JP6825856B2 - Resin composition - Google Patents

Description

The present invention relates to a resin composition containing a polyamide resin and a polyester resin.

Polyamide resin has excellent mechanical properties, chemical resistance, and durability in its molded body, so various parts in the fields of automobiles, electrical / electronic fields, mechanical / industrial fields, office equipment fields, aerospace fields, etc. It is widely used as a material for. In addition, polyester resin is also used as an engineering plastic in various industrial fields because its molded product has excellent mechanical properties and chemical resistance. However, the molded product made of polyamide resin has a large dimensional change and physical property change due to water absorption, and the molded product made of polyester resin has a drawback that the crystallization rate is slow and the moldability is poor. Therefore, a resin composition containing a polyamide resin and a polyester resin has been proposed for the purpose of compensating for these drawbacks and further utilizing the excellent properties of the polyamide resin and the polyester resin. However, the polyamide resin and the polyester resin have low compatibility, and a molded product made of a resin composition containing these resins has a problem of being inferior in mechanical strength.

Therefore, as a resin composition capable of improving the compatibility between the polyamide resin and the polyester resin and obtaining a molded product having excellent mechanical strength, Japanese Patent Application Laid-Open No. 5-214244 (Patent Document 1) describes the polyamide resin 10 to 10. 0.1 to 10 parts of a vinyl copolymer composed of a vinyl monomer such as styrene or methyl methacrylate and a glycidyl ester group-containing vinyl monomer in 100 parts by mass of a mixture of 90% by mass and 90 to 10% by mass of a thermoplastic polyester resin. A resin composition containing parts by mass is disclosed. However, the molded product made of this resin composition has a problem that it is inferior in flexural modulus and bending strength.

Japanese Unexamined Patent Publication No. 5-214244

The present invention has been made in view of the above-mentioned problems of the prior art, and in a molded product made of a resin composition containing a polyamide resin and a polyester resin, the flexural modulus can be increased without significantly reducing the bending strength. It is an object of the present invention to provide a resin composition which can be improved.

As a result of diligent research to achieve the above object, the present inventors have added a vinyl alcohol-based polymer in a specific ratio to a resin composition containing a polyamide resin and a polyester resin to obtain a molded product thereof. Found that the flexural modulus was improved without significantly reducing the bending strength, and completed the present invention.

That is, the resin composition of the present invention is measured by dynamic viscoelasticity measurement with a polyamide resin having a glass transition temperature of 50 ° C. or higher determined from the peak of the loss tangent-temperature curve measured by dynamic viscoelasticity measurement. It contains a polyester resin having a glass transition temperature of 50 ° C. or higher and polyvinyl alcohol , which are obtained from the peak of the loss tangent-temperature curve.
The total content of the polyamide resin and the polyester resin is 99.9 to 85.0 parts by mass, the content of the polyvinyl alcohol is 0.1 to 15.0 parts by mass, and the polyamide resin and the polyester It is characterized in that the mass ratio with the resin (polyamide resin: polyester resin) is 1: 9 to 9: 1.

Although it is not always clear why the molded product made of the resin composition of the present invention improves the flexural modulus without significantly reducing the bending strength, the present inventors presume as follows. That is, in the resin composition of the present invention, the hydroxyl group in the vinyl alcohol-based polymer acts as a catalyst for the transesterification reaction between the polyamide resin and the polyester resin, and this transesterification reaction produces a polyamide-polyester copolymer. Then it is inferred. Then, since this polyamide-polyester copolymer acts as a compatibilizer between the polyamide resin and the polyester resin, the interfacial strength between the polyamide resin and the polyester resin is improved, so that the mixed state of these resins is changed. It is presumed that it will improve. Further, the hydroxyl group in the vinyl alcohol-based polymer also forms a strong hydrogen bond with the carbonyl group of the polyamide resin and the polyester resin, so that the adhesive strength between the polyamide resin and the polyester resin is improved, and thus the mixed state of these resins. Is presumed to improve. As described above, in the resin composition of the present invention, it is presumed that the coexistence of the vinyl alcohol-based polymer improves the mixed state of the polyamide resin and the polyester resin, so that the flexural modulus of the molded product is improved.

According to the present invention, in a molded product made of a resin composition containing a polyamide resin and a polyester resin, it is possible to improve the flexural modulus without significantly reducing the bending strength.

Hereinafter, the present invention will be described in detail according to its preferred embodiment.

The resin composition of the present invention comprises a polyamide resin having a glass transition temperature (hereinafter, simply referred to as “glass transition temperature”) determined from the peak of the loss tangent-temperature curve measured by dynamic viscoelasticity measurement and 50 ° C. or higher. Contains a polyester resin having a glass transition temperature (hereinafter, simply referred to as "glass transition temperature") determined from the peak of the loss tangent-temperature curve measured by dynamic viscoelasticity measurement of 50 ° C. or higher, and a vinyl alcohol-based polymer. It is something to do.

(Polyamide resin)
The polyamide resin used in the present invention is a polymer having a chain skeleton formed by polymerizing a plurality of monomers via an amide bond (-NH-CO-), and has a glass transition temperature. There is no particular limitation as long as the temperature is 50 ° C. or higher. By using a polyamide resin having a glass transition temperature of 50 ° C. or higher, a molded product having high mechanical strength can be obtained even in a temperature atmosphere exceeding room temperature. The upper limit of the glass transition temperature of the polyamide resin is not particularly limited, but is usually 150 ° C. or lower.

Examples of the monomer constituting such a polyamide resin include amino acids such as aminocaproic acid and paraaminomethylbenzoic acid; and lactams such as ε-caprolactam. These monomers may be used alone or in combination of two or more.

Further, in the present invention, a copolymer of diamine and dicarboxylic acid can also be used as the polyamide resin. Examples of the diamine include ethylene diamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, and 1,9-diaminononane. 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,13-diaminotridecane, 1,14-diaminotetradecane, 1,15-diaminopentadecane, 1,16-diaminohexadecane, 1,17-diaminoheptadecane, 1,18-diaminooctadecane, 1,19-diaminononadecan, 1,20-diaminoeikosan, 2-methyl-1,5-diaminopentane, 2-methyl-1,8- Aliphatic diamines such as diaminooctane; alicyclic diamines such as cyclohexanediamine and bis- (4-aminocyclohexyl) methane; aromatic diamines such as xylylene diamine, p-phenylenediamine and m-phenylenediamine can be mentioned. These diamines may be used alone or in combination of two or more.

Examples of the dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelli acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brushphosphoric acid, and tetradecanedioic acid. Examples thereof include aliphatic dicarboxylic acids such as pentadecanedioic acid and octadecanedioic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid. These dicarboxylic acids may be used alone or in combination of two or more.

Specifically, as such a polyamide resin, polyamide 6 (PA6), polyamide 66 (PA66), polyamide 610 (PA610), polyamide 612 (PA612), polyamide 6T (PA6T), polyamide 6I (PA6I), polyamide 9T ( PA9T), Polyamide M5T (PAM5T), Polyamide 1010 (PA1010), Polyamide 1012 (PA1012), Polyamide 10T (PA10T), Polyamide MXD6 (PAMXD6), Polyamide 6T / 6 (PA6T / 6), Polyamide 6T / 66 (PA6T / 66), Polyamide 6T / 6I (PA6T / 6I), Polyamide 6T / 6I / 66 (PA6T / 6I / 66), Polyamide 6T / 2M-5T (PA6T / 2M-5T), Polyamide 9T / 2M-8T (PA9T / 2M-8T) and the like. These polyamide resins may be used alone or in combination of two or more.

Among such polyamide resins, PA6, PA66, PA610, and PAMXD6 are preferable, and PA6 is more preferable, from the viewpoint of obtaining a molded product having excellent moldability and mechanical strength.

PA6 is a polyamide resin obtained by homopolymerizing ε-caprolactam among the monomers having 6 carbon atoms, and PA66 is a polyamide resin obtained by copolymerizing hexamethylenediamine and adipic acid. PA610 is a polyamide resin obtained by copolymerizing sebacic acid derived from castor oil, which is a vegetable oil, and hexamethylenediamine derived from petroleum. Further, PAMXD6 is a crystalline polyamide resin obtained from m-xylylenediamine (MXDA) and adipic acid.

The method for producing such a polyamide resin is not particularly limited, and a known method can be appropriately adopted. Further, in the present invention, a commercially available polyamide resin may be used. Commercially available polyamide resins include polyamide 6 manufactured by Unitica (trade name: Unitica nylon 6 "A1030BRL"), polyamide 6 manufactured by Ube Industries (trade name: UBE nylon "1015B"), and polyamide 6 manufactured by Toray (trade name: UBE nylon "1015B"). Product name: Alamin (registered trademark) "CM1017"), Polyamide 66 manufactured by Toray (trade name: Alamin (registered trademark) "CM3001-N"), Polyamide MXD6 manufactured by Mitsubishi Gas Chemicals (trade name: Lenny (registered)) Trademark) "S6001") and the like can be mentioned.

(Polyester resin)
The polyester resin used in the present invention is a polymer having a chain skeleton formed by polymerizing a plurality of monomers via an ester bond (-CO-O-), and has a glass transition temperature. There is no particular limitation as long as the temperature is 50 ° C. or higher. By using a polyester resin having a glass transition temperature of 50 ° C. or higher, a molded product having high mechanical strength can be obtained even in a temperature atmosphere exceeding room temperature. The upper limit of the glass transition temperature of the polyester resin is not particularly limited, but is usually 150 ° C. or lower.

Examples of the monomer constituting such a polyester resin include hydroxybenzoic acid, hydroxynaphthoeic acid, and diphenyleneoxycarboxylic acid. These monomers may be used alone or in combination of two or more.

Further, in the present invention, a polycondensate product of a dicarboxylic acid and a diol can also be used as the polyester resin. Examples of the dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelli acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brushphosphoric acid, and tetradecanedioic acid. Examples thereof include aliphatic dicarboxylic acids such as pentadecanedioic acid and octadecanedioic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid. These dicarboxylic acids may be used alone or in combination of two or more.

Examples of the diol include aliphatic diols such as ethylene glycol, propylene glycol, 1,3-propanediol, butanediol, neopentyl glycol, butenediol, pentanediol, and hexanediol; and fats such as cyclohexanediol and cyclohexanedimethanol. Cyclic diols; examples include aromatic diols such as hydroquinone, resorcin, dihydroxyphenyl, naphthalene diol, dihydroxyphenyl ether, and 2,2-bis (4-hydroxyphenyl) propane. These diols may be used alone or in combination of two or more.

Specifically, such polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene succinate (PES), polybutylene succinate (PBS), polylactic acid (PL), and polyhydroxyalkanoic acid (PET). PHA), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT) and the like. These polyester resins may be used alone or in combination of two or more.

Among such polyester resins, PET, PTT, PBT, and PEN are preferable, and PET is more preferable, from the viewpoints of moldability, heat resistance, and mechanical properties.

The PET is a polyester resin obtained by dehydration condensation of ethylene glycol and terephthalic acid, and is inexpensive, has a high melting point, and has excellent mechanical properties. Further, the PTT is a polyester resin obtained by dehydration condensation of dimethyl terephthalate or terephthalic acid and 1,3-propanediol. The PBT is a polyester resin obtained by dehydration condensation of terephthalic acid and 1,4-butanediol. The PEN is a polyester resin obtained by dehydration condensation of 2,6-naphthalenedicarboxylic acid and ethylene glycol.

The method for producing such a polyester resin is not particularly limited, and a known method can be appropriately adopted. Further, in the present invention, a commercially available polyester resin may be used. Commercially available polyester resins include Teijin's polyethylene terephthalate (trade name: TR8550FF), Toray's polybutylene terephthalate (trade name: Trecon (registered trademark) "1401X06"), and Teijin's polyethylene naphthalate (commodity). Name: Teijin® (registered trademark) "TN8050SC") and the like.

(Vinyl alcohol polymer)
The vinyl alcohol-based polymer used in the present invention is a polymer mainly containing a vinyl alcohol monomer unit. In such a vinyl alcohol-based polymer, the ratio of the vinyl alcohol monomer unit is preferably 50 mol% or more, more preferably 70 mol% or more, and further preferably 90 mol% or more of all the monomer units. It is preferably 95 mol% or more, and particularly preferably 95 mol% or more. When the ratio of the vinyl alcohol monomer unit is less than the above lower limit, the bending strength of the molded product tends to be significantly reduced.

Examples of such a vinyl alcohol-based polymer include a saponified product of polyvinyl acetate (a saponified product of a homopolymer of vinyl acetate, for example, polyvinyl alcohol), an ethylene-vinyl alcohol copolymer, and an ethylene-vinyl acetate. Examples thereof include a saponified product of a copolymer (a saponified product of a copolymer of ethylene and vinyl acetate).

In the saponified product of polyvinyl acetate, the degree of saponification of the vinyl acetate monomer unit is preferably 50% or more, more preferably 70% or more, further preferably 90% or more, and particularly preferably 95% or more. When the degree of saponification of the vinyl acetate monomer unit is less than the above lower limit, the proportion of the vinyl alcohol monomer unit is reduced, and the bending strength of the molded product tends to be significantly reduced.

Further, in the ethylene-vinyl alcohol copolymer, the copolymerization ratio of the vinyl alcohol monomer is preferably 50 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 95 mol% or more. When the copolymerization ratio of the vinyl alcohol monomer is less than the above lower limit, the bending strength of the molded product tends to be significantly reduced.

Further, in the saponified product of the ethylene-vinyl acetate copolymer, the copolymerization ratio of the vinyl acetate monomer is 50 mol% or more (more preferably 70 mol% or more, further preferably 90 mol% or more, particularly preferably 95 mol% or more). The degree of saponification of the vinyl acetate monomer unit is preferably 50% or more (more preferably 70% or more, further preferably 90% or more, particularly preferably 95% or more). When the copolymerization ratio of the vinyl acetate monomer or the saponification degree of the vinyl acetate monomer unit is less than the above lower limit, the ratio of the vinyl alcohol monomer unit decreases, and the bending strength of the molded product tends to be significantly reduced.

Among such vinyl alcohol-based polymers, polyvinyl alcohol (usually, the degree of saponification is 98% or more) is most preferable from the viewpoint of improving the flexural modulus without lowering the bending strength of the molded product.

Further, the method for producing such a vinyl alcohol-based polymer is not particularly limited, and a known method can be appropriately adopted. Further, in the present invention, a commercially available vinyl alcohol polymer may be used. Commercially available vinyl alcohol-based polymers include polyvinyl alcohol manufactured by Nippon Synthetic Chemical Industry Co., Ltd. (trade name: Gosenol "N-300") and ethylene-vinyl alcohol copolymer manufactured by Nippon Synthetic Chemical Industry Co., Ltd. (trade name: Soanol). "D2908") and the like.

<Resin composition>
The resin composition of the present invention contains such a polyamide resin, a polyester resin, and a vinyl alcohol-based polymer, and the total content of the polyamide resin and the polyester resin is 99.9 to 85 parts by mass. Is. When the total content of the polyamide resin and the polyester resin is less than the lower limit, the bending strength of the molded product is greatly reduced, while when the total content exceeds the upper limit, the flexural modulus of the molded product is lowered. Further, from the viewpoint of improving the flexural modulus without significantly reducing the bending strength of the molded product, the total content of the polyamide resin and the polyester resin is preferably 99.5 to 90 parts by mass.

Further, in the resin composition of the present invention, the content of the vinyl alcohol-based polymer is 0.1 to 15.0 parts by mass. When the content of the vinyl alcohol polymer is less than the lower limit, the flexural modulus of the molded product is lowered, while when the content exceeds the upper limit, the bending strength of the molded product is greatly lowered. Further, the content of the vinyl alcohol-based polymer is preferably 0.5 to 10 parts by mass from the viewpoint of improving the flexural modulus without significantly reducing the bending strength of the molded product.

Further, in the resin composition of the present invention, the mass ratio of the polyamide resin to the polyester resin (polyamide resin: polyester resin) is 1: 9 to 9: 1. If the mass ratio of the polyamide resin to the polyester resin is less than the lower limit, the moldability of the polyester resin is not improved, while if it exceeds the upper limit, the water absorption of the polyamide resin is not improved. Further, from the viewpoint that the polyamide resin and the polyester resin mutually compensate for the defects by alloying, the mass ratio of the polyamide resin and the polyester resin is preferably 7: 3 to 3: 7.

The method for producing the resin composition of the present invention is not particularly limited, and a known method can be appropriately adopted. For example, the resin composition of the present invention can be obtained by mixing (kneading) the polyamide resin, the polyester resin, and the vinyl alcohol polymer at a predetermined ratio (mixing step). Further, the polyamide resin, the polyester resin and the vinyl alcohol polymer may be mixed in a solution using a soluble solvent.

The mixing method in the mixing step is not particularly limited, and for example, a kneading device such as an extruder (single-screw extruder, twin-screw kneading extruder, etc.), kneader and mixer (high-speed flow mixer, baddle mixer, ribbon mixer, etc.) Can be mixed using. These devices may be used alone or in combination of two or more. Further, when two or more kinds of devices are used in combination, they may be operated continuously or batchwise (in a batch system). Further, before mixing by a kneading device such as an extruder or the like, the polyamide resin, the polyester resin and the vinyl alcohol polymer are mixed at a specific ratio by a dry blend or the like, and then the extruder or the like is used. It may be mixed by the kneading device of.

The mixing temperature in such a mixing step is not particularly limited as long as it is a temperature at which melt mixing can be performed. Since the mixing temperature is appropriately adjusted depending on the type of polyamide resin, the type of polyester resin, and the type of vinyl alcohol polymer, it cannot be said unconditionally, but from the viewpoint of melt mixing, 230 to 230 to The temperature is preferably 330 ° C., more preferably 240 to 300 ° C., and even more preferably 250 to 270 ° C.

In the resin composition of the present invention, it is important to adjust the contents of the polyamide resin, the polyester resin, and the vinyl alcohol polymer to a specific ratio. When the resin composition of the present invention is produced, it is substantially desired by setting the amount of the polyamide resin, the polyester resin and the vinyl alcohol polymer to be charged to be the same as the desired content in the resin composition. A resin composition having a content can be obtained.

The resin composition of the present invention may contain components other than the polyamide resin, the polyester resin and the vinyl alcohol polymer as long as the object of the present invention is not impaired. Such other components include thermoplastic resins other than the above, flame retardants, flame retardants, colorants, antioxidants, fillers, strengthening agents, anti-ultraviolet agents, heat stabilizers, antibacterial agents. , Antistatic agent, etc. can be blended. These other components may be used alone or in combination of two or more. When these other components are contained in the resin composition, the content thereof is preferably 70% by mass or less with respect to the total amount of the resin composition.

Examples of the other thermoplastic resin include polyphenylene oxide-based resin, ABS-based resin, polyolefin-based resin, polycarbonate resin, polyphenylene sulfide resin, and the like. These thermoplastic resins may be used alone or in combination of two or more.

Examples of the flame retardant include halogen-based flame retardants (halogenated aromatic compounds), phosphorus-based flame retardants (nitrogen-containing phosphate compounds, phosphate esters, etc.), nitrogen-based flame retardants (guanidine, triazine, melamine, and the like. These derivatives, etc.), inorganic flame retardants (metal hydroxides, etc.), boron-based flame retardants, silicone-based flame retardants, sulfur-based flame retardants, red phosphorus-based flame retardants, and the like. These flame retardants may be used alone or in combination of two or more.

Examples of the flame retardant aid include various antimony compounds, metal compounds containing zinc, metal compounds containing bismuth, magnesium hydroxide, clay silicate and the like. These flame retardant aids may be used alone or in combination of two or more.

Examples of the colorant include pigments and dyes.

Examples of the filler include glass components (glass fibers, glass beads, glass flakes, etc.), silica, inorganic fibers (glass fibers, alumina fibers, carbon fibers), graphite, silicate compounds (calcium silicate, aluminum silicate, kaolin, etc.). Tark, clay, etc.), metal oxides (iron oxide, titanium oxide, zinc oxide, antimony oxide, alumina, etc.), carbonates and sulfates of metals such as calcium, magnesium, zinc, organic fibers (aromatic polyester fiber, fragrance, etc.) Group polyamide fibers, fluororesin fibers, polyimide fibers, vegetable fibers, etc.) can be mentioned. These fillers may be used alone or in combination of two or more.

Examples of the reinforcing agent include glass fiber, carbon fiber, carbon nanotube (single layer and multilayer), silicon carbide whisker, alumina fiber, BN fiber, aramid fiber, titania fiber, zirconia fiber, and Si-Ti-CO fiber. , Gold-based fiber, silver-based fiber, iron-based fiber, copper-based fiber, vapor phase carbon fiber (VGCF), boron fiber, poly (paraphenylene benzobisoxazole) (PBO) fiber and other reinforcing fibers. These fortifiers may be used alone or in combination of two or more. Further, among these reinforcing agents, glass fiber, carbon fiber, alumina fiber, BN fiber, aramid fiber, and PBO fiber are preferable, and glass fiber and carbon fiber are more preferable, from the viewpoint of improving mechanical properties.

Such a resin composition of the present invention can be molded into a desired shape and used for various purposes. The method for molding the resin composition of the present invention into a desired shape is not particularly limited, and a known molding method can be appropriately adopted. Specifically, injection molding, extrusion molding, transfer molding, vacuum molding, blow molding, foam molding, stretch molding, press molding, extrusion composite molding, injection compression molding, decorative molding, gas assisted injection molding, foam injection molding, Molding methods such as low-pressure molding, ultra-thin wall injection molding (ultra-high-speed injection molding), and in-mold composite molding (insert molding, outsert molding) can be mentioned.

The molded product made of the resin composition of the present invention has an improved flexural modulus without significantly reducing the bending strength, and can be used for various purposes. For example, it can be suitably used in the fields of automobiles, electrical / electronic fields, mechanical / industrial fields, office equipment fields, and aerospace fields. Specifically, it is used as an exterior material, interior material, structural material, etc. of automobiles, railroad vehicles, ships, airplanes, and the like. Among these, examples of automobile supplies include automobile exterior materials, automobile interior materials, automobile structural materials, engine room interior parts, and the like. In addition, interior materials such as buildings and furniture, exterior materials, structural materials and the like can be mentioned. That is, door surface materials, door structural materials, surface materials for various furniture (desks, chairs, shelves, chests of drawers, etc.), structural materials, and the like can be mentioned. Further, it can be used as a housing and a structure of home appliances (thin TV, refrigerator, washing machine, vacuum cleaner, mobile phone, portable game machine, notebook computer, etc.).

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to the following Examples. The resin glass transition temperature was measured by the following method.

<Glass transition temperature>
After molding the resin into a film with a thickness of 500 μm, using a dynamic viscoelasticity measuring device (manufactured by IT Measurement Control Co., Ltd.), the measurement temperature range is -100 to 200 ° C., and the temperature rise rate is 10 ° C./min. Dynamic viscoelasticity measurement was performed under the condition of a frequency of 10 Hz, and the glass transition temperature was obtained from the peak in the obtained loss tangent (tan δ) -temperature curve.

(Example 1)
Polyamide 6 (PA6) (“A1030BRL” manufactured by Unitika Co., Ltd., glass transition temperature: 73 ° C.) 49.75 parts by mass and polyethylene terephthalate (PET) (“TR8550FF” manufactured by Teijin Limited, glass transition temperature: 93 ° C.) ) 49.75 parts by mass and 0.5 parts by mass of polyvinyl alcohol (PVOH) (“Gosenol N-300” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., saponification degree: 98.0-99.0%) After mixing by blending, the mixture was melt-kneaded at 270 ° C. for 5 minutes using a kneading / extrusion evaluation test device (“Laboplast Mill” manufactured by Toyo Seiki Seisakusho Co., Ltd.). The obtained kneaded product was press-molded into a flat plate of 100 mm × 100 mm × 2 mm under the conditions of a temperature of 270 ° C. and a pressure of 6 MPa using a press molding machine, and then cut into a width of 20 mm to prepare a test piece.

(Example 2)
A test piece was prepared in the same manner as in Example 1 except that the compounding amount of PA6 was changed to 45 parts by mass, the compounding amount of PET was changed to 45 parts by mass, and the compounding amount of PVOH was changed to 10 parts by mass.

(Example 3)
Same as in Example 2 except that 10 parts by mass of ethylene-vinyl alcohol copolymer (EVOH) (“Soanol D2908” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., ethylene content: 29 mol%) was used instead of PVOH. A test piece was prepared.

(Comparative Example 1)
A test piece was prepared in the same manner as in Example 1 except that the blending amount of PA6 was changed to 50 parts by mass and the blending amount of PET was changed to 50 parts by mass, and PVOH was not blended.

(Comparative Example 2)
Example 2 and Example 2 except that 10 parts by mass of ethylene-glycidyl methacrylate copolymer (E-GMA) (“Bond First E” manufactured by Sumitomo Chemical Co., Ltd., glycidyl methacrylate content: 12% by mass) was used instead of PVOH. A test piece was prepared in the same manner.

(Comparative Example 3)
A test piece was prepared in the same manner as in Example 1 except that the compounding amount of PA6 was changed to 40 parts by mass, the compounding amount of PET was changed to 40 parts by mass, and the compounding amount of PVOH was changed to 20 parts by mass.

(Comparative Example 4)
A test piece was prepared in the same manner as in Example 1 except that the compounding amount of PA6 was changed to 25 parts by mass, the compounding amount of PET was changed to 25 parts by mass, and the compounding amount of PVOH was changed to 50 parts by mass.

(Comparative Example 5)
A test piece was prepared in the same manner as in Example 1 except that the compounding amount of PA6 was changed to 15 parts by mass, the compounding amount of PET was changed to 15 parts by mass, and the compounding amount of PVOH was changed to 70 parts by mass.

<Bending test>
After vacuum-drying the obtained test piece at 80 ° C. for 12 hours, a three-point bending test is performed using the test piece in an absolutely dry state in accordance with the method specified by JIS K7171, and the flexural modulus and bending strength are obtained. Was measured. These results are shown in Table 1 together with the blending amount of each component.

As is clear from the results shown in Table 1, the resin composition of the present invention in which a vinyl alcohol-based polymer is blended in a resin composition containing a polyamide resin and a polyester resin at a ratio of 0.1 to 15.0% by mass. It was found that the products (Examples 1 to 3) improved the bending elasticity without significantly lowering the bending strength as compared with the resin composition (Comparative Example 1) containing no vinyl alcohol polymer. Further, the resin composition containing polyvinyl alcohol as the vinyl alcohol-based polymer (Example 2) has improved bending strength as compared with the resin composition containing an ethylene-vinyl alcohol copolymer (Example 3). I understand.

On the other hand, the resin composition containing an ethylene-glycidyl methacrylate copolymer instead of the vinyl alcohol-based polymer (Comparative Example 2) is different from the resin composition not containing the vinyl alcohol-based polymer (Comparative Example 1). It was found that the bending elasticity and bending strength were greatly reduced. Further, the resin composition (Comparative Examples 3 to 5) in which the vinyl alcohol-based polymer is blended in a proportion exceeding 15.0% by mass is compared with the resin composition (Comparative Example 1) containing no vinyl alcohol-based polymer. It was found that although the flexural modulus was improved, the bending strength was significantly reduced.

As described above, according to the present invention, in a molded product made of a resin composition containing a polyamide resin and a polyester resin, it is possible to improve the flexural modulus without significantly reducing the bending strength. ..

Therefore, the resin composition of the present invention is used for applications that are required to have both good bending strength and flexural modulus, for example, exterior materials for automobiles, interior materials, structural materials, parts in engine rooms, and the like. It is useful as a raw material.

Claims (1)

Polyamide resin with a glass transition temperature of 50 ° C or higher determined from the peak of the loss tangent-temperature curve measured by dynamic viscoelasticity measurement,
A polyester resin with a glass transition temperature of 50 ° C or higher determined from the peak of the loss tangent-temperature curve measured by dynamic viscoelasticity measurement,
Contains polyvinyl alcohol ,
The total content of the polyamide resin and the polyester resin is 99.9 to 85.0 parts by mass.
The content of the polyvinyl alcohol is 0.1 to 15.0 parts by mass.
A resin composition characterized in that the mass ratio of the polyamide resin to the polyester resin (polyamide resin: polyester resin) is 1: 9 to 9: 1.