JP2010254770A - Interior material for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an interior material which has an excellent biodegradation characteristic and can easily be recycled at a low cost, for example, by chemical recycling. <P>SOLUTION: When a thermoplastic polyurethane resin having ester bonds in the molecule among thermoplastic polyurethane resins is mixed with an aliphatic polyester resin having a carboxylic acid at the terminal, the acid point originated from the aliphatic polyester resin can hydrolyze the ester bond in the thermoplastic polyurethane resin. Consequently, the thermoplastic polyurethane resin can be converted into low molecules. The interior material for the vehicles comprises the thermoplastic polyurethane resin having ester bonds in the molecule and the aliphatic polyester resin having the carboxylic acid at the terminal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle interior material molded and processed with a composition containing a thermoplastic polyurethane resin.

  In recent years, recycling of various resin products has been required as part of environmental protection measures, and it is also required to improve the recyclability of vehicle interior materials such as skin parts such as instrument panels and door trims. Here, the recyclability means the ease of recycling, and specifically means that the molecular weight is reduced in a short time and / or at a low cost.

  The thermoplastic polyurethane resin is hydrolyzed under high temperature and high humidity conditions. Therefore, as disclosed in Patent Document 1, a resin composition containing a thermoplastic polyurethane resin has attracted attention as an interior material for vehicles excellent in recyclability. However, a vehicle interior material using a resin composition containing a thermoplastic polyurethane resin has a long standing time under high temperature and high humidity, and it has been difficult to put it into practical use as an excellent recyclable material.

  On the other hand, a biodegradable film or the like uses a resin composition containing a polyurethane resin and an aliphatic polyester resin or polyvinyl chloride (Patent Document 2). However, the resin composition as disclosed in Patent Document 2 has a problem that it cannot be used as a vehicle interior material because of insufficient strength and poor moldability.

Japanese Patent No. 3492574 Japanese Patent Publication No. 7-740

  As described above, in a molded article using a resin composition containing a thermoplastic polyurethane resin, it is difficult to achieve both recyclability and strength. A vehicle interior material using a resin composition that satisfies these requirements is It was not known. Therefore, the present invention contains a resin having a polyurethane structure, is excellent in biodegradability, and can be easily recycled at a low cost, for example, by chemical recycling, and can achieve excellent strength. It aims at providing the interior material for vehicles using a thing.

  As a result of intensive studies by the present inventors in order to achieve the above object, among thermoplastic polyurethane resins, a thermoplastic polyurethane resin having an ester bond in the molecule and an aliphatic polyester resin having a carboxylic acid at the terminal are mixed. Thus, it has been found that the acid sites derived from the aliphatic polyester resin can hydrolyze the ester bond in the thermoplastic polyurethane resin, and as a result, the thermoplastic polyurethane resin can be reduced in molecular weight, thereby completing the present invention. It came to.

  That is, the vehicle interior material according to the present invention includes a thermoplastic polyurethane resin containing an ester group and an aliphatic polyester resin having a carboxylic acid at the terminal.

  In particular, the interior material for a vehicle according to the present invention has a composition ratio of the thermoplastic polyurethane resin or the thermoplastic polyurethane resin composition containing the thermoplastic polyurethane resin and an additive and the aliphatic polyester resin in terms of weight. It is preferable that it is 95: 5-80: 20.

  Further, in the vehicle interior material according to the present invention, in the composition containing the thermoplastic polyurethane resin and the aliphatic polyester resin, the concentration of the ester group derived from the aliphatic polyester resin is 0.7 to 2.8 mol / kg. Preferably there is.

  As the aliphatic polyester resin, polyhydroxyalkanoic acid can be used, and polylactic acid is particularly preferably used. Moreover, the vehicle interior material according to the present invention can be molded by slush molding.

  ADVANTAGE OF THE INVENTION According to this invention, the interior material for vehicles which contains a thermoplastic polyurethane resin, is excellent in a biodegradation characteristic, and was excellent in intensity | strength can be provided. By using the vehicle interior material according to the present invention, it is possible to provide a molded article that has excellent biodegradability and can be recycled at low cost. In particular, according to the vehicle interior material according to the present invention, the mechanical properties inherent to the thermoplastic polyurethane resin can be maintained.

It is a characteristic view which shows the relationship between the composition ratio of the aliphatic polyester resin in a slush molding, and tear strength retention. It is a characteristic view which shows the relationship between the composition ratio of the aliphatic polyester resin in a slush molded object, and tearing physical property. It is a characteristic view which shows the relationship between the ester group density | concentration derived from the aliphatic polyester resin contained in a resin composition, and a decomposition rate.

  Hereinafter, the vehicle interior material according to the present invention will be described in more detail. The vehicle interior material according to the present invention includes a thermoplastic polyurethane resin containing an ester group and an aliphatic polyester resin having a carboxylic acid at the terminal. The vehicle interior material according to the present invention may be manufactured from a resin composition in which the polyurethane resin and the aliphatic polyester resin are mixed in the form of a powder, or a resin composition that is pelletized after both are melt-mixed. May be manufactured from. Hereinafter, each component will be described in detail.

Thermoplastic polyurethane resin having an ester bond The thermoplastic polyurethane resin having an ester bond means, for example, a polymer compound in which a diisocyanate component and a polyester diol component are bonded by a urethane bond. For example, in a reaction system containing a diisocyanate component and a polyester diol component, a chain extender (diol, for example, 1,4-butylene glycol and / or a diamine such as ethylenediamine) and, if necessary, a reaction terminator (monohydric alcohol, primary or secondary). A thermoplastic polyurethane resin having an ester bond can be produced by adding and reacting a secondary monoamine or mono- or di-alkanolamine). In addition, when manufacturing a thermoplastic polyurethane resin having an ester bond, any method selected from a so-called prepolymer method, one-shot method, semipolymer method, and pseudo-prepolymer method may be applied.

  Here, although it does not specifically limit as diisocyanate, C6-C20 aromatic diisocyanate, C2-C18 aliphatic diisocyanate, C4-C15 (it removes the carbon in a NCO group, and so on) Cycloaliphatic diisocyanates, araliphatic diisocyanates having 8 to 15 carbon atoms, modified products of these diisocyanates, and mixtures of two or more thereof can be used. Specific examples include those described in International Publication WO00 / 47652.

  The polyester diol is not particularly limited, and is obtained by reacting a diol (low molecular diol and / or polyoxyalkylene diol having a molecular weight of 1000 or less) with a dicarboxylic acid or an ester-forming derivative thereof, or a dicarboxylic acid anhydride and an alkylene oxide. Obtained by reacting a low molecular weight diol with a carbonic acid diester of a lower alcohol (1 to 4 carbon atoms). Polycarbonate diol and the like are included.

  Examples of the polyester diol include (1) condensation polyester diol, (2) polylactone diol, (3) polycarbonate diol, and combinations of two or more of these. The (1) condensed polyester diol includes, for example, one or more diols (low molecular diols and / or polyether diols) and dicarboxylic acids or ester-forming derivatives thereof [lower alkyl (C1 to C4) esters, acid anhydrides. Products, halides (chlorides, etc.)], or reaction of diols with dicarboxylic anhydrides and alkylene oxides. The (2) polylactone diol is obtained by ring-opening polymerization of a lactone using one or more of the diols as an initiator. Said (3) polycarbonate diol can be manufactured by reaction of the said diol and alkylene carbonate (ethylene carbonate).

  Among the raw diols for the above (1), (2) and (3), examples of the low molecular diol include aliphatic low molecular diols (ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1 , 6-hexanediol, etc.]; low molecular diols having a cyclic group [for example, those described in JP-B No. 45-1474: 1,4-bis (hydroxymethyl) cyclohexane, m- or p-xylylene glycol, etc. ], Alkylene oxide low-mole adducts of bisphenols (number average molecular weight of less than 500); and combinations of two or more thereof. Examples of polyether diols include the polyether diols described above. One or more types can be mentioned. Preference is given to 1,4-butanediol and 1,6-hexanediol.

  Examples of the raw material dicarboxylic acid for (1) above include, for example, aliphatic dicarboxylic acids having 2 to 10 carbon atoms (succinic acid, adipic acid, sebacic acid, glutaric acid, azelaic acid, maleic acid, fumaric acid, etc.), carbon Examples thereof include aromatic dicarboxylic acids of several 8 to 12 (terephthalic acid, isophthalic acid, etc.) and combinations of two or more of these.

  Preferable examples of the above (1) include, for example, polybutylene adipate diol and polyhexamethylene isophthalate diol (hereinafter abbreviated as PBA and PHIP, respectively) and combinations thereof. Examples of the raw material lactone for the above (2) include γ-butyrolactone, γ-valerolactone, ε-caprolactone, and combinations of two or more thereof.

  In the thermoplastic polyurethane resin having an ester bond, the ester bond is preferably 5.4 to 7.6 mol / kg, and more preferably 6.3 to 7.5 mol / kg. When the ester bond content is below the above range, the biodegradation characteristics of the vehicle interior material may be excessively lowered. Moreover, when content of an ester bond exceeds the said range, there exists a possibility that durability of a vehicle interior material may deteriorate.

  The weight average molecular weight of the thermoplastic polyurethane resin having an ester bond is not particularly limited, but is preferably 30,000 to 300,000, more preferably 50,000 to 280,000, and most preferably 80,000 to 250,000. . Here, the weight average molecular weight means a molecular weight in terms of polystyrene measured by gel permeation chromatography after dissolving a measurement sample in dimethylformamide.

  Furthermore, as a thermoplastic polyurethane resin having an ester bond, it can also be used as a composition containing an additive. Here, examples of the additive include known and commonly used pigments, plasticizers, mold release agents, dispersants, inorganic fillers, organic fillers, stabilizers, ultraviolet absorbers (light stabilizers), antioxidants, and the like. Can be mentioned. As for the compounding quantity of these additives in a composition, 0-34 weight part is preferable with respect to 100 weight part of thermoplastic polyurethane resins, More preferably, it is 0.05-20 weight part.

The aliphatic polyester resin is not particularly limited as long as it is a compound in which at least one of the molecular chains, preferably both ends are carboxyl groups, and an acid point is generated by hydrolysis. Examples of aliphatic polyester resins include ring-opening polyaddition aliphatics such as polylactic acid, polyglycolic acid, poly (3-hydroxybutyric acid), poly (4-hydroxybutyric acid), poly (4-hydroxyvaleric acid), and polycaprolactone. Polyester, as well as polyester carbonate, polyethylene succinate, polybutylene succinate, polyhexamethylene succinate, polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polyethylene oxalate, polybutylene oxalate, polyhexamethylene oxalate, polyethylene Examples thereof include polycondensation reaction type aliphatic polyesters such as sebacate and polybutylene sebacate. In particular, as the aliphatic polyester resin, poly (α-hydroxy acid) such as polylactic acid and polyglycolic acid is preferable, and polyhydroxyalkanoic acid such as polylactic acid and polyhydroxybutyric acid is particularly preferable.

  The weight average molecular weight of the aliphatic polyester resin is preferably 80,000 to 300,000, more preferably 100,000 to 200,000, and most preferably 120,000 to 170,000. If the weight average molecular weight of the aliphatic polyester is less than 80,000, mechanical properties such as strength and elastic modulus of the obtained molded article may be insufficient.

  When the aliphatic polyester resin is mainly polylactic acid, the constituent molar ratio L / D of the L-lactic acid unit and the D-lactic acid unit in the polylactic acid may be any of 100/0 to 0/100. However, in order to obtain a high melting point, the unit of either L-lactic acid or D-lactic acid is 96 mol% or more, and in order to obtain a higher melting point, the unit of either L-lactic acid or D-lactic acid is 98 mol. % Or more is particularly preferable. The polymer having a lactic acid unit in that case may be a copolymer obtained by copolymerizing lactic acid (monomer) or another component copolymerizable with lactide. Examples of other copolymerizable components include dicarboxylic acids having two or more ester bond-forming functional groups, polyhydric alcohols, hydroxycarboxylic acids, lactones, and various polyesters and various polyesters composed of these various components. Examples include ether and various polycarbonates.

  Examples of the dicarboxylic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid and the like. Examples of polyhydric alcohols include aromatic polyhydric alcohols such as those obtained by addition reaction of bisphenol with ethylene oxide, ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol, glycerin, sorbitan, trimethylolpropane, neo Examples include aliphatic polyhydric alcohols such as pentyl glycol, ether glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, and polypropylene glycol.

  Examples of the hydroxycarboxylic acid include glycolic acid, hydroxybutylcarboxylic acid, and others described in JP-A-6-184417. Examples of lactones include glycolide, ε-caprolactone glycolide, ε-caprolactone, ε-propiolactone, δ-butyrolactone, β-butyrolactone, γ-butyrolactone, pivalolactone, δ-valerolactone, and the like. Further, the arrangement pattern of the copolymer may be any of a random copolymer, an alternating copolymer, a block copolymer, and a graft copolymer.

  The aliphatic polyester resin may be the above-described aliphatic polyester alone, but may be a blend or copolymer of two or more thereof. Examples of such an aliphatic polyester copolymer include a copolymer of lactic acid and a hydroxy acid other than lactic acid, polybutylene succinate adipate, and the like. Further, the arrangement pattern of the copolymer may be any of a random copolymer, an alternating copolymer, a block copolymer, and a graft copolymer.

  As the blend of the aliphatic polyester, for example, a polylactic acid-based resin based on polylactic acid is preferable, and as the other resin blended with the polylactic acid, the aliphatic polyester other than polylactic acid; polyethylene terephthalate, polybutylene terephthalate Aromatic polyesters such as nylon 6, nylon 6,6, nylon 6,9, nylon 6,10, nylon 6,12, nylon 11, nylon 12, and the like.

  In particular, the concentration of ester groups contained in the aliphatic polyester resin is preferably 0.7 to 2.8 mol / kg. When the concentration of the ester group contained in the aliphatic polyester resin is in this range, the vehicle interior material has excellent mechanical strength that can be evaluated by, for example, tearing properties and the like, and excellent recycling properties. The concentration of the ester group contained in the aliphatic polyester resin means the concentration of the ester group derived from the aliphatic polyester resin in the composition containing the thermoplastic polyurethane resin and the aliphatic polyester resin described above. This means that it does not contain an ester group derived from a plastic polyurethane resin.

  In the vehicle interior material according to the present invention, the composition ratio of the above-described thermoplastic polyurethane resin or the thermoplastic polyurethane resin composition containing the thermoplastic polyurethane resin and an additive and the aliphatic polyester resin is calculated in terms of weight. It is preferably 95: 5 to 50:20. If the composition ratio of the aliphatic polyester resin is below the above range, the rate of lowering the molecular weight of the thermoplastic polyurethane resin having an ester bond may be significantly reduced. Moreover, when the blending ratio of the aliphatic polyester resin exceeds the above range, the mechanical properties of a molded product produced using the resin composition may be significantly reduced. Here, examples of mechanical properties include tearing physical properties. That is, if the blending ratio of the aliphatic polyester resin exceeds the above range, the tearing physical properties of the manufactured vehicle interior material may be significantly reduced. The tear property evaluation method is not particularly limited, and examples thereof include a tear test of JISK 6301 (1995).

Other Components The vehicle interior material according to the present invention is not limited to the above-described thermoplastic polyurethane resin having an ester bond and an aliphatic polyester resin, and may contain other components. Here, examples of other components include known and commonly used pigments, inorganic fillers, plasticizers, mold release agents, organic fillers, dispersants, ultraviolet absorbers (light stabilizers), antioxidants, and the like. .

Molding Method The vehicle interior material according to the present invention configured as described above can be manufactured in a desired shape by any conventionally known molding method. Specifically, examples of the molding method include slush molding, extrusion molding, injection molding, blow molding, vacuum molding and compression molding. In particular, the vehicle interior material according to the present invention is preferably manufactured in a desired shape by applying a slush molding method.

  For example, the box containing the resin composition containing the above-described thermoplastic polyurethane resin and aliphatic polyester resin and a heated mold are both vibrated and rotated, and the powder is melted and flowed in the mold, and then cooled and solidified. Thus, the method can be suitably implemented by a method for manufacturing a vehicle interior material. The mold temperature is preferably 200 to 300 ° C, more preferably 210 to 280 ° C.

  According to the slush molding method described above, for example, a vehicle interior material having a thickness of about 0.5 to 1.5 mm can be manufactured. In addition, the obtained vehicle interior material can be set as a resin molded product by setting the surface to be in contact with the foaming mold, pouring urethane foam, and forming a foam layer of 5 mm to 15 mm on the back surface. Here, examples of the vehicle interior material include an instrument panel and a door trim.

  In addition, in order to manufacture the resin composition containing the above-mentioned thermoplastic polyurethane resin and aliphatic polyester resin as a powder composition, the powder material of each composition is mixed using a mixing apparatus. As the mixing device, a known powder mixing device can be used, and any of a container rotation type mixer, a fixed container type mixer and a fluid motion type mixer can be used. For example, as a fixed container type mixer, a high-speed flow type mixer, a double-shaft paddle type mixer, a high-speed shear mixing device (Hensiel mixer (registered trademark), etc.), a low-speed mixing device (planetary mixer, etc.), or a conical screw mixer A dry blending method using a machine (Nauter Mixer (registered trademark) or the like) is well known. Among these methods, it is preferable to use a double-shaft paddle type mixer, a low speed mixing device (such as a planetary mixer), and a conical screw mixer (such as a Nauter mixer (registered trademark)).

  On the other hand, in order to produce the resin composition containing the above-described thermoplastic polyurethane resin and aliphatic polyester resin as pellets, for example, after melting and mixing these resins, the mixed resin is extruded and cut into a desired size. . As the pellet manufacturing apparatus, a granulating apparatus such as a pelletizer can be usually used. According to the pellet manufacturing apparatus, the resin composition melted from the die of the extruder is extruded into a string shape, and is cut into a pellet shape of a desired size with a cutting apparatus.

  The vehicle interior material manufactured as described above can be easily and inexpensively recycled by chemical recycling while having strength according to the application. That is, the above-described molded product can be easily reduced in molecular weight by chemical recycling, and thus can be used as a product excellent in recycling characteristics.

EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, the technical scope of this invention is not limited to a following example.
[Example 1]
In a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, polybutylene adipate (616.2 parts) having a number average molecular weight (hereinafter referred to as Mn) of 1,000, antioxidant (1.2 parts) ) [Ciba Specialty Chemicals Co., Ltd .; IRGANOX1010] Kaolin (90.7 parts) [Georgia Engel Co., Ltd .; ASP400P] having a volume average diameter of 9 μm was charged, purged with nitrogen, and stirred uniformly at 60 ° C. with stirring. . Subsequently, 1-octanol (10.4 parts) and MEK (125.0 parts) were charged, stirred uniformly, cooled to 50 ° C., charged with hexamethylene diisocyanate (155.3 parts), and heated at 90 ° C. for 6 hours. Reacted. Cooled to 60 ° C. and charged with UV absorber (1.9 parts) [manufactured by Ciba Specialty Chemicals; TINUVIN571] and carbodiimide (13.6 parts) [manufactured by Nisshinbo Industries, Inc .; Carbolite V-09M] The mixture was stirred uniformly to obtain a prepolymer solution (UP-1). The NCO content of the obtained prepolymer solution (UP-1) was 2.1%.

  Next, hexamethylenediamine (116 parts), excess methyl ethyl ketone (hereinafter referred to as MEK, 288 parts, 4 times the molar amount with respect to the diamine) and n-hexane (29 parts) were refluxed at 80 ° C. for 24 hours. Product water was removed out of the system. Thereafter, unreacted MEK and n-hexane were removed under reduced pressure to obtain a MEK ketiminate (K-1).

  Next, the prepolymer solution (UP-1) (100.0 parts) obtained above and MEK ketiminate (K-1) (5.4 parts) were mixed and charged into the reaction vessel, and a dispersant ( Sanyo Kasei Kogyo Co., Ltd .; Sunspear PS-8) (24 parts by weight) dissolved in 300 parts by weight of aqueous solution was added. . This mixture was transferred to a reaction vessel equipped with a thermometer, a stirrer, and a nitrogen blowing tube, and deMEK was performed for 2 hours under reduced pressure at 60 ° C. while stirring. Filtration and drying were performed to produce polyurethane resin powder (B-1).

  103.0 parts of the obtained polyurethane resin powder (B-1), phosphate ester plasticizer [manufactured by Daihachi Chemical Co., Ltd .; CR741] 11.5 parts, stabilizer [manufactured by Sanyo Chemical Industries, Ltd .; neomer DA600] 4.0 parts, light stabilizer [Ciba Specialty Chemicals Co., Ltd .; Sanol LS765] 0.3 parts, dimethylpolysiloxane [Toray Dow Corning Co., Ltd .; SH200 (10000)] 0 .1 part, 0.1 part of modified dimethylpolysiloxane [manufactured by Shin-Etsu Chemical Co., Ltd .; X-22-3710ST] was added and mixed at 70 ° C. for 4 hours.

  Next, after cooling to room temperature, 6.3 parts of plant-derived polylactic acid resin fine powder (A2-1) [manufactured by Mitsui Chemicals, Inc .; LACEA H-400 (Mn 20,000, derived from corn)] was mixed. A resin powder composition for molding (S-1) was obtained.

  A thermoplastic polyurethane resin composition comprising a polyurethane resin powder (B-1), a phosphate ester plasticizer, a stabilizer, a light stabilizer, a release agent dimethylpolysiloxane, and a modified dimethylpolysiloxane, and a polylactic acid resin. The composition ratio was 95: 5.

<Method for creating molded sheet>
The resin powder composition for slush molding (S-1) is poured into a Ni electric mold with a grain that has been heated to 250 ° C. in advance, and after 10 seconds, excess colored slush molding material is discharged. After standing at room temperature for 60 seconds and then cooling with water and demolding, a uniform skin (slush molding) having a thickness of about 1 mm was obtained.

[Example 2]
In this example, a slush molded article was produced in the same manner as in Example 1 except that the composition ratio of the thermoplastic polyurethane resin composition having an ester bond and the polylactic acid resin was 90:10.

Example 3
In this example, a slush molded article was produced in the same manner as in Example 1 except that the composition ratio of the thermoplastic polyurethane resin composition having an ester bond and the polylactic acid resin was 80:20.

Example 4
In this example, a slush molded article was produced in the same manner as in Example 1 except that the composition ratio of the thermoplastic polyurethane resin composition having an ester bond and the polylactic acid resin was 70:30.

Example 5
In this example, a slush molded article was produced in the same manner as in Example 1 except that the composition ratio of the thermoplastic polyurethane resin composition having an ester bond and the polylactic acid resin was 50:50.

[Comparative Example 1]
In this comparative example, the composition ratio of the thermoplastic polyurethane resin composition having an ester bond to the polylactic acid resin was 100: 0, that is, the same as in Example 1 without mixing the polylactic acid resin into the thermoplastic polyurethane resin composition. Thus, a slush molded body was produced.

[Evaluation of low molecular weight]
The slush molded articles produced in Examples 1 to 3 and Comparative Example 1 were compared in terms of molecular weight reduction rate in order to evaluate biodegradation characteristics by chemical recycling. Specifically, the slush molded body was treated in a constant temperature and humidity machine at a temperature of 80 ° C. and a humidity of 95% RH for 200 hours. After the test, the tear strength of the epidermis was measured and compared with the initial strength. The tear strength retention after the wet heat aging test was calculated by the following formula.
Tear strength retention rate (%) = (Tear strength after wet heat aging test / Tear strength before wet heat aging test) × 100
The results are shown in Table 1 and FIG.

  From the results shown in Table 1 and FIG. 1, it can be evaluated that the molded article of the thermoplastic polyurethane resin composition having an ester bond alone is unsuitable for chemical recycling because the rate of molecular weight reduction is extremely low. On the other hand, compared with this, in the molded product produced using the composition comprising the thermoplastic polyurethane resin composition having an ester bond and the aliphatic polyester resin, the rate of molecular weight reduction is greatly improved. I understand. From this result, it was found that a molded article produced using a composition comprising a thermoplastic polyurethane resin composition having an ester bond and an aliphatic polyester resin having a carboxylic acid at the terminal is suitable for chemical recycling.

〔Evaluation of the physical properties〕
About the slush molded object produced in Examples 1-5 and the comparative example 1, in order to evaluate the intensity | strength as a molded object, the tearing physical property was evaluated. Specifically, three JISK 6301 (1995) tear test specimen dumbbells No. B were punched from the slush molded body. The plate thickness was the minimum value at five locations in the vicinity of the bent location. This was attached to an autograph, pulled at a speed of 200 mm / min, and the maximum strength at which the test piece broke was calculated.

  The results are shown in FIG. From the results shown in FIG. 2, the tearing properties tend to decrease as the component ratio of the aliphatic polyester resin contained in the resin composition is increased. In particular, it has been found that when the aliphatic polyester resin exceeds 20% by weight, the aliphatic polyester resin is less than 60% compared to the tearing physical properties of a molded article made of a thermoplastic polyurethane resin having an ester bond alone. From this result, it was found that the composition ratio of the thermoplastic polyurethane resin composition and the aliphatic polyester resin is preferably in the range of 95: 5 to 80:20 in terms of weight.

[Ester group concentration]
The ester group concentration derived from the aliphatic polyester resin contained in the resin compositions prepared in Examples 1 to 3 and Comparative Example 1, and the decomposition rate (physical property retention rate (%)) in the molded body produced using the resin composition FIG. 3 shows the relationship with / hour (Hr)). The ester group concentration contained in the thermoplastic polyurethane resin composition was 7.0 mol / kg in all of the resin compositions of Examples 1 to 3 and Comparative Example 1.

  As can be seen from FIG. 3, it can be seen that when the ester group concentration derived from the aliphatic polyester resin exceeds 0.7 mol / kg, the decomposition rate of the molded product is improved. In particular, it can be seen that when the ester group concentration derived from the aliphatic polyester resin exceeds 2 mol / kg, the decomposition rate of the molded product is remarkably improved. From this result, it became clear that the decomposition rate of the molded product can be appropriately adjusted according to the concentration of ester groups derived from the aliphatic polyester resin.

Claims (6)

  A vehicle interior material comprising a thermoplastic polyurethane resin containing an ester group and an aliphatic polyester resin having a carboxylic acid at a terminal.   The composition ratio between the thermoplastic polyurethane resin or the thermoplastic polyurethane resin composition containing the thermoplastic polyurethane resin and an additive and the aliphatic polyester resin is 95: 5 to 80:20 in terms of weight. The vehicle interior material according to claim 1, wherein   2. The vehicle according to claim 1, wherein the concentration of the ester group derived from the aliphatic polyester resin in the composition containing the thermoplastic polyurethane resin and the aliphatic polyester resin is 0.7 to 2.8 mol / kg. Interior material.   2. The vehicle interior material according to claim 1, wherein the aliphatic polyester resin is polyhydroxyalkanoic acid.   2. The vehicle interior material according to claim 1, wherein the aliphatic polyester resin is polylactic acid.   2. The vehicle interior material according to claim 1, wherein the vehicle interior material is molded by slush molding.

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