JP2009155366A - Foam molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foam molded article which has excellent shock absorption properties, particularly to provide a foam molded article which is capable of absorbing considerable energy when receiving a high-speed shock, and which has excellent lightweight properties. <P>SOLUTION: The foam molded article is obtained by foam molding of a thermoplastic resin composition comprising a thermoplastic resin (A) and a resin (B) having a reactive functional group, wherein when, in a tensile test of the thermoplastic resin composition, tensile elastic moduli at tensile velocities V1 and V2 are expressed by E(V1) and E(V2), respectively, E(V1)>E(V2) is satisfied at the time of V1<V2, and foam particles in the foam molded article are present in the thermoplastic resin (A) in a ratio of ≥50% to the entire thermoplastic resin composition. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a foam molded article having excellent impact absorption. More specifically, it is a foam-molded article excellent in light weight that can absorb large energy when subjected to a high-speed impact.

  In recent years, from the viewpoint of pedestrian protection and occupant protection, development of shock absorbing parts has been progressing mainly in automobile interior and exterior applications.

  Typical examples of shock absorbing materials include thermoplastic elastomers such as polyurethane, but their range of use is often limited due to their low heat resistance, and in recent years materials with excellent heat resistance and impact resistance due to polymer alloys Has been developed. Patent Documents 1 and 2 disclose a thermoplastic composition having excellent heat resistance and impact resistance composed of polyamide and ionomer. However, when the material is subjected to a high-speed impact, the maximum load applied to the object is high and the material itself is destroyed. Therefore, a material having a better shock absorption is desired at present.

  Patent Document 3 discloses a resin composition and an impact-absorbing member in which the elastic modulus decreases and becomes flexible as the tensile speed is increased. The composition has been shown to absorb large amounts of energy when subjected to high-velocity impacts, and there is a description that foam molding is possible. However, no specific presentation has been made regarding foam molding, and when general foam molding is performed, there has been a problem in that the amount of energy absorbed when subjected to a high-speed impact is reduced.

Patent Document 4 discloses a method for producing a lightweight molded article using a master batch in which a foaming agent is dispersed in an elastomer (rubber) component. However, in this method, the amount of energy absorbed when subjected to high-speed impact was low.
U.S. Pat. No. 3,845,163 Japanese Patent Laid-Open No. 51-151797 JP 2006-89701 A JP 2002-34897A

  An object of the present invention is to provide a foam molded article that has a high energy absorption amount when subjected to a high-speed impact and is excellent in lightness.

In order to achieve the above object, the present invention has the following configuration. That is, the present invention
(1) A foamed molded article obtained by foaming a thermoplastic resin composition containing a thermoplastic resin (A) and a resin (B) having a reactive functional group, and the thermoplastic resin composition is subjected to a tensile test, A thermoplastic resin composition characterized in that E (V1)> E (V2) when V1 <V2 when the tensile modulus of elasticity at tensile speeds V1 and V2 is E (V1) and E (V2). The ratio of the foamed particles in the foamed molded product in the thermoplastic resin (A) to the entire thermoplastic resin composition is 50% or more,
(2) The foamed article according to (1), wherein the foamed particles have an average cell diameter in the range of 0.1 to 1000 μm,
(3) In the tensile test, when the tensile breaking elongation at the tensile speeds V1 and V2 is ε (V1) and ε (V2) in the tensile test, when V1 <V2, ε (V1) <Ε (V2), (1) or (2) the foam-molded article according to any one of the above,
(4) The thermoplastic resin (A) is at least one selected from polyamide resin, polyester resin, polyphenylene sulfide resin, styrene resin, polyphenylene oxide resin, polycarbonate resin, polylactic acid resin, and polypropylene resin. (1) to (3) The foamed molded product according to any one of the above items,
(5) The foamed molded article according to any one of (1) to (4), wherein the resin serving as a base of the resin (B) having a reactive functional group is a rubber polymer.
(6) The reactive functional group of the resin (B) having the reactive functional group is at least one selected from an amino group, a carboxyl group, a carboxyl metal salt, an epoxy group, an acid anhydride group, and an oxazoline group. The foam molded article according to any one of (1) to (5).

  According to the present invention, in the tensile test, when the tensile elastic moduli at the tensile speeds V1 and V2 are E (V1) and E (V2), when V1 <V2, E (V1)> E (V2) When performing foam molding using a thermoplastic resin composition characterized by having a foam molded product with high energy absorption when subjected to high-speed impact by generating foam particles in a specific region can do.

  The foamed molded article of the present invention is a high impact-resistant thermoplastic resin composition having specific viscoelastic properties described later. The foamed molded article has a foamed particle in the foamed molded article. It is necessary that the proportion of the thermoplastic resin (A) present in the entire composition is 50% or more. On the other hand, in the foam-molded product in which the ratio existing in the thermoplastic resin (A) with respect to the entire thermoplastic resin composition is lower than 50%, the energy absorption amount is significantly reduced when subjected to a high-speed impact.

  In addition, the foam molded product is a ratio in which the foam particles in the foam molded product are present in the thermoplastic resin (A) with respect to the entire thermoplastic resin composition for the purpose of further increasing the amount of energy absorption when subjected to a high-speed impact. Is preferably 60% or more, and more preferably 70% or more.

  In order to adjust the ratio in which the foamed particles in the foamed molded article are present in the thermoplastic resin (A) with respect to the entire thermoplastic resin composition, the foaming agent described later has a high affinity with the thermoplastic resin (A). This can be achieved by using a foaming agent.

  Further, in the present invention, the ratio of the expanded particles in the foamed molded product is distinguished by using an appropriate dye as a dye and by contrasting the thermoplastic resin (A) and the resin (B) having a reactive functional group. Thereafter, from the sum of the cross-sectional areas of the bubbles present in the thermoplastic resin (A) with respect to the sum of the cross-sectional areas of the bubbles that can be observed within 40 mm × 40 mm at the center of the parallel portion of the ISO TYPE-A test piece using a scanning electron microscope. Can be sought.

  In addition, the foamed molded product of the present invention is a high impact-resistant thermoplastic resin composition having specific viscoelastic properties to be described later. In order to sufficiently reflect the high impact resistance, The average cell diameter of the expanded particles is preferably in the range of 0.1 to 1000 μm. In addition, the foam molded article preferably has an average cell diameter of the foamed particles in the foam molded article in the range of 1 to 500 μm for the purpose of further increasing the amount of energy absorbed when subjected to high-speed impact. Is more preferably in the range of 1 to 100 μm.

  In the present invention, the particle diameter of the expanded particles in the expanded molded article is obtained from the number average diameter of the cross-sectional area of the bubble diameter that can be observed within 40 mm × 40 mm in the center of the parallel part of the ISO TYPE-A test piece using a scanning electron microscope. be able to.

  The foamed molded article of the present invention comprises a thermoplastic resin composition containing a thermoplastic resin (A) and a resin (B) having a reactive functional group.

  The thermoplastic resin (A) used in the present invention is not particularly limited as long as it is a resin that can be molded by heating and melting. For example, polyamide resin, polyester resin, polyphenylene sulfide resin, polyphenylene oxide resin, polycarbonate resin, Polylactic acid resin, polyacetal resin, polysulfone resin, tetrafluoroethylene resin, polyetherimide resin, polyamideimide resin, polyimide resin, polyethersulfone resin, polyetherketone resin, polythioetherketone resin, polyetheretherketone resin, polyethylene Preferred examples include at least one thermoplastic resin selected from resins, polypropylene resins, styrene resins such as polystyrene resins and ABS resins, rubbery polymers, polyalkylene oxide resins and the like. Kill.

  Among the thermoplastic resins shown above, polyamide resins, polyester resins, polyphenylene sulfide resins, styrene resins, polyphenylene oxide resins, polycarbonate resins, polylactic acid resins, and polypropylene resins are preferably used. Polyester resins and polyphenylene oxide resins are most preferably used because of their high end group reactivity.

  In the present invention, the polyamide resin is a resin composed of a polymer having an amide bond, and is mainly composed of amino acid, lactam or diamine and dicarboxylic acid. Representative examples of the raw materials include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and paraaminomethylbenzoic acid, lactams such as ε-caprolactam and ω-laurolactam, tetramethylenediamine, penta Methylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, metaxylene Diamine, paraxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis (4 -Aminocyclohex Sil) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminopropyl) piperazine, aminoethylpiperazine, aliphatic, alicyclic, aromatic Diamines, and adipic acid, speric acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid Examples thereof include aliphatic, alicyclic, and aromatic dicarboxylic acids such as acid, hexahydroterephthalic acid, and hexahydroisophthalic acid. In the present invention, polyamide homopolymers or copolymers derived from these raw materials are used individually or individually. It can be used in the form of a mixture.

  Specific examples of particularly useful polyamide resins in the present invention include polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polypentamethylene adipamide (nylon 56), polytetramethylene. Adipamide (nylon 46), polyhexamethylene sebamide (nylon 610), polypentamethylene sebacamide (nylon 510), polyhexamethylene dodecane (nylon 612), polyundecanamide (nylon 11), polydodecane Amide (nylon 12), polycaproamide / polyhexamethylene terephthalamide copolymer (nylon 6 / 6T), polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (nylon 66 / 6T), polyhexamethylene adipamide / Poly Xamethylene isophthalamide copolymer (nylon 66 / 6I), polyhexamethylene adipamide / polyhexamethylene isophthalamide / polycaproamide copolymer (nylon 66 / 6I / 6), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (Nylon 6T / 6I), polyhexamethylene terephthalamide / polydodecanamide copolymer (nylon 6T / 12), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6T / 6I) ), Polyxylylene adipamide (nylon XD6), polyhexamethylene terephthalamide / poly-2-methylpentamethylene terephthalamide copolymer (nylon 6T) M5T), polyhexamethylene terephthalamide / poly pentamethylene terephthalamide copolymer (nylon 6T / 5T), and mixtures thereof or copolymers, and the like.

  Particularly preferable examples include polyamide 6, polyamide 66, polyamide 610, polyamide 11, polyamide 12, polyamide 6/66 copolymer, polyamide 6/12 copolymer and the like. Furthermore, it is also practically preferable to use these polyamide resins as a mixture depending on required properties such as moldability, heat resistance, toughness, and surface properties. Among these, polyamide 6, polyamide 66, polyamide 610, and polyamide 11 are suitable. Polyamide 12 is most preferred.

  The degree of polymerization of these polyamide resins is not particularly limited, and the relative viscosity measured at 25 ° C. in a 98% concentrated sulfuric acid solution having a sample concentration of 0.01 g / ml is preferably in the range of 1.5 to 7.0. A polyamide resin in the range of 1.8 to 6.0 is preferred. When the relative viscosity is less than 1.5, it is difficult to express the excellent shock absorption characteristic of the foam molded article of the present invention. When the relative viscosity is more than 5.0, the thermoplastic resin composition is melted. This is not preferable because the viscosity is remarkably increased and it becomes difficult to form a foam molded product.

  In the present invention, the polyester resin is a thermoplastic resin composed of a polymer having an ester bond in the main chain, and a dicarboxylic acid (or an ester-forming derivative thereof) and a diol (or an ester-forming derivative thereof). And a polymer or a copolymer obtained by a condensation reaction having as a main component thereof, or a mixture thereof.

  Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, and 4,4′-diphenyl ether dicarboxylic acid. Acid, aromatic dicarboxylic acid such as 5-sodiumsulfoisophthalic acid, adipic acid, sebacic acid, azelaic acid, aliphatic dicarboxylic acid such as dodecanedioic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc. And alicyclic dicarboxylic acids and ester-forming derivatives thereof. The diol component is an aliphatic glycol having 2 to 20 carbon atoms, that is, ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, decamethylene glycol. , Cyclohexanedimethanol, cyclohexanediol and the like, or long-chain glycols having a molecular weight of 400 to 6000, that is, polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene glycol and the like, and ester-forming derivatives thereof.

  Preferred examples of these polymers or copolymers include polybutylene terephthalate, polybutylene (terephthalate / isophthalate), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), Polybutylene naphthalate, polyethylene terephthalate, polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / 5-sodium sulfoisophthalate), polybutylene (terephthalate / 5-sodium sulfoisophthalate), polyethylene Naphthalate, polycyclohexanedimethylene terephthalate, etc. Polybutylene terephthalate, polybutylene (terephthalate / adipate), polybutylene (terephthalate / decane dicarboxylate), polybutylene naphthalate, polyethylene terephthalate, polyethylene (terephthalate / adipate), polyethylene naphthalate, polycyclohexanedimethylene terephthalate, etc. Particularly preferred is polybutylene terephthalate (polybutylene terephthalate resin).

  The polybutylene terephthalate resin has an intrinsic viscosity measured in a 0.5% o-chlorophenol solution at 25 ° C. in the range of 0.35 to 2.00, more preferably 0.50 to 1.50. A range is preferred. Moreover, you may use together polybutylene terephthalate resin from which intrinsic viscosity differs, and it is preferable that intrinsic viscosity exists in the range of 0.35-2.00.

  Further, the polybutylene terephthalate resin is durable if the COOH end group amount obtained by potentiometric titration of the m-cresol solution with an alkaline solution is in the range of 1 to 50 eq / t (end group amount per ton of polymer). From the point of anisotropy suppressing effect, it can be preferably used.

  Specific examples of the polyphenylene oxide resin include poly (2,6-dimethyl-1,4-phenylene oxide), poly (2-methyl-6-ethyl-1,4-phenylene oxide), and poly (2,6 -Diphenyl-1,4-phenylene oxide), poly (2-methyl-6-phenyl-1,4-phenylene oxide), poly (2,6-dichloro-1,4-phenylene oxide) and the like. Further, a copolymer such as a copolymer of 2,6-dimethylphenol and other phenols (for example, 2,3,6-trimethylphenol) can be mentioned. Among them, poly (2,6-dimethyl-1,4-phenylene oxide) and a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol are preferable, and in particular, poly (2,6-dimethyl) -1,4-phenylene oxide) is preferred.

  The polyphenylene oxide resin preferably has a reduced viscosity measured in a 0.5 g / dl chloroform solution at 30 ° C. in the range of 0.15 to 0.70.

  The method for producing such a polyphenylene oxide resin is not particularly limited, and those obtained by a known method can be used. For example, it can be easily produced by oxidative polymerization using as a catalyst a complex of cuprous salt and amine by Hay described in US Pat. No. 3,306,874.

  The resin (B) having a reactive functional group used in the present invention is a resin having a reactive functional group in a molecular chain, and is obtained by introducing a reactive functional group into a base resin.

  The resin serving as the base of the resin (B) having a reactive functional group is a thermoplastic resin different from the thermoplastic resin (A) described above, and is not particularly limited, but is preferably a polyamide resin, a polyester resin, or a polyphenylene Sulfide resin, polyphenylene oxide resin, polycarbonate resin, polylactic acid resin, polyacetal resin, polysulfone resin, polytetrafluoroethylene resin, polyetherimide resin, polyamideimide resin, polyimide resin, polyethersulfone resin, polyetherketone resin, polythioether From the above-mentioned thermoplastic resins (A) from ketone resins, polyether ether ketone resins, polyethylene resins, polypropylene resins, styrene resins such as polystyrene resins and ABS resins, rubber polymers, polyalkylene oxide resins, etc. It is possible to use at least one resin selected to differ from the. Among them, the resin used as the base of the resin (B) having a reactive functional group is more preferably a polyethylene resin, a polypropylene resin, a styrene resin, or a rubbery polymer because of the ease of introduction of the reactive functional group, and further shock absorption. From the viewpoint of imparting properties, a rubbery polymer is more preferable.

  In the present invention, the rubbery polymer generally contains a polymer having a glass transition temperature lower than room temperature, and some of the intermolecular molecules are constrained by covalent bonds, ionic bonds, van der Waals forces, entanglement, etc. It is a polymer. Examples of rubber polymers include polybutadiene, polyisoprene, styrene-butadiene random copolymers and block copolymers, hydrogenated products of the block copolymers, acrylonitrile-butadiene copolymers, butadiene-isoprene copolymers, and the like. Diene rubber, ethylene-propylene random copolymer and block copolymer, ethylene-butene random copolymer and block copolymer, ethylene and α-olefin copolymer, ethylene-acrylic acid, ethylene -Ethylene-unsaturated carboxylic acid copolymer such as methacrylic acid, ethylene-acrylic acid ester, ethylene-unsaturated carboxylic acid ester copolymer such as ethylene-methacrylic acid ester, part of unsaturated carboxylic acid is a metal salt A certain ethylene-acrylic acid-acrylic acid metal salt Acrylic elasticity such as ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer such as ethylene-methacrylic acid-methacrylic acid metal salt, acrylic ester-butadiene copolymer such as butyl acrylate-butadiene copolymer Polymers, copolymers of ethylene and fatty acid vinyl such as ethylene-vinyl acetate, ethylene-propylene non-conjugated diene terpolymers such as ethylene-propylene-ethylidene norbornene copolymer, ethylene-propylene-hexadiene copolymer Preferred examples include thermoplastic elastomers such as butylene-isoprene copolymer, chlorinated polyethylene, polyamide elastomer, and polyester elastomer.

  When a polyamide resin is used as the thermoplastic resin (A), among these, from the viewpoint of compatibility, ethylene-unsaturated carboxylic acid ester copolymer, ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer Coalescence is preferably used.

  The unsaturated carboxylic acid ester in the ethylene-unsaturated carboxylic acid ester copolymer is a (meth) acrylic acid ester, preferably an ester of (meth) acrylic acid and an alcohol. Specific examples of unsaturated carboxylic acid esters include (meth) acrylic acid such as methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylate-2-ethylhexyl, stearyl (meth) acrylate Examples include esters.

  The weight ratio of the ethylene component to the unsaturated carboxylic acid ester component in the copolymer is not particularly limited, but is preferably in the range of 90/10 to 10/90, more preferably 85/15 to 15/85.

  The number average molecular weight of the ethylene-unsaturated carboxylic acid ester copolymer is not particularly limited, but is preferably in the range of 1000 to 70000 from the viewpoint of fluidity and mechanical properties.

  Specific examples of the unsaturated carboxylic acid in the ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer include (meth) acrylic acid. Examples of unsaturated carboxylic acid metal salts include (meth) acrylic acid metal salts. Although the metal of unsaturated carboxylic acid metal salt is not specifically limited, Preferably, alkali metals, such as sodium, alkaline-earth metals, such as magnesium, zinc etc. are mentioned.

  The weight ratio of the unsaturated carboxylic acid component to the unsaturated carboxylic acid metal salt component in the ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer is not particularly limited, but preferably 95/5 to 5/95, More preferably, it is the range of 90/10-10/90.

  The number average molecular weight of the ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer is not particularly limited, but is preferably in the range of 1000 to 70000 from the viewpoint of fluidity and mechanical properties.

  The reactive functional group contained in the resin (B) having a reactive functional group is not particularly limited as long as it reacts with the functional group present in the thermoplastic resin (A), preferably an amino group, Examples thereof include at least one selected from a carboxyl group, a carboxyl metal salt, a hydroxyl group, an acid anhydride group, an epoxy group, an isocyanate group, a mercapto group, an oxazoline group, and a sulfonic acid group. Of these, amino groups, carboxyl groups, carboxyl metal salts, epoxy groups, acid anhydride groups, and oxazoline groups are more preferred because they are highly reactive and have few side reactions such as decomposition and crosslinking.

  When the acid anhydride group is introduced into the rubbery polymer, the method can be carried out by a generally known technique and is not particularly limited. For example, maleic anhydride, itaconic anhydride, endic acid anhydride, A method of copolymerizing acid anhydrides such as citraconic anhydride and 1-butene-3,4-dicarboxylic acid anhydride and a monomer that is a raw material of the rubber polymer, grafting the acid anhydride onto the rubber polymer Or the like can be used.

  In addition, when the epoxy group is introduced into the rubbery polymer, the method can be carried out by a generally known technique and is not particularly limited. For example, glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, itacon A method of copolymerizing a vinyl monomer having an epoxy group, such as a glycidyl ester compound of an α, β-unsaturated acid such as glycidyl acid, with a monomer which is a raw material of a rubbery polymer, having the above functional group A method of polymerizing a rubbery polymer using a polymerization initiator or a chain transfer agent, a method of grafting an epoxy compound onto a rubbery polymer, or the like can be used.

  Further, when the oxazoline group is introduced into the rubbery polymer, the method can be carried out by a generally known technique and is not particularly limited. For example, 2-isopropenyl-oxazoline, 2-vinyl-oxazoline, 2 A method of copolymerizing a vinyl monomer having an oxazoline group such as -acryloyl-oxazoline or 2-styryl-oxazoline with a monomer which is a raw material of a rubbery polymer can be used.

  The number of functional groups per molecular chain in the resin (B) having a reactive functional group is not particularly limited, but usually 1 to 10 is preferable, and 1 to 5 in order to reduce side reactions such as crosslinking. Preferably. Moreover, although the molecule | numerator which does not have a functional group at all may be contained, it is so preferable that the ratio is small.

  Although there is no restriction | limiting in particular about the compounding ratio of the thermoplastic resin (A) and the resin (B) which has a reactive functional group in the foaming molded article of this invention, The weight Aw of a thermoplastic resin (A) and a reactive functional group The ratio Aw / Bw of the resin (B) having a weight Bw is preferably in the range of 5/95 to 95/5, more preferably in the range of 10/90 to 90/10, and 15/85 to 85/15. A range is most preferred. When Aw / Bw is lower than 5/95, the reaction between the resins (B) having reactive functional groups becomes remarkable, and there is a tendency that molding processing becomes difficult due to an increase in viscosity, and Aw / Bw is 95/5. If the ratio exceeds 1, the amount of the functional group that reacts with the thermoplastic resin (A) decreases, and the effect of improving the mechanical properties of the thermoplastic resin composition and the manifestation effect of unique viscoelastic behavior tend to be small, which is not preferable. .

  Further, the thermoplastic resin composition used for the foamed molded article of the present invention has a tensile elastic modulus of E (V1) and E (V2) at a tensile speed of V1 and V2 in a tensile test, where V1 <V2. , E (V1)> E (V2). The above relational expression is preferably established for all V1 and V2 within the range of the tensile speed of 10 mm / min to 500 mm / min, and more preferably any V1 within the range of 1 mm / min to 1000 mm / min. , V2 is preferably established.

  Further, when the tensile elongation at break is ε (V1) and ε (V2) at the tensile speeds V1 and V2, it is preferable that ε (V1) <ε (V2) when V1 <V2. The tensile elongation at break indicates the elongation at the moment of fracture. The above relational expression is preferably established for all V1 and V2 within the range of the tensile speed of 10 mm / min to 500 mm / min, and more preferably any V1 within the range of 1 mm / min to 1000 mm / min. , V2 is preferably established.

  As a method for producing the thermoplastic resin composition used in the foamed molded article of the present invention, production in a molten state or production in a solution state can be used. From the viewpoint of improving reactivity, production in a molten state is possible. It can be preferably used. For production in a molten state, melt kneading with an extruder, melt kneading with a kneader, or the like can be used. From the viewpoint of productivity, melt kneading with an extruder that can be continuously produced can be preferably used. For melt kneading by an extruder, one or more extruders such as a single screw extruder, a twin screw extruder, a multi screw extruder such as a four screw extruder, and a twin screw single screw compound extruder can be used. From the viewpoint of improvement in productivity, reactivity, and productivity, a multi-screw extruder such as a twin-screw extruder or a four-screw extruder can be preferably used, and a method by melt kneading using a twin-screw extruder is most preferable.

  When producing a thermoplastic resin composition used for a foamed molded article in the present invention, when using a twin screw extruder, there is no particular limitation, but from the viewpoint of improving kneadability and reactivity, the value of L / D0 is It is preferably 50 or more, more preferably 60 to 200, and even more preferably 80 to 200. Even when a twin screw extruder having an L / D0 of less than 50 is used, the L / D0 through which the thermoplastic resin composition passes is preferably 50 or more by kneading a plurality of times. The L / D0 is a value obtained by dividing the screw length L by the screw diameter D. The screw length is the length from the upstream end of the screw segment at the position (feed port) where the screw base material is supplied to the screw tip. Here, the raw material refers to the present invention such as thermoplastic resin (A), resin (B) having a reactive functional group, fillers added as other components, thermoplastic resins, rubbers, various additives, and the like. All the components necessary for obtaining the thermoplastic resin composition are shown. The screw of the twin screw extruder is configured by combining screw segments having different lengths and shape characteristics such as full flight and kneading disc. In the extruder, the side to which raw materials are supplied may be referred to as upstream, and the side from which molten resin is discharged may be referred to as downstream.

  When an extruder having a sampling valve or the like is used for sampling from the middle of the extruder, the screw length L is “upstream of the screw segment at the position (feed port) where the raw material of the screw is supplied. It can be considered that it is the same as that kneaded by a normal extruder equal to the “length from the end portion to the sampling location” and having a screw diameter D0 equal to the screw diameter of an extruder having a sampling valve or the like. The sampling location here refers to a position on the screw shaft on the upstream side closest to the port through which the resin in the cylinder is discharged.

  In addition, when using a twin screw extruder when producing a thermoplastic resin composition for use in a foam molded product, it is possible to improve the kneadability and reactivity. And a kneading zone. The full flight zone is composed of one or more full flights, and the kneading zone is composed of one or more kneading discs.

  When producing a thermoplastic resin composition in the present invention, when a twin screw extruder is used, the resin in the kneading zone that is the maximum of the resin pressures indicated by the resin pressure gauges installed in the kneading zones at a plurality of locations. When the pressure is Pkmax (MPa), and the resin pressure in the minimum full flight zone among the resin pressures indicated by the resin pressure gauges installed in a plurality of full flight zones is Pfmin (MPa), the value of Pkmax is ( It is preferable to produce the thermoplastic resin composition used for the foamed molded article of the present invention under conditions of Pfmin + 0.3) or more, more preferably conditions of (Pfmin + 0.4) or more, and conditions of (Pfmin + 0.5) or more. More preferably, it is manufactured. A kneading zone composed of one or more kneading discs is more excellent in kneadability and reactivity of the molten resin than a full flight zone composed of one or more full flights. By filling the kneading zone with the molten resin, the kneading property and the reactivity are drastically improved. As an index indicating the state of filling of the molten resin, there is a value of the resin pressure, and the larger the resin pressure, the more standard the molten resin is filled. That is, in the production of the thermoplastic resin composition used in the foamed molded article of the present invention, when using a twin screw extruder, by increasing the resin pressure in the kneading zone within a certain range from the resin pressure in the full flight zone. It is possible to effectively promote the reaction, and in the tensile test, when the tensile elastic modulus is E (V1) and E (V2) at the tensile speeds V1 and V2, when V1 <V2, A feature satisfying (V1)> E (V2) can be remarkably expressed.

  There are no particular restrictions on how to increase the resin pressure in the kneading zone, but there is an effect of accumulating the reverse screw zone and the molten resin between the kneading zones and downstream of the kneading zone, which has the effect of pushing the molten resin upstream. For example, a method of introducing a seal ring zone having a gap can be preferably used. The reverse screw zone and the seal ring zone are composed of one or more reverse screws and one or more seal rings, which can be combined.

  For example, when a reverse screw zone is introduced between kneading zones or downstream of the kneading zone, assuming that the length of each reverse screw zone is Lr, all the reverse screw zones have Lr / D0 = 0.1. It is preferable from a viewpoint of kneading | mixing property and reactivity to have length of -10. The length Lr / D0 of each reverse screw zone is more preferably 0.2 to 8, and further preferably 0.3 to 6. The length Lr of the reverse screw zone is defined as a perpendicular line from the upstream end portion of the most upstream reverse screw constituting the reverse screw zone to the screw shaft center line, and from the downstream end portion of the most downstream reverse screw to the screw shaft center. The distance between the perpendicular to the line.

  Moreover, when manufacturing the thermoplastic resin composition used for the foamed molded article of the present invention, when a twin-screw extruder is used, the extrusion amount of the thermoplastic resin composition is 0.01 kg / h or more per 1 rpm of the screw. It is preferably 0.05 kg / h to 1 kg / h, more preferably 0.08 to 0.5 kg / h, and most preferably 0.1 to 0.3 kg / h. The extrusion amount is an extrusion rate of the thermoplastic resin composition discharged from the extruder, and is a weight (kg) extruded per hour.

  In addition, the preferable numerical range regarding the extrusion amount in the said twin-screw extruder is based on the extrusion amount of a twin-screw extruder with a screw diameter of 37 mm. When the screw diameters are significantly different, for example when using a twin screw extruder with a diameter of less than 30 mm or more than 50 mm, the extrusion rate is preferably 2. It can be read as an increase / decrease according to the fifth power law or the third power law, more preferably according to the 2.5 power law.

  For example, when a twin screw extruder having a screw diameter of 20 mm is used, assuming that the extrusion amount conforms to the 2.5th power rule of the screw diameter ratio before and after the scale down, the extrusion amount of the thermoplastic resin composition is the number of screw rotations. Preferably, 0.002 kg / h or more per 1 rpm, more preferably 0.01 to 0.2 kg / h, still more preferably 0.017 to 0.11 kg / h, most preferably 0.02 to 0.06 kg / h. h.

  Further, when a twin screw extruder having a screw diameter of 100 mm is used, assuming that the extrusion amount conforms to the 2.5th power rule of the screw diameter ratio before and after the scale-up, the extrusion amount of the thermoplastic resin composition is per 1 rpm of the screw. It is preferably 0.12 kg / h or more, more preferably 0.6 to 12 kg / h, still more preferably 0.96 to 6 kg / h, and most preferably 1.2 to 3.6 kg / h.

  Moreover, there is no restriction | limiting in particular as a rotational speed of a screw, Usually, 10 rpm or more, Preferably it is 15 rpm or more, More preferably, it is 20 rpm or more. The extrusion rate is not particularly limited, but is usually 0.1 kg / h or more, preferably 0.15 kg / h or more, and more preferably 0.2 kg / h or more.

  Moreover, when manufacturing the thermoplastic resin composition used for the foam molded article of the present invention, when using a twin screw extruder, the residence time in the twin screw extruder of the thermoplastic resin composition is 1 to 30 minutes. It is preferable that it is 1.5 to 28 minutes, more preferably 2 to 25 minutes. The residence time is an average of the residence time from when the raw material is supplied to the twin screw extruder until it is discharged, and is a steady melt kneading in which the uncolored thermoplastic resin composition is adjusted to a predetermined extrusion amount. In the state, from the position of the screw base to which the raw material is supplied, together with the raw material, usually about 1 g of the colorant is added, and from the time when the colorant is added, the thermoplastic resin composition is extruded from the discharge port of the extruder, The time until the point at which the degree of coloring by the colorant on the extrudate is maximized is taken.

  In addition, when producing a thermoplastic resin composition for use in the foamed molded product of the present invention, when using a twin screw extruder, the screw of the twin screw extruder is not particularly limited, and is a complete mesh type, incomplete mesh type. A screw such as a mold or a non-engagement type can be used, but a complete engagement type screw is preferred from the viewpoints of kneadability and reactivity. Further, the direction of rotation of the screw may be either the same direction or a different direction, but from the viewpoint of kneadability and reactivity, the same direction is preferable. When a twin screw extruder is used in the present invention, the screw is most preferably a co-rotating fully meshing type.

  In addition, when a twin screw extruder is used in the present invention, the screw configuration of the twin screw extruder is a combination of full flight and / or kneading disks, which is effective for a molten thermoplastic resin composition. A screw configuration that imparts a shear field to is preferred. Therefore, as described above, it is preferable that the screw of the twin-screw extruder has a plurality of kneading zones composed of one or more kneading disks in the longitudinal direction, and the total of these kneading zones The length is preferably in the range of 5 to 50%, more preferably 10 to 40%, and still more preferably 15 to 30% of the total length of the screw.

  Further, when the twin screw extruder is used in the present invention, assuming that the length of each kneading zone in the screw of the twin screw extruder is Lk, all kneading zones have Lk / D0 = 0.2-10. It is preferable from the viewpoints of kneading property and reactivity. The length Lk / D0 of each kneading zone is more preferably 0.3 to 9, and further preferably 0.5 to 8. The length Lk of the kneading zone is determined by the perpendicular line from the upstream end of the most upstream kneading disk constituting the kneading zone to the screw shaft center line and the screw from the downstream end of the most downstream kneading disk. The distance between the vertical line to the axis center line.

  Moreover, when using a twin-screw extruder by this invention, it is preferable that the kneading zone of a twin-screw extruder is arrange | positioned over the whole region, without uneven distribution in the specific position in a screw.

  When a twin-screw extruder is used in the present invention, it is preferable to introduce an inert gas from the raw material charging part and melt knead to suppress thermal deterioration. Nitrogen gas is preferred as the inert gas.

  In the thermoplastic resin composition used for the foamed molded article of the present invention, other components other than the above (A) and (B) may be added as necessary within the range not impairing the characteristics. Examples of other components include fillers, thermoplastic resins, rubbers, and various additives.

  For example, a filler may be used as necessary to improve strength, dimensional stability, and the like. The filler may be fibrous or non-fibrous, or a combination of fibrous filler and non-fibrous filler may be used.

  Examples of the filler include glass fiber, glass milled fiber, carbon fiber, potassium titanate whisker, zinc oxide whisker, aluminum borate whisker, aramid fiber, alumina fiber, silicon carbide fiber, ceramic fiber, asbestos fiber, stone-kow fiber, metal Fibrous fillers such as fibers, wollastonite, zeolite, sericite, kaolin, mica, clay, pyrophyllite, bentonite, asbestos, talc, alumina silicate and other silicates, alumina, silicon oxide, magnesium oxide, zirconium oxide, Metal compounds such as titanium oxide and iron oxide, carbonates such as calcium carbonate, magnesium carbonate and dolomite, sulfates such as calcium sulfate and barium sulfate, hydroxides such as magnesium hydroxide, calcium hydroxide and aluminum hydroxide, Rasubizu, ceramic beads, non-fibrous fillers such as boron nitride and silicon carbide and the like, which may be hollow, it is also possible to further combination of these fillers 2 or more. In addition, these fibrous and / or non-fibrous fillers are pretreated with a coupling agent such as an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, an epoxy compound, This is preferable in terms of obtaining superior mechanical properties.

  In order to improve strength, dimensional stability and the like, when such a filler is used, the amount of the filler is not particularly limited, but it is preferably 30 to 400 parts by weight based on 100 parts by weight of the thermoplastic resin composition.

  Moreover, in the thermoplastic resin composition used for the foam-molded article of the present invention, other thermoplastic resins can be blended as necessary within the range not impairing the characteristics.

  Examples of such thermoplastic resins include polyamide resins, polyester resins, polyphenylene sulfide resins, polyphenylene oxide resins, polycarbonate resins, polylactic acid resins, polyacetal resins, polysulfone resins, tetrafluoropolyethylene resins, polyetherimide resins, polyamideimides. Resin, polyimide resin, polyethersulfone resin, polyetherketone resin, polythioetherketone resin, polyetheretherketone resin, polyethylene resin, polypropylene resin, styrene resin such as polystyrene resin and ABS resin, polyalkylene oxide resin, etc. It is done. Two or more of these thermoplastic resins can be used in combination. When such thermoplastic resins are used, the blending amount thereof is not particularly limited, but is preferably blended by 1 to 400 parts by weight with respect to 100 parts by weight of the thermoplastic resin composition.

  Furthermore, in the thermoplastic resin composition used for the foamed molded article of the present invention, other rubbers and various additives can be blended as necessary within the range not impairing the characteristics.

  Such rubbers include, for example, polybutadiene, polyisoprene, styrene-butadiene random copolymers and block copolymers, hydrogenated block copolymers, acrylonitrile-butadiene copolymers, butadiene-isoprene copolymers, and the like. Diene rubber, ethylene-propylene random copolymer and block copolymer, ethylene-butene random copolymer and block copolymer, ethylene and α-olefin copolymer, ethylene-acrylic acid, ethylene -Ethylene-unsaturated carboxylic acid copolymer such as methacrylic acid, ethylene-acrylic acid ester, ethylene-unsaturated carboxylic acid ester copolymer such as ethylene-methacrylic acid ester, part of unsaturated carboxylic acid is a metal salt A ethylene-acrylic acid-acrylic acid metal , Ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer such as ethylene-methacrylic acid-methacrylic acid metal salt, acrylic ester-butadiene copolymer such as butyl acrylate-butadiene copolymer Ethylene-propylene non-conjugated diene terpolymers such as elastic polymers, ethylene-fatty acid vinyl copolymers such as ethylene-vinyl acetate, ethylene-propylene-ethylidene norbornene copolymers, ethylene-propylene-hexadiene copolymers Preferred examples thereof include thermoplastic elastomers such as coalescence, butylene-isoprene copolymer, chlorinated polyethylene, polyamide elastomer, and polyester elastomer, and modified products thereof. Two or more kinds of such rubbers can be used in combination. When such rubbers are used, the blending amount thereof is not particularly limited, but is preferably blended by 1 to 400 parts by weight with respect to 100 parts by weight of the thermoplastic resin composition.

  The various additives that can be added to the thermoplastic resin composition used in the foamed molded article of the present invention are preferably crystal nucleating agents, anti-coloring agents, hindered phenols, hindered amines and other antioxidants, ethylene bis Examples include mold release agents such as stearyl amide and higher fatty acid esters, plasticizers, heat stabilizers, lubricants, UV inhibitors, colorants, flame retardants, and the like.

  These rubbers and various additives can be blended at any stage for producing the thermoplastic resin composition of the present invention. For example, the thermoplastic resin composition of the present invention can be blended with a twin screw extruder. When manufacturing, the method of adding at the time of compounding the resin, the method of adding the resin by a method such as side feed during melt kneading, the method of adding the resin after melt kneading in advance, and the thermoplastic A method of adding the remaining resin to one resin constituting the resin composition, melt-kneading, and the like is mentioned.

  When the thermoplastic resin composition in the foam molded article of the present invention is produced by a twin screw extruder, a supercritical fluid can also be introduced from the viewpoint of improving the reactivity when melt kneading with the twin screw extruder. . Such a supercritical fluid is a fluid that exceeds the limit point (critical point) at which gas and liquid can coexist, and has both gas properties (diffusibility) and liquid properties (solubility). is there. Such supercritical fluids include supercritical carbon dioxide, supercritical nitrogen, supercritical water, etc., preferably supercritical carbon dioxide and supercritical nitrogen can be used, most preferably supercritical carbon dioxide can be used. .

  The foam molding product of the present invention can be molded by any foam molding method. For example, when the thermoplastic resin composition is melt-kneaded, a foaming agent that foams the thermoplastic resin (A) is added, and after melt-kneading, a molding method or a foaming agent that foams the thermoplastic resin (A), Examples of the method include dry blending with the thermoplastic resin composition of the present invention before molding.

  Further, as such a foaming agent, it is necessary to appropriately select a foaming agent having a high affinity with the thermoplastic resin (A). As the types of foaming agents, azodicarbonamide, dinitrosopentamethylenetetramine, azobisisobutyro Nitriles, sodium bicarbonate and the like are mentioned as preferred examples, and these foaming agents can be appropriately mixed and used. Moreover, the masterbatch goods which mix | blended the diluent dispersant with the foaming agent can also be used.

  The addition amount of the foaming agent is 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the thermoplastic resin (A) as a pure foaming agent. Furthermore, as a bubble regulator, inorganic powder such as talc and silica, acidic salt of polyvalent carboxylic acid, reaction mixture of polyvalent carboxylic acid and sodium carbonate or sodium bicarbonate, etc. may be added, The amount is preferably 13 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin (A).

  The foamed molded product of the present invention thus obtained is a foamed molded product having a high energy absorption when subjected to a high-speed impact.

  The foamed molded product of the present invention is preferably used as a moving device member, a portable device member, and a building member. Particularly preferably, it is used as an automobile part. Examples of mobile equipment include vehicles, ships, and bicycles, and portable equipment members include computer-related parts, VTR parts, TV parts, compact discs, DVD and other audio / video equipment parts, and mobile phone parts. , Cameras, watches, etc., and building materials include, for example, civil engineering building walls, roofs, ceiling material related parts, window material related parts, insulation related parts, flooring related parts, seismic isolation / vibration control related parts Parts, lifeline related parts, shutters, guardrails, chairs, etc. Although it is not particularly limited as an automobile part, for example, bumper, fender, garnish, door panel, roof panel, front grill, lamp housing, spoiler, grill apron cover frame, door handle, door molding, rear finisher, wheel cover, wheel cap, pillar, Examples include side members, safety belt parts, instrument panels, airbag peripheral parts, door pads, console boxes, hood panels, trunk lids, door mirror stays, and hood louvers.

  Hereinafter, the effects of the present invention will be described more specifically with reference to examples. In addition, this invention is not limited to the following Example.

The thermoplastic resin (A) used in this example and the comparative example is as follows.
(A-1): Nylon 6 resin having a relative viscosity of 2.75 at a melting point of 225 ° C. and 0.01 g / ml in 98% sulfuric acid.

Similarly, the resin (B) having a reactive functional group is as follows.
(B-1): Glycidyl methacrylate-modified polyethylene copolymer (hereinafter abbreviated as GMA-modified PE copolymer) “Bond First BF-7L” (manufactured by Sumitomo Chemical Co., Ltd.)

Similarly, resins other than (A) and (B) are as follows.
(C-1): Unmodified polyethylene copolymer (hereinafter abbreviated as unmodified PE copolymer) “LOTRYL29MA03” (manufactured by Arkema)
(D-1): Thermoplastic polyurethane “Elastolan NY97A”
(BASF)
(E-1): Foaming agent for engineering plastics “Fine blow V10N” (manufactured by Nitto Kako)
(E-2): Foaming agent for polyolefin “Fine blow S10N” (manufactured by Nitto Chemical Industries)

(1) Production of dumbbell test piece Using Nissei Plastic Industries injection molding machine (NP7-1F), molding temperature 260 ° C. (220 ° C. in Comparative Example 3), mold temperature 80 ° C. (Comparative Example 3 20 ° C.) ), A JIS-5A dumbbell-type test piece (length 75 mm × end width 12.5 mm × thickness 2 mm) was produced under the conditions of injection pressure lower limit pressure + 5 kgf / cm 2.

(2) Evaluation of tensile elastic modulus and tensile elongation at break of dumbbell specimens JIS-5A dumbbell specimens obtained by injection molding were subjected to Autograph AG100kNG (manufactured by Shimadzu Corporation), and the distance between chucks was set to 50 mm. Tensile tests were conducted at speeds of 100 mm / min, 500 mm / min, and 1000 mm / min, and the tensile modulus and tensile elongation at break at each speed were evaluated. Note that the tensile elongation at break was the elongation at break based on a distance between chucks of 50 mm.

(3) Production of Foam Molded Article Using a Nissei Plastic Industries injection molding machine (NP7-1F), a molding temperature of 260 ° C. (220 ° C. in Comparative Example 3) and a mold temperature of 80 ° C. (Comparative Example 3 of 20 ° C.) ), A flat molded article of 130 mm × 130 mm × thickness 10 mm and an ISO TYPE-A test piece were prepared under the condition of injection pressure lower limit pressure + 5 kgf / cm 2.

(4) Analysis of Foamed Particles of Foamed Molded Product The ratio of the foamed particles in the foamed molded product is determined by ISO TYPE- using a scanning electron microscope after dyeing the thermoplastic resin (A) with ruthenium tetroxide as a dyeing agent. It calculated | required from the sum total of the cross-sectional area of the bubble which exists in the thermoplastic resin (A) with respect to the sum total of the cross-sectional area of the bubble which can be observed within 40 mm x 40 mm of A test piece parallel part center.

  The foamed particle diameter in the foamed molded product was determined from the number average diameter of the cross-sectional area of the bubble diameter that can be observed within 40 mm × 40 mm at the center of the parallel part of the ISO TYPE-A test piece using a scanning electron microscope.

(5) Impact resistance evaluation of foam-molded product Impact in accordance with JIS-Z0235 when a weight of 2 cm weight is dropped from a height of 2.5 m to a foam-molded product with a bottom area of 70 cm2 and a weight of 2 kg. The value was measured.

Examples 1 and 2 and Comparative Example 1
Nylon 6 resin (A-1) is used as the thermoplastic resin (A) and GMA-modified PE copolymer (B-1) is used as the resin (B) having a reactive functional group. While mixing and performing nitrogen flow, the screw diameter is 37 mm and the screw is a double screw L / D0 = 100, in the same direction rotating fully meshing twin screw extruder (Toshiba Machine Co., Ltd., TEM-37BS- 26/2 V) was used, melt kneading was performed at a cylinder temperature of 260 ° C., a screw rotation number and an extrusion amount shown in Table 1, and a strand-like molten resin was discharged from a discharge port (L / D = 100). At that time, the coloring agent was added together with the raw materials, and the time during which the coloring of the extrudate was maximized was measured as the residence time. The residence time is shown in Table 1. Further, as the screw configuration: A, seven kneading zones starting from the positions of L / D0 = 2, 28, 43, 55, 69, 77, 93 are provided, and the length Lk / D0 of each kneading zone is In order, Lk / D0 = 1.8, 1.8, 2.3, 2.3, 2.3, 2.3, and 3.0. Further, a reverse screw zone is provided on the downstream side of each kneading zone, and the length Lr / D0 of each reverse screw zone is Lr / D0 = 0.4, 0.4, 0.8, 0.8, 0.4, 0.8, and 0.4. Further, when the ratio (%) of the total length of the kneading zone to the total length of the screw is calculated by (total length of kneading zone) / (total length of screw) × 100, the ratio of the total length of the kneading zone is 16%. Resin pressure gauges installed in multiple full flight zones from the resin pressure Pkmax (MPa) of the maximum kneading zone among the resin pressures indicated by the resin pressure gauges installed in multiple kneading zones Table 1 shows values obtained by subtracting the resin pressure Pfmin (MPa) of the full flight zone that is minimized among the resin pressures indicated by. The vent vacuum zone was provided at a position of L / D0 = 96, and volatile components were removed at a gauge pressure of −0.1 MPa. The discharged strand-shaped molten resin was cooled by passing through a cooling bath and cut while being taken out by a pelletizer, thereby obtaining a pellet-shaped sample of the thermoplastic resin composition. The sample was vacuum-dried at 80 ° C. for 12 hours or more, and then the above-described injection molding was carried out to evaluate the tensile elastic modulus and tensile breaking elongation of the dumbbell test piece.

  Further, a foamed product was obtained by dry blending a foaming agent with a blending amount shown in the lower part of Table 1 and foam-molding the pellet-shaped sample of the thermoplastic resin composition, and impact resistance was evaluated. Table 1 shows the analysis results of the foamed particles of the foam molded product and the impact resistance evaluation results.

Comparative Example 2
Except for using the unmodified PE copolymer (C-1) instead of the resin (B) having a reactive functional group, melt kneading was carried out in the same manner as in Example 1 to obtain a thermoplastic resin composition. It was. The sample was vacuum-dried at 80 ° C. for 12 hours or more, and then the above-described injection molding was carried out to evaluate the tensile elastic modulus and tensile breaking elongation of the dumbbell test piece.

  Further, a foamed molded product was obtained by dry blending a foaming agent with a blending amount shown in the lower part of Table 1 and foam molding the pellet-shaped sample of the thermoplastic resin composition. Table 1 shows the analysis results of the foamed particles of the foam molded product and the impact resistance evaluation results.

Comparative Example 3
The thermoplastic polyurethane (D-1), which is a typical shock absorbing material, was subjected to the above-described injection molding, and the tensile modulus and tensile breaking elongation of the dumbbell specimen were evaluated.

  Moreover, with respect to the said thermoplastic polyurethane (D-1), the foaming agent was dry-blended with the compounding quantity shown to the lower stage of Table 1, and the foaming molding product was obtained by foam-molding. Table 1 shows the analysis results of the foamed particles of the foam molded product and the impact resistance evaluation results.

  From Examples 1 and 2, using the thermoplastic resin composition of the present invention, the ratio of the foamed particles in the foamed molded product in the thermoplastic resin (A) to the entire thermoplastic resin composition is 50% or more. Thus, it can be seen that the amount of energy absorbed when subjected to a high-speed impact is high (the impact value received from the foamed molded product is as low as 5 G or less), and is excellent for use in impact absorbing members.

  On the other hand, even when the same thermoplastic resin composition as in Examples 1 and 2 was used, the proportion of the thermoplastic resin (A) present in the entire thermoplastic resin composition was lower than 50% as in Comparative Example 1. In this case, the amount of energy absorbed when subjected to a high-speed impact was low (the impact value received from the foamed molded product was as high as 30 G).

  When the unmodified PE copolymer (C-1) is used instead of the resin (B) having a reactive functional group shown in Comparative Example 2, the thermoplastic resin (A) in the entire thermoplastic resin composition Even if the ratio present in the water is 50% or more, the amount of energy absorbed when subjected to high-speed impact is low (the impact value received from the foamed molded product is as high as 33G).

  Further, the thermoplastic polyurethane, which is a representative impact absorbing material shown in Comparative Example 3, has a low energy absorption amount when subjected to a high-speed impact after foam molding (the impact value received from the foam molded product is as high as 25 G). )

  From these results, the thermoplastic resin composition containing the thermoplastic resin (A) and the resin (B) having a reactive functional group is made into a foamed molded product formed by foaming, and such a thermoplastic resin composition is used in a tensile test. A thermoplastic resin composition characterized in that E (V1)> E (V2) when V1 <V2 when the tensile elastic modulus is E (V1) and E (V2) at the tensile speeds V1 and V2. When the ratio of the foamed particles in the foamed molded product in the thermoplastic resin (A) to the thermoplastic resin composition as a whole is 50% or more, a high-speed impact was applied. It can be seen that it is possible to obtain for the first time a foamed molded article having a large energy absorption amount.

Claims (6)

This is a foamed molded article obtained by foaming a thermoplastic resin composition containing a thermoplastic resin (A) and a resin (B) having a reactive functional group, and this thermoplastic resin composition has a tensile speed V1 in a tensile test. , V2 is a thermoplastic resin composition characterized in that E (V1)> E (V2) when V1 <V2, where E (V1) and E (V2) are tensile elastic moduli. The foamed molded product is characterized in that the ratio of the foamed particles in the thermoplastic resin (A) to the entire thermoplastic resin composition is 50% or more. The foamed article according to claim 1, wherein the foamed particles have an average cell diameter in the range of 0.1 to 1000 µm. In the tensile test, when the tensile breaking elongation at the tensile speeds V1 and V2 is ε (V1) and ε (V2), the thermoplastic resin composition has ε (V1) <ε (V1 <V2). The foamed molded product according to claim 1, wherein the foamed molded product is V2). The thermoplastic resin (A) is at least one selected from polyamide resin, polyester resin, polyphenylene sulfide resin, styrene resin, polyphenylene oxide resin, polycarbonate resin, polylactic acid resin, and polypropylene resin. Item 1. The foam molded article according to any one of Items 1 to 3. The foamed molded article according to any one of claims 1 to 4, wherein the resin serving as a base of the resin (B) having a reactive functional group is a rubbery polymer. The reactive functional group of the resin (B) having the reactive functional group is at least one selected from an amino group, a carboxyl group, a carboxyl metal salt, an epoxy group, an acid anhydride group, and an oxazoline group. The foam molded article according to any one of claims 1 to 5.