably used. Further, cyclic ester intermediates of hydroxycarboxylic acid, for example, glycolide which is a dimer of glycolic acid and cyclic ester of 6-hydroxycaproic acid Ε-caprolactone can also be used.

  As aliphatic dicarboxylic acids, saturated and / or unsaturated aliphatic dicarboxylic acids having 2 to 30 carbon atoms are preferable. Specific examples of saturated aliphatic dicarboxylic acids include oxalic acid, succinic acid, glutaric acid, adipic acid, and pimelic acid. , Suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, phenylsuccinic acid, 1,4-phenylenediacetic acid and the like. Specific examples of the unsaturated aliphatic dicarboxylic acid include fumaric acid, Mention may be made of maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride and the like. These can be used alone or in combination of two or more.

  As the aliphatic diols, aliphatic diols having 2 to 30 carbon atoms are preferable. Specifically, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol, Examples include 1,4-benzenedimethanol. These can be used alone or in combination of two or more.

  Hydroxycarboxylic acids other than lactic acid, aliphatic dicarboxylic acids, and aliphatic diols as raw materials can be used in various combinations so that the lactic acid content in the resulting copolymer and mixture is 50% or more. In the present invention, polylactic acid is particularly preferable as the lactic acid-based polymer.

  Lactic acid-based polymers can be obtained by direct dehydration polycondensation of the above raw materials, or ring-opening polymerization of the above cyclic dimers of milk and hydroxycarboxylic acids, such as lactide and glycolide, or cyclic ester intermediates such as ε-caprolactone. It is obtained by the method.

  In the case of producing by direct dehydration polycondensation, the raw materials lactic acids or lactic acids and hydroxycarboxylic acids, aliphatic dicarboxylic acids and aliphatic diols are preferably used in the presence of an organic solvent, particularly a phenyl ether solvent. Polymerization is performed by a method in which azeotropic dehydration condensation is carried out, and polymerization is performed by a method in which water is removed from a solvent distilled off by azeotropy, and the solvent is made substantially anhydrous, and returned to the reaction system. A molecular weight lactic acid polymer is obtained. The weight average molecular weight of the lactic acid-based polymer is preferably a high molecular weight within a range in which moldability is possible, preferably from 100,000 to 500,000, and more preferably from 150,000 to 400,000. A lactic acid polymer having a weight average molecular weight of 180,000 or more and 300,000 or less is particularly preferably used in order to enhance compatibility with the polycarbonate described later. The relative viscosity of the lactic acid polymer is preferably 2.0 or more and 4.5 or less, preferably 3.0 or more and 4.3 or less, and most preferably 3.3 or more and 4.2 or less.

  As the lactic acid-based polymer used in the present invention, a polymer having low crystallinity or an amorphous polymer is preferably used. The crystallinity of the lactic acid polymer is preferably 40% or less, more preferably 30% or less, and most preferably 20% or less.

When the lactic acid polymer is polylactic acid, its optical purity is preferably 0% to 97%, more preferably 0 to 95%, and most preferably 0 to 90% in order to make it low crystalline or amorphous.
The relative viscosity in the present invention is the time when a chloroform solution in which a sample is dissolved is placed in a Ubbelohde viscometer, left in a constant temperature bath maintained at 30 ° C. and brought to the test temperature, and then a constant volume of the sample flows down in the capillary. Can be determined by the ratio of the time and the flow time of chloroform.
Relative viscosity RV = t ₁ / t ₀ (1)
t ₁ : Sample solution flow time (s)
t ₀ : Flowing time of blank (chloroform) (s)

The crystallinity of the lactic acid polymer in the present invention is the heat of fusion that appears when differential scanning calorimetry (DSC) of a lactic acid polymer heated at 100 ° C. for 4 hours is calculated as the theory of the lactic acid polymer. The value divided by the heat of crystal fusion. When the lactic acid polymer is polylactic acid, the heat of fusion that appears when differential scanning calorimetry (DSC) of polylactic acid heated at 100 ° C. for 4 hours is divided by 93 J / g, the theoretical heat of crystal fusion of polylactic acid. It is a thing. That is, when the lactic acid-based polymer is polylactic acid, the degree of crystallinity = (heat of fusion / 93) × 100. In the present invention, the DSC measurement condition is 10 ° C./min.
Crystallinity = (Heat of fusion / 93) × 100

The optical purity in the present invention is represented by the following formula.
(Optical purity) = 100 × (| [L] − [D] |) / ([L] + [D])
Here, [L] represents the molar concentration of L-lactic acid in the lactic acid unit contained as a structural unit in the lactic acid-based polymer, and [D] represents the molar concentration of D-lactic acid in the polylactic acid.

[Polycarbonate resin]
The polycarbonate resin in the present invention is a resin having a carbonate bond, and those having an aromatic ring are preferably used. Examples of the production method include a method in which a dihydric phenol and a carbonate precursor are reacted by a known method such as a solution method or a melting method. Typical examples of the dihydric phenol include hydroquinone, resorcinol, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane, and 2,2-bis (4-hydroxy-3,5- Dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) sulfide, Bis (4-hydroxyphenyl) sulfone and the like can be mentioned. In particular, a bis (4-hydroxyphenyl) alkane system is suitably used, and 2,2-bis (4-hydroxyphenyl) propane, usually referred to as bisphenol A, is generally used. Examples of the carbonate precursor include carbonyl halides, carbonyl esters, and haloformates. Specific examples include phosgene, diphenyl carbonate, dihaloformates of dihydric phenols, and the like. In the production of the polycarbonate resin, an appropriate molecular weight regulator, branching agent, other modifiers, etc. may be added. The dihydric phenol and the carbonate precursor can be used alone or in combination of two or more, and two or more of the obtained polycarbonate resins may be used in combination.

  The amount of the polycarbonate resin added is preferably 1 to 99 parts by weight, more preferably 20 to 99 parts by weight, and most preferably 30 to 99 parts by weight with respect to 100 parts by weight of the lactic acid-based polymer.

[Impact modifier]
The impact improving material used in the present invention is an elastic polymer used for improving impact resistance, and a known material can be used as a general thermoplastic resin. Specific examples include thermoplastic elastomers such as styrene, polyolefin, polyvinyl chloride, polyurethane, polyester, polyamide, polybutadiene, polyisoprene, and fluororubber, diene, olefin, and acrylic. , Ethylene acrylic, silicone, fluorine compound, urethane, polyether, etc., modified with polar functional groups, polybutylene succinate, polycaprolactone, polybutylene terephthalate adipate, etc. Examples include degradable resins.

  Of these, an aromatic vinyl / conjugated diene block copolymer modified with a polar functional group or a core-shell type graft copolymer is particularly preferably used.

  The aromatic vinyl-conjugated diene block copolymer modified with a polar functional group used in the present invention is composed of a block copolymer derived from aromatic vinyl and a block copolymer derived from conjugated diene. A conjugated diene block copolymer is modified with a polar functional group. As the polar functional group, a carboxyl group, an amino group, an imino group and the like are preferable. From the viewpoint of compatibility with a lactic acid-based polymer or a polycarbonate resin, an aromatic vinyl / conjugated diene block copolymer modified with a basic functional group is preferably used. As the basic functional group, an amino group or an imino group is preferable, and an imino group is more preferable. Specifically, SBS (styrene / butadiene / styrene copolymer) modified with imino group, SBBS (styrene / butadiene / butylene / styrene copolymer) modified with imino group, SEBS modified with imino group (Styrene / ethylene / butylene / styrene copolymer) is preferably used. A hydrogenated block copolymer obtained by adding hydrogen to these remaining aliphatic double bonds is also preferably used. These can be used alone or in combination of two or more. An aromatic vinyl / conjugated diene block copolymer modified with a polar functional group used in the present invention and a method for producing the same are described in, for example, JP-A-2003-313255.

  The core-shell type graft copolymer used in the present invention may be a known one, but the elastic polymer preferably contains 40% or more of a rubber component, and contains 60% or more. Is more preferable. Rubber components in the core-shell type graft copolymer include butadiene rubber, butadiene-acrylic composite rubber, acrylic rubber, acrylic-silicone composite rubber, isobutylene-silicone composite rubber, isoprene rubber, styrene-butadiene rubber, ethylene- Examples thereof include propylene rubber, nitrile rubber, ethylene-acrylic rubber, silicone rubber, and those obtained by adding hydrogen to the unsaturated bond portion.

  Examples of the vinyl compound copolymerized with the rubber component include aromatic vinyl, acrylic acid ester, and methacrylic acid ester. Specifically, styrene, α-methylstyrene, p-methylstyrene, alkoxystyrene, halogenated styrene, methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, octyl acrylate, methyl methacrylate, methacrylic acid Examples include ethyl, butyl methacrylate, cyclohexyl methacrylate, octyl methacrylate and the like. Of these, those containing methacrylic acid esters are particularly preferred.

  The core-shell type graft copolymer has already been commercialized and can be easily obtained. For example, Kane Ace B series (B-56 etc.) of Kaneka Chemical Co., Ltd., Metabrene C series (C-223A etc.), S series (S-2001, SRK200 etc.) W series (W-) of Mitsubishi Rayon Co., Ltd. 450A etc.), Kureha Chemical Co., Ltd. Paraloid EXL series (EXL-2602 etc.), HIA series (HIA-15 etc.), BTA series (BTA-III etc.), KCA series, Rohm and Haas Paraloid Examples include the EXL series and the KM series (KM-336P, KM-357P, etc.).

  The addition amount of the impact modifier is preferably 1 to 20 parts by weight, more preferably 3 to 20 parts by weight, and most preferably 5 to 20 parts by weight with respect to 100 parts by weight of the lactic acid-based polymer.

[Carbodiimide compound]
The carbodiimide compound in the present invention is a compound having at least one carbodiimide group represented by (—N═C═N—) in the molecule, and the carbodiimide compound is a monocarbodiimide compound having one carbodiimide group. Any of the polycarbodiimide compounds having a plurality of carbodiimide groups in a single molecule can be suitably used. Specific examples of the monocarbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, di-β-naphthylcarbodiimide and the like. Of these, dicyclohexylcarbodiimide or diisopropylcarbodiimide is preferable from the viewpoint of industrial availability.

  Moreover, as a polycarbodiimide compound, what was manufactured by the various method can be used. For example, a conventional method for producing polycarbodiimide (US Pat. No. 2,941,956, Japanese Examined Patent Publication No. 47-33279, J.0rg.Chem.28, 2069-2075 (1963), Chemical Review 981, Vol.81 No. 4, p619-621), or those commercially available.

In the present invention, commercially available polycarbodiimide compounds can also be used, such as carbodilite LA-1 and carbodilite HMV-8CA (both manufactured by Nisshinbo Industries, Inc.).
The added amount of the carbodiimide compound is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts by weight, and most preferably 0.1 to 1 part by weight with respect to 100 parts by weight of the lactic acid polymer.

  As a method for adding the carbodiimide compound, any of a method of melt-kneading with a lactic acid polymer in advance and then melt-kneading with a polycarbonate resin or an impact modifier, or a method of melt-kneading simultaneously with a polycarbonate resin or an impact modifier can be suitably used.

[Organic peroxide]
Examples of the organic peroxide include hydroxy peroxide, diacyl peroxide, peroxydicarbonate, peroxyester, peroxymonocarbonate, dialkyl peroxide, ketone peroxide, and peroxyketal. Any of these can be used.
The added amount of the organic peroxide is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts by weight, and most preferably 0.1 to 1 part by weight with respect to 100 parts by weight of the lactic acid polymer.

  As the organic peroxide addition method, it is preferable to use either a method of melt-kneading with a lactic acid polymer in advance and then melt-kneading with a polycarbonate resin or an impact modifier, or a method of melt-kneading simultaneously with a polycarbonate resin or an impact modifier. it can.

  Since the carbodiimide compound and the organic peroxide can improve heat resistance by their addition, they are preferably used when high heat resistance is required.

  For the thermoplastic resin composition of the present invention, resins other than lactic acid polymers and polycarbonate resins, stabilizers (antioxidants, ultraviolet absorbers, light, etc.) within the range that does not impair the purpose of the present invention. Stabilizers, etc.), flame retardants (bromine flame retardants, phosphorus flame retardants, melamine compounds, etc.), lubricants, mold release agents, antistatic agents, surface wetting improvers, colorants including dyes and pigments, nucleating agents (organic) Carboxylic acid metal salts, etc.) and plasticizers, end-capping agents (epoxy compounds, oxazoline compounds), other resins and the like can be added. These additives can be used alone or in combination of two or more.

  For applications that require flame retardancy, it is possible to impart an arbitrary flame retardant level by blending a known flame retardant. Examples of flame retardants include triphenyl phosphate, tricresyl phosphate, resorcinol bis (diphenyl) phosphate, aromatic phosphate esters, aromatic condensed phosphate esters, polyphosphate ammonium phosphates, water Examples of the inorganic flame retardant include aluminum oxide, magnesium hydroxide, zinc borate, molybdenum compound, zinc stannate, silicone compound, and phosphazene compound.

  In the case where fluidity, slipping property, and releasability are required at the time of molding, good fluidity, slipping, and releasability can be imparted by adding a known lubricant. Examples of the lubricant include polyethylene wax, acrylic polymer lubricant, amide compound, bisamide compound, fatty acid ester and the like. Moreover, the impact modifier in this invention and general purpose resin, such as ABS and PS, can be used for the purpose of fluidity | liquidity improvement.

  Known methods can be used for the method for producing the resin composition of the present invention. For example, a method in which a lactic acid polymer, a polycarbonate resin, an impact modifier, a carbodiimide compound, an organic peroxide, an additive and the like are previously blended and then uniformly melt-kneaded using a single-screw or twin-screw extruder may be mentioned. it can. In particular, it is preferable to use a twin screw extruder in order to improve dispersibility.

  The resin composition of the present invention can be suitably used for various known and publicly known molding methods such as injection molding, extrusion molding, calendar molding, blow molding, and rotational molding.

  The preferable physical properties of the injection-molded product obtained using the resin composition obtained by the present invention are a deflection temperature under load of 70 ° C. or higher and 140 ° C. or lower, and an Izod impact strength of 80 J / m or higher and 900 J / m or lower.

  In addition, the deflection temperature shown by this invention shows what measured the deflection temperature (HDT) of thickness 3.2mm under the conditions of 0.45MPa load according to ASTM D648, and Izod impact strength is ASTM D256. The Izod impact strength with a thickness of 3.2 mm was measured at 23 ° C. with a notch according to the above.

  The resin composition obtained by the present invention can be suitably used for various molded articles. For example, it can be used for various office automation equipment such as personal computers, copying machines, mobile phones, digital cameras, televisions, printers, etc.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the present invention, various physical properties were measured and evaluated by the following methods.
(1) Heat resistance According to ASTM D648, the deflection temperature under load (HDT) with a thickness of 3.2 mm was measured under the condition of 0.45 MPa load.
(2) Izod impact strength Izod impact strength of 3.2 mm in thickness was measured at 23 ° C. with a notch in accordance with ASTM D256.
(3) Relative viscosity Relative viscosity is obtained by taking a chloroform solution in which the sample is dissolved in an Ubbelohde viscometer and leaving it in a constant temperature bath maintained at 30 ° C. to bring it to the test temperature. The measurement time was measured, and the ratio was determined by the ratio of the time and the flow time of chloroform.
Relative viscosity RV = t ₁ / t ₀
t ₁ : Sample solution flow time (s)
t ₀ : Flowing time of blank (chloroform) (s)
(4) Crystallinity Crystallinity is the heat of fusion that appears when differential scanning calorimetry (DSC) of polylactic acid heated at 100 ° C. for 4 hours is measured, and is 93 J / g, which is the theoretical crystal melting heat of polylactic acid. It was calculated by dividing by. The DSC measurement condition is 10 ° C./min.
Crystallinity = (Heat of fusion / 93) × 100
(5) Dimensional change The shrinkage rate after a square plate having a length of 150 mm × width 150 mm × 2 mm was left in an oven set at 80 ° C. for 1 hour was measured. The case where the shrinkage rate was 0.5% or less was “no deformation”, and the case where the shrinkage rate was greater than 0.5% was “deformation”.
Shrinkage rate = [{(Dimension before heating) − (Dimension after heating)} / (Dimension before heating)] × 100

Example 1
Polylactic acid (Lacia H-440, standard polystyrene equivalent weight average molecular weight = 210,000, relative viscosity RV = 4.15, crystallinity = 30%, Mitsui Chemicals, Inc.) as a lactic acid polymer, and tuflon (as a polycarbonate resin) ^{# 1700, MVR = 27cm 3 /} 10min, manufactured by Idemitsu Kosan Co.), basic polar functional modified aromatic vinyl-conjugated diene block copolymer with groups as an impact improver (N503,230 ° C. measurement MFR: 20 g / 10 , Specific gravity: 0.91, styrene content: 30 wt%, Asahi Kasei Chemicals Corporation) at a weight ratio of 40: 60: 5, and then a temperature of 220 using a TEM35BS twin screw extruder (Toshiba Machine Co., Ltd.). Melt-kneading was performed at ˜250 ° C. to obtain resin composition pellets. Next, using a Ti-80G2 injection molding machine (Toyo Machine Metal Co., Ltd.), injection molding was performed under conditions of a cylinder set temperature of 220 to 250 ° C., a mold temperature of 40 ° C., and a cooling time of 30 seconds, and a thickness of 3.2 mm. ASTM standard test piece and 150 mm × 150 mm × 2 mm thick square plate were obtained. Table 1 shows the results of measuring the deflection temperature under load (HDT) and the notched Izod impact strength of the obtained test piece. Further, as a result of confirming deformation after the obtained square plate was left in an oven at 80 ° C. for 1 hour, no change was observed.

(Examples 2-4, Comparative Examples 1-2)
The compositions shown in Table 1 were molded and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

The resin composition obtained by the present invention and the molded product obtained therefrom are excellent in impact resistance and heat resistance, can be suitably used for various molded products, and can be used as an exterior material for OA equipment and home appliances. For example, it can be used for various office automation equipment such as personal computers, copying machines, mobile phones, digital cameras, televisions, printers, etc.

Claims (6)

A resin composition comprising 1 to 20 parts by weight of an impact modifier for a total of 100 parts by weight of 1 to 99 parts by weight of a lactic acid polymer having a crystallinity of 0% to 40% and 99 to 1 parts by weight of a polycarbonate resin. . The carbodiimide compound is contained in an amount of 0.1 to 5 parts by weight and / or an organic peroxide is contained in an amount of 0.1 to 5 parts by weight with respect to 100 parts by weight of the total of the lactic acid polymer and the polycarbonate resin. Resin composition. The resin composition according to claim 1, wherein the impact modifier comprises an aromatic vinyl / conjugated diene block copolymer modified with a polar functional group. 4. The aromatic vinyl / conjugated diene block copolymer modified with a polar functional group is an aromatic vinyl / conjugated diene block copolymer modified with a basic functional group. 2. The resin composition according to item 1. SBS (styrene / butadiene / styrene copolymer) modified with imino group, SBBS (styrene / butadiene / butylene) modified with imino group, aromatic vinyl / conjugated diene block copolymer modified with polar functional group 5. A styrene copolymer) or at least one selected from SEBS (styrene / ethylene / butylene / styrene copolymer) modified with an imino group. The resin composition described in 1. The molded object which consists of a resin composition of Claims 1-5.