JP2006137831A - Modified polyester-based thermoplastic elastomer composition and coated article using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the coating adherence of an article of a polyester-based thermoplastic elastomer. <P>SOLUTION: An article body is molded by using a modified polyester-based thermoplastic elastomer composition obtained by modifying a polyester-based thermoplastic elastomer with an unsaturated carboxylic acid and/or its derivative in the presence of a radical generator. Coating is made on the article body. The coating adherence is improved, because the carboxy group introduced into the modified polyester-based thermoplastic elastomer has excellent affinity to the coating. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a modified polyester-based thermoplastic elastomer composition excellent in paintability and a paint molded article using the same.

  Polyester thermoplastic elastomers are excellent in various moldability, mechanical properties, heat resistance, etc., in a wide range of industrial fields such as interior and exterior of transportation equipment such as automobiles and ships, home appliances / office equipment, furniture, daily necessities, sundries, and architecture. It is used as various structural materials.

  These molded articles of thermoplastic resins are often coated for the purpose of protecting the surface, coloring and imparting design properties, and are provided as painted molded articles. However, polyester-based thermoplastic elastomers have low affinity with paints, and therefore, pre-treatment for improving coating film adhesion is required for painting. As these pretreatments, primer treatment, corona discharge treatment and the like are generally known.

  However, the primer treatment requires a high-temperature, long-time drying step for volatilizing the primer treatment agent because it is expensive and contains a large amount of an organic solvent. Moreover, since organic solvents have a problem of environmental pollution, their use is recently regulated. On the other hand, the corona discharge treatment is a method of modifying the surface of the molded body by corona discharge and improving the affinity between the paint and the molded body. However, the applicable molded body is limited in shape and treated. High capital investment for the equipment is required.

  Therefore, if the molded body can be coated directly without performing these pretreatments, it is not necessary to use harmful substances such as organic solvents, and the number of processes can be reduced and capital investment is not required. However, at present, when a polyester thermoplastic elastomer molded body is coated as it is, peeling of the coating film occurs during secondary processing or use.

In addition, the improvement of the coating properties of the polyolefin-based thermoplastic elastomer has been proposed in JP-A-5-331348 and JP-A-6-145440. However, the polyolefin-based thermoplastic elastomer has heat resistance and wear resistance. Because of the lack of mechanical properties such as, application applications are limited.
JP-A-5-331348 JP-A-6-145440

  The present invention is a modified polyester system excellent in paintability that can be applied directly to the surface under good paintability, particularly urethane paint, without performing pretreatment such as primer treatment or corona discharge treatment. It is an object of the present invention to provide a thermoplastic elastomer composition and a coated molded article using the same.

  The modified polyester-based thermoplastic elastomer composition of the present invention (Claim 1) is a modified polyester-based thermoplastic elastomer composition for molding a molded article having a surface coated with the polyester-based thermoplastic elastomer. It is obtained by modifying with an unsaturated carboxylic acid and / or a derivative thereof in the presence of a radical generator.

  The coated molded product of the present invention (Claim 5) is a coated molded product comprising a molded product main body and a coating layer formed on the surface of the molded product main body, and at least the surface layer portion of the molded product main body is polyester. It is characterized by comprising a modified polyester thermoplastic elastomer composition obtained by modifying a thermoplastic elastomer with a unsaturated carboxylic acid and / or a derivative thereof in the presence of a radical generator.

  In the present invention, the polyester-based thermoplastic elastomer is preferably a saturated polyester-based thermoplastic elastomer (Claim 2, Claim 6), and particularly preferably contains a polyalkylene ether glycol segment (Claim 3, Claim). Item 7) The modified polyester thermoplastic elastomer composition of the present invention is obtained by graft polymerization of an unsaturated carboxylic acid and / or a derivative thereof on such a polyester thermoplastic elastomer, and the graft amount is 0.01 to It is preferably 10% by weight (claims 4 and 8).

  The molded product body of the coated molded product of the present invention may be entirely composed of a modified polyester thermoplastic composition (Claim 9), and a substrate and a modified polyester formed on the substrate. And a surface layer made of a thermoplastic elastomer composition (claim 10).

  According to the modified polyester thermoplastic elastomer composition of the present invention, it is possible to obtain a molded article that is remarkably excellent in paintability.

  That is, the modified polyester-based thermoplastic elastomer composition of the present invention includes a composition in which a carboxyl group (—COOH) is introduced into a polyester-based thermoplastic elastomer by modification with an unsaturated carboxylic acid and / or a derivative thereof. The carboxyl group makes the adhesiveness and bondability with the paint stronger, and the paintability is greatly improved as compared with a normal polyester thermoplastic elastomer.

  For this reason, according to the present invention, it is possible to obtain a coated molded article having excellent coating film adhesion by directly coating the surface of the molded article without performing pretreatment such as primer treatment or corona discharge treatment. It is possible to reduce the number of processes related to painting, avoid the use of pretreatment organic solvents, and eliminate the need for capital investment for corona discharge.

  In the case of coated molded products that have a coating film formed without pretreatment, manufacturing costs can be reduced by reducing the pretreatment process, and heat and mechanical stress are applied during secondary processing and use. Even if it is added, the coating film does not peel off, and there is no problem of deterioration in appearance or functionality due to peeling of the coating film, so that it can be effectively applied as various industrial parts.

  However, pre-treatment such as primer treatment and corona discharge treatment is not excluded in the coated molded product of the present invention, and such pre-treatment is also performed prior to painting in the coated molded product of the present invention. By this, it is possible to form a coating film having excellent adhesion with much better paintability.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. However, the description of each constituent element described below is a representative example of embodiments of the present invention, and the present invention is not limited to these unless it exceeds the gist. Is not to be done.

[Modified polyester-based thermoplastic elastomer composition]
The modified polyester thermoplastic elastomer composition of the present invention can be obtained by subjecting an unsaturated carboxylic acid and / or derivative thereof to graft polymerization to a polyester thermoplastic elastomer in the presence of a radical generator and then subjecting it to a modification treatment. In the present invention, the unsaturated carboxylic acid may be an anhydride of an unsaturated carboxylic acid.

[1] Polyester-based thermoplastic elastomer The polyester-based thermoplastic elastomer used in the present invention is preferably a saturated polyester-based thermoplastic elastomer, particularly a saturated polyester-based thermoplastic elastomer containing a polyalkylene ether glycol segment. Is preferred.

  Examples of the polyester-based thermoplastic elastomer include those containing an aromatic polyester as a hard segment and a polyalkylene ether glycol or an aliphatic polyester as a soft segment, and in particular, polyalkylene ether glycol as a soft segment. The polyester polyether block copolymer used is preferred.

  The content of the polyalkylene ether glycol component in the polyester polyether block copolymer is usually 5 to 90% by weight, preferably 30 to 80% by weight, and more preferably 55 to 80% by weight. When the content of the polyalkylene ether glycol component in the polyester polyether block copolymer exceeds 90% by weight, sufficient hardness may not be expressed in the obtained molded product, and the mechanical strength may be inferior. When the content is less than 5% by weight, the elastomeric properties are lowered, and the flexibility and impact resistance may be insufficient. The content of the polyalkylene ether glycol component in the polyester polyether block copolymer can be calculated based on the chemical shift of the hydrogen atom and its content using NMR.

As a polyester polyether block copolymer suitable for the present invention,
(I) a diol component comprising an aliphatic and / or alicyclic diol having 2 to 12 carbon atoms;
(Ii) a carboxylic acid component selected from aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and alkyl esters thereof;
(Iii) Polyalkylene ether glycol as a raw material and those obtained by polycondensation of oligomers obtained by esterification reaction or transesterification reaction may be mentioned.

  As the (i) C2-C12 aliphatic and / or alicyclic diol, those generally used as a raw material for polyester, particularly as a raw material for a polyester-based thermoplastic elastomer, can be used. Specific examples thereof include ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and the like. Among these, 1,4-butanediol or ethylene glycol is preferable, and 1,4-butanediol is particularly preferable. These diol components may be used individually by 1 type, and may use 2 or more types together.

  As the aromatic dicarboxylic acid (ii), those generally used as raw materials for polyesters, particularly polyester thermoplastic elastomers, can be used. Specific examples thereof include terephthalic acid, isophthalic acid, phthalic acid, and 2,6-naphthalenedicarboxylic acid. Among these, terephthalic acid or 2,6-naphthalenedicarboxylic acid is preferable, and terephthalic acid is particularly preferable.

  As the alkyl ester of the aromatic dicarboxylic acid, alkyl esters such as dimethyl ester and diethyl ester of the above aromatic dicarboxylic acid are used. Of these, dimethyl terephthalate and 2,6-dimethyl naphthalene dicarboxylate are preferable.

  The aliphatic dicarboxylic acid is preferably cyclohexane dicarboxylic acid, and the alkyl ester is preferably an alkyl ester such as dimethyl ester or diethyl ester.

  These carboxylic acid components may be used individually by 1 type, or may be used in combination of 2 or more type.

  As the polyalkylene ether glycol (iii), those having a number average molecular weight of usually 400 to 6,000, preferably 500 to 4,000, more preferably 600 to 3,000 are used. When the number average molecular weight of the polyalkylene ether glycol is less than 400, the resulting polyester polyether block copolymer has insufficient block properties. When the number exceeds 6,000, phase separation in the system is likely to occur. There is a tendency that the physical properties of the obtained polymer are lowered. Here, the number average molecular weight refers to that measured by gel permeation chromatography (GPC). For the calibration of GPC, a POLYTETRAHYDROFURAN calibration kit manufactured by POLYMER LABORATORIES, UK may be used.

  Specific examples of the polyalkylene ether glycol include polyethylene glycol, poly (1,2-propylene ether) glycol, poly (1,3-propylene ether) glycol, poly (tetramethylene ether) glycol, poly (hexamethylene ether). ) Glycol and the like.

  These polyalkylene ether glycols may be used alone or in combination of two or more.

  The polyester polyether block copolymer may be obtained by copolymerizing a small amount of one or more of trifunctional alcohols and tricarboxylic acids and / or esters thereof in addition to the components (i) to (iii). In addition, aliphatic dicarboxylic acids such as adipic acid and dialkyl esters thereof may also be introduced as a copolymerization component.

  Commercially available products may be used as the polyester-based thermoplastic elastomer comprising the polyester polyether block copolymer suitable for the present invention. For example, “Primalloy” manufactured by Mitsubishi Chemical Corporation, “Perprene” manufactured by Toyobo Co., Ltd. And “Hytrel” manufactured by Toray DuPont Co., Ltd.

[2] Unsaturated carboxylic acid and derivatives thereof (hereinafter referred to as “unsaturated carboxylic acid component”)
As the unsaturated carboxylic acid component used in the present invention, α, β-ethylenically unsaturated carboxylic acid or its anhydride is preferable, for example, acrylic acid, maleic acid, fumaric acid, tetrahydrofumaric acid, itaconic acid, citraconic acid, Unsaturated carboxylic acids such as crotonic acid and isocrotonic acid; succinic acid 2-octen-1-yl anhydride, succinic acid 2-dodecen-1-yl anhydride, succinic acid 2-octadecen-1-yl anhydride, maleic acid Anhydride, 2,3-dimethylmaleic anhydride, bromomaleic anhydride, dichloromaleic anhydride, citraconic anhydride, itaconic anhydride, 1-butene-3,4-dicarboxylic anhydride, 1- Cyclopentene-1,2-dicarboxylic anhydride, 1,2,3,6-tetrahydrophthalic anhydride, 3,4,5,6-tetrahydrophthal Acid anhydride, exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic acid anhydride, methyl-5-norbornene-2,3-dicarboxylic acid Acid anhydride, endo-bicyclo [2.2.2] oct-5-ene-2,3-dicarboxylic acid anhydride, bicyclo [2.2.2] oct-7-ene-2,3,5,6 -Unsaturated carboxylic acid anhydrides, such as tetracarboxylic acid anhydride.

  Examples of the derivatives of α, β-ethylenically unsaturated carboxylic acids include the above α, β-ethylenically unsaturated carboxylic acids or esterified products of the anhydrides. Specifically, the α, β- Examples thereof include an ethylenically unsaturated carboxylic acid or its anhydride methyl ester or ethyl ester.

  These unsaturated carboxylic acid components can be appropriately selected according to the polyester-based thermoplastic elastomer to be modified and the modification conditions, and are not limited to being used alone, but may be used in combination of two or more. .

  The unsaturated carboxylic acid component can also be used by dissolving in an organic solvent or the like.

[3] Radical generator As the radical generator used in the present invention, for example, t-butyl hydroperoxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2, 5-dimethyl-2,5-bis (tertiarybutyloxy) hexane, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxybenzoate, benzoyl peroxide, m-toluoyl peroxide, dicumyl Organic and inorganic peroxides such as peroxide, 1,3-bis (t-butylperoxyisopropyl) benzene, dibutyl peroxide, methyl ethyl ketone peroxide, potassium peroxide, hydrogen peroxide; 2,2'-azobis Isobutyronitrile, 2,2'-azobis (isobutyla And azo compounds such as azodi-t-butane; carbon radical generators such as dicumyl; and the like.

  The radical generator can be appropriately selected according to the type of polyester-based thermoplastic elastomer used in the modification reaction, the type of unsaturated carboxylic acid component and the modification conditions, and one type may be used alone. Two or more kinds may be used in combination.

  The radical generator can be used after being dissolved in an organic solvent.

[4] Modification Reaction As the modification reaction for obtaining the modified polyester thermoplastic elastomer composition of the present invention, various known reaction methods such as a melt-kneading reaction method, a solution reaction method, and a suspension dispersion reaction method are used. However, the melt-kneading reaction method is usually preferable.

  In the case of the melt-kneading reaction method, the components described above may be melt-kneaded after being uniformly mixed at a predetermined blending ratio. For mixing, a Henschel mixer, a ribbon blender, a V-type blender, or the like is used. For melt kneading, a Banbury mixer, a kneader, a roll, a multi-screw kneading extruder such as a single screw or a twin screw is used. Further, an active hydrogen compound described later and other optional components may be supplied from the middle and melt kneaded.

  The melt-kneading is usually performed in a range of 100 ° C. to 300 ° C., preferably 120 ° C. to 280 ° C., and more preferably 150 ° C. to 250 ° C. so that the resin is not thermally degraded.

  The amount of the unsaturated carboxylic acid component as a modifier for the polyester-based thermoplastic elastomer is usually 0.01 to 30 parts by weight, preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the polyester-based thermoplastic elastomer. More preferably, it is 0.1 to 1 part by weight. When the amount of the unsaturated carboxylic acid component is less than 0.01 part by weight based on 100 parts by weight of the polyester-based thermoplastic elastomer, sufficient modification cannot be performed. When the amount exceeds 30 parts by weight, the amount depends on the amount. A modification rate cannot be obtained, which is uneconomical.

  Moreover, the compounding quantity of a radical generator is 0.001-3 weight part normally with respect to 100 weight part of polyester-type thermoplastic elastomers, Preferably it is 0.005-0.5 weight part, More preferably, it is 0.01-0. .2 parts by weight, particularly preferably 0.01 to 0.1 parts by weight. When the blending amount of the radical generator is less than 0.001 part by weight with respect to 100 parts by weight of the polyester thermoplastic elastomer, the modification does not occur sufficiently, and when it exceeds 3 parts by weight, the modification of the polyester thermoplastic elastomer Lowering the molecular weight (decrease in viscosity) at the time is large, and the material strength is significantly reduced. That is, in this modification reaction, a graft polymerization reaction in which an unsaturated carboxylic acid component is added to a polyester-based thermoplastic elastomer mainly occurs, but a decomposition reaction also occurs, and the modified polyester-based thermoplastic elastomer composition obtained by the decomposition is: The molecular weight is lowered and the melt viscosity is lowered. If the amount of the radical generator used is too large, a graft polymerization reaction is likely to occur, but at the same time, a decomposition reaction that leads to a decrease in melt viscosity is likely to occur.

[5] Modified polyester-based thermoplastic elastomer-containing reaction product As described above, in the modification treatment of a polyester-based thermoplastic elastomer with an unsaturated carboxylic acid component in the presence of a radical generator, the polyester-based thermoplastic elastomer is converted into an unsaturated carboxylic acid. In addition to the graft polymerization reaction in which the components are added, a transesterification reaction or the like may occur as a decomposition reaction or other reaction. For this reason, the reaction product obtained is generally a modified polyester thermoplastic elastomer composition containing unreacted raw materials and reaction byproducts together with the modified polyester thermoplastic elastomer. The content of the modified polyester thermoplastic elastomer in the reaction product is usually 10% by weight or more, preferably 30% by weight or more, but the reaction product may be a modified polyester thermoplastic elastomer alone.

  This reaction product, that is, the modified polyester thermoplastic elastomer composition of the present invention can be directly used for molding as described later.

  In the present invention, the JIS-D hardness (the hardness according to durometer type D according to JIS-K6253) of the modified polyester thermoplastic elastomer composition obtained by the modification treatment of the polyester thermoplastic elastomer is usually 10 to 80, preferably 15 It is -70, More preferably, it is 20-60. When the JIS-D hardness is less than 20, the mechanical strength of a molded product obtained using this modified polyester thermoplastic elastomer composition tends to be inferior. When it exceeds 60, the flexibility and impact resistance are inferior. There is.

  The modification rate (graft amount) of the modified polyester thermoplastic elastomer composition is usually 0.01 to 10% by weight, preferably 0.03 to 7% by weight, more preferably 0.05 to 5% by weight. . When the graft amount is less than 0.01% by weight, the coating properties cannot be improved because the functional group is too small. When the graft amount exceeds 10% by weight, the material strength decreases due to molecular degradation during the modification process. End up.

The modification rate (graft amount) of the modified polyester-based thermoplastic elastomer composition can be determined according to the following formula from the spectrum obtained by H ¹ -NMR measurement. As an apparatus used for the H ¹ -NMR measurement, for example, “GSX-400” manufactured by JEOL Ltd. can be used.

（但し、式中のＡは７．８〜８．４ｐｐｍの積分値、Ｂは１．２〜２．２ｐｐｍの積分値、Ｃは２．４〜２．９ｐｐｍの積分値である。）

(However, A is an integral value of 7.8 to 8.4 ppm, B is an integral value of 1.2 to 2.2 ppm, and C is an integral value of 2.4 to 2.9 ppm.)

[Forming raw materials]
In the present invention, the modified polyester-based thermoplastic elastomer composition as a molding raw material is a resin component other than the modified polyester-based thermoplastic elastomer-containing reaction product obtained by the above-described modification reaction within a range not departing from the gist of the present invention. Or other rubber components or other components such as fillers and various additives. For example, rubber components such as natural rubber and synthetic rubber (for example, polyisoprene rubber) and softeners such as process oil may be blended. The softening agent is added for the purpose of promoting plasticization of the rubber component and improving the fluidity of the resulting composition. These may be paraffinic, naphthenic, or aromatic.

  As filler, calcium carbonate, talc, silica, kaolin, clay, diatomaceous earth, calcium silicate, mica, asbestos, alumina, barium sulfate, aluminum sulfate, calcium sulfate, magnesium carbonate, carbon fiber, glass fiber, glass bulb, molybdenum sulfide, Examples thereof include graphite and shirasu balloons.

  Examples of the additive include a heat resistance stabilizer, a weather resistance stabilizer, a colorant, an antistatic agent, a flame retardant, a nucleating agent, a lubricant, a slip agent, and an antiblocking agent. Known heat-resistant stabilizers such as phenol-based, phosphorus-based, and sulfur-based stabilizers can be used. Further, as the weather resistance stabilizer, known ones such as hindered amines and triazoles can be used. Examples of the colorant include carbon black, titanium white, zinc white, red pepper, azo compound, nitroso compound, and phthalocyanine compound. Known antistatic agents, flame retardants, nucleating agents, lubricants, slip agents, antiblocking agents and the like can be used.

[Coated molded products]
The coated molded product of the present invention has a coating layer formed by coating on the surface of the molded product body.

  The molded article main body according to the present invention includes the modified polyester-based thermoplastic elastomer composition of the present invention, that is, the above-mentioned modified polyester-based thermoplastic elastomer-containing reaction product, if necessary, other rubber components, resin components, and fillers. In addition, an additive and the like can be obtained by molding into a desired shape such as a film, a sheet, a container or a box by extrusion molding, injection molding, vacuum molding, hollow molding or the like according to a conventional method. Moreover, the film and the sheet may be stretched. Further, the molded product body according to the present invention has the modified polyester thermoplastic elastomer molded product thus obtained as a surface layer, polyethylene, polypropylene, ethylene / vinyl acetate copolymer, polyamide, polybutylene terephthalate, polyethylene terephthalate. Further, a laminated structure in which a molded article made of one or two or more thermoplastic resins such as polyphenylene sulfide, polyphenylene ether, and polycarbonate is used as a base may be used. Such a laminate may be integrally molded by two-layer molding or the like, or may be separately molded and bonded by adhesion or fusion.

  By coating such a molded product body, the coated molded product of the present invention can be obtained. Examples of paints used for painting include paints that are widely used, such as acrylic paints, epoxy paints, polyester paints, urethane paints, alkyd paints, and melamine paints. Among these, acrylic paints, polyester paints, urethane paints, particularly urethane paints are preferable because they have high affinity with the functional groups of the modified polyester thermoplastic elastomer and have better adhesion. These paints may be either a two-component type or a one-component type.

  As a method for applying such a coating material to the molded article body, a commonly used method can be adopted, for example, a method using a spray gun, a method by brush coating, a method using a roll coater or the like.

  The thickness of the coating film can be changed according to the purpose of use of the coated molded article and is not particularly limited, but is usually in the range of 1 to 500 μm after drying.

  In addition, you may apply | coat a coating material further on the coating film formed with the said coating material. Examples of the top coat include acrylic paint, fluorine paint, silicon paint, alkyd paint, and the like.

  As described above, by using the modified polyester thermoplastic elastomer composition of the present invention, excellent coating film adhesion can be obtained without pretreatment such as primer treatment or corona discharge treatment. In the present invention, when coating the molded product body, these pre-treatments can be omitted to reduce the painting process and improve the working environment. In the present invention, however, before the primer treatment, corona discharge treatment, etc. The treatment is not excluded, and by performing these pretreatments, it is possible to obtain even better coating film adhesion.

The coated molded product of the present invention has a coating layer on the surface, so that the appearance, design, and physical properties of the surface are greatly improved.
In addition, there is no restriction | limiting in particular in the shape of the molded product main body of the coating molded product of this invention, A sheet form, plate shape, a container or box shape, and other various shapes can be employ | adopted. In addition, when the molded product body has a laminated structure having a surface layer made of a modified polyester thermoplastic elastomer composition and a substrate, the shape of the substrate and the surface layer is not particularly limited. And preferably have a thickness of at least 5 μm.

  Such coated molded articles of the present invention include various industrial parts such as automobile exterior parts such as automobile bumpers, corner bumpers, bumper air dam skirts, mudguards, side moldings, wheel caps, spoilers, side steps, door mirror bases, etc. Automotive interior parts such as instrument panels, levers, knobs, dashboards, door liners, connectors, jack covers, cap plugs, pots, refrigerators, lighting equipment, audio equipment, OA equipment, etc., electrical boxes, color boxes, storage cases It is extremely useful industrially as daily miscellaneous goods such as.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the following, the raw materials used and various measuring methods are as follows.
(1) Polyester-based thermoplastic elastomer A: Polyester polyethylene having a hard segment of polybutylene terephthalate, a soft segment of polytetramethylene ether glycol having a number average molecular weight of 2000, and a poly (tetramethylene ether) glycol content of 65% by weight Ether block copolymer (flexural modulus: 35.5 MPa, density: 1.09 g / cm ³ , melting peak temperature by differential scanning calorimeter: 185 ° C., JIS-D hardness: 34)
(2) Polyester-based thermoplastic elastomer B: Polybutylene terephthalate with a hard segment, polytetramethylene ether glycol with a soft segment having a number average molecular weight of 1000, and a poly (tetramethylene ether) glycol content of 35% by weight Ether block copolymer (flexural modulus: 200 MPa, density: 1.20 g / cm ³ , melting peak temperature by differential scanning calorimeter: 205 ° C., JIS-D hardness: 55)
(3) Unsaturated carboxylic acid component: “Maleic anhydride reagent special grade” manufactured by Wako Pure Chemical Industries, Ltd.
(4) Radical generator: m-toluoyl peroxide / benzoyl peroxide mixture (“Nyper BMT-K40” manufactured by NOF Corporation)
(5) Graft amount of the modified polyester-based thermoplastic elastomer: H ^1- NMR (“GSX-400” manufactured by JEOL Ltd.) is used, and a mixed solvent of HFIP (hexafluoroisopropanol) and CDCl ₃ (deuterium chloroform) is used. It was calculated | required by the above-mentioned calculation formula from the spectrum obtained by using.
(6) Adhesion evaluation: In accordance with JIS-K5400, a cross-cut tape peeling test was conducted under the conditions of 2 mm square, peeling angle of 45 degrees, and the number of peeling times of 15, and after the peeling test, the presence or absence of peeling and the number of peelings were examined. .

Example 1
0.5 parts by weight of unsaturated carboxylic acid component and 0.05 parts by weight of radical generator are mixed with 100 parts by weight of polyester-based thermoplastic elastomer A, and this is mixed with “PCM-45 type kneader” (Diameter) 44 mm, temperature 190 to 220 ° C.) and then kneaded and pelletized through a pelletizer to produce a modified polyester thermoplastic elastomer composition. The graft amount of this modified polyester thermoplastic elastomer composition was 0.3% by weight. The obtained modified polyester thermoplastic elastomer composition had a JIS-D hardness of 34, and the content of the modified polyester thermoplastic elastomer contained in the composition was 45% by weight.

  The pellets were press-molded to form a sheet having a length of 100 mm, a width of 100 mm, and a thickness of 1 mm. On this sheet, urethane paint manufactured by Ohashi Chemical Industry: 800 and E-70, no. A paint having a blend of 7400 in a ratio of 4 to 1: 4 (volume ratio) was applied using a spray gun to form a coating film having a thickness of 100 μm. The evaluation results of the adhesion of this coating film are shown in Table 1.

Example 2
A modification reaction was carried out in the same manner as in Example 1 except that the addition amount of the unsaturated carboxylic acid component was changed to 0.25 parts by weight and the addition amount of the radical generator was changed to 0.13 parts by weight. The modified polyester-based thermoplastic elastomer composition had a graft amount of 0.15% by weight, a JIS-D hardness of 33, and the content of the modified polyester-based thermoplastic elastomer contained in the composition was 28% by weight. there were.

  Using this pellet, molding and coating were performed in the same manner as in Example 1, and the results of evaluating the adhesion of the formed coating film are shown in Table 1.

Example 3
When the modification reaction was carried out in the same manner as in Example 1 except that the polyester thermoplastic elastomer B was used instead of the polyester thermoplastic elastomer A, the graft amount of the resulting modified polyester thermoplastic elastomer composition was as follows. At 0.3% by weight, the JIS-D hardness was 55, and the content of the modified polyester thermoplastic elastomer contained in the composition was 45% by weight.

  Using this pellet, molding and coating were performed in the same manner as in Example 1, and the results of evaluating the adhesion of the formed coating film are shown in Table 1.

Comparative Example 1
The polyester-based thermoplastic elastomer A is not modified, the polyester-based thermoplastic elastomer A is pelletized as it is, molded and coated in the same manner as in Example 1, and the evaluation results of the adhesion of the formed coating film are shown in Table 1. It was shown to.

Comparative Example 2
The polyester-based thermoplastic elastomer B is not modified, the polyester-based thermoplastic elastomer B is pelletized as it is, molded and coated in the same manner as in Example 1, and the evaluation results of the adhesion of the formed coating film are shown in Table 1. It was shown to.

  From Table 1, it can be seen that the coating film adhesion is improved according to the present invention.

Claims (10)

  A modified polyester-based thermoplastic elastomer composition for molding a molded article having a surface coated thereon, wherein the polyester-based thermoplastic elastomer is treated with an unsaturated carboxylic acid and / or a derivative thereof in the presence of a radical generator. A modified polyester thermoplastic elastomer composition obtained by a modification treatment.   2. The polyester thermoplastic elastomer composition according to claim 1, wherein the polyester thermoplastic elastomer is a saturated polyester thermoplastic elastomer.   3. The modified polyester thermoplastic elastomer composition according to claim 1, wherein the polyester thermoplastic elastomer contains a polyalkylene ether glycol segment.   4. The polyester thermoplastic elastomer according to any one of claims 1 to 3, wherein the unsaturated carboxylic acid and / or derivative thereof is graft-polymerized, and the graft amount is 0.01 to 10% by weight. A modified polyester thermoplastic elastomer composition characterized by the above. In a coated molded product comprising a molded product body and a coating layer formed on the surface of the molded product body,
At least the surface layer portion of the molded article body is composed of a modified polyester thermoplastic elastomer composition obtained by modifying a polyester thermoplastic elastomer with an unsaturated carboxylic acid and / or a derivative thereof in the presence of a radical generator. Painted molded product characterized by that.   The coated molded article according to claim 5, wherein the polyester-based thermoplastic elastomer is a saturated polyester-based thermoplastic elastomer.   The coated molded article according to claim 5 or 6, wherein the polyester-based thermoplastic elastomer contains a polyalkylene ether glycol segment.   8. The polyester thermoplastic elastomer composition according to claim 5, wherein the polyester thermoplastic elastomer is obtained by graft polymerization of the unsaturated carboxylic acid and / or a derivative thereof on the polyester thermoplastic elastomer. A coated molded product characterized by being 0.01 to 10% by weight.   9. The coated molded article according to any one of claims 5 to 8, wherein the molded article main body is entirely made of the modified polyester thermoplastic elastomer composition.   9. The coating according to claim 5, wherein the molded article body has a base and a surface layer made of the modified polyester thermoplastic elastomer composition formed on the base. Molding.