Polyurethane resin composition suitable for extrusion molding

Abstract

A polyurethane resin composition including 20-99 parts by mass of a thermoplastic polyurethane elastomer (A) and 1-80 parts by mass of multi-layered structure polymer particles (B), the polyurethane resin composition characterized in that the multi-layered structure polymer particles (B) satisfy the following conditions (1)-(6): (1) the multi-layered structure polymer particles (B) comprise two or more layers, having at least one rubber component layer (I) on the inside thereof and having at least one thermoplastic resin component layer (II) on the outermost side thereof; (2) the rubber component layer (I) is a polymer layer formed through copolymerization of a monomer mixture (i) comprising 50-99.99 mass% of acrylic acid ester, 49.99-0 mass% of another monofunctional monomer that is copolymerizable with the acrylic acid ester, and 0.01-10 mass% of a polyfunctional monomer; (3) the thermoplastic resin component layer (II) is a polymer layer formed through polymerization of a monomer (ii) comprising 40-100 mass% of methacrylic acid ester and 60-0 mass% of another monomer that is copolymerizable with the methacrylic acid ester; (4) the number average molecular weight of the outermost layer polymer of the thermoplastic resin component layer (II) is 30,000 or less, using GPC; (5) the total mass ratio [(I) / (II)] of the rubber component layer (I) to the thermoplastic resin component layer (II) is 30 / 70-90 / 10; (6) the average particle size of the multi-layered structure polymer particles (B) is 150 nm or less; and the melt viscosity ratio ηr of the melt viscosity η(A) of the thermoplastic polyurethane elastomer (A) at a shear velocity of 121.6 sec-1 to the melt viscosity η of the polyurethane resin composition at a shear velocity of 121.6 sec-1 satisfies the following relationships.　Melt viscosity ratio ηr (180°C) at 180°C: η(A) / η>1.0 Melt viscosity ratio ηr (200°C) at 200°C: η(A) / η≤1.0

Description

[Technical Field]

[0001] The present invention relates to a polyurethane resin composition with excellent extrusion moldability, comprising a thermoplastic polyurethane elastomer and multilayer polymer particles. [Background technology]

[0002] Thermoplastic polyurethane elastomers are widely used due to their excellent mechanical, thermal, and electrical properties. Their applications are not limited to injection molding; they are also used in extrusion molding applications such as sheet and film extrusion.

[0003] When thermoplastic polyurethane elastomers are subjected to extrusion molding, such as sheet extrusion molding, the melt viscosity fluctuates significantly with temperature changes within the processing temperature range, making the resin prone to sagging and deformation immediately after exiting the extruder. Furthermore, during film formation, the melt tension is low and highly temperature-dependent, resulting in a narrow range of selectable conditions for film formation, poor film formation stability, and difficulty in thin film formation. These issues stem from the fact that at high temperatures, the thermal decomposition of urethane bonds leads to extremely low viscosity, while at low temperatures, the formation of physical crosslinking points results in low melt fluidity. Thus, obtaining satisfactory molded products from thermoplastic polyurethane elastomers requires processing within a very narrow temperature range.

[0004] Patent Document 1 discloses a polyurethane resin composition for improving the extrusion processability of thermoplastic polyurethane elastomers, comprising a thermoplastic polyurethane elastomer and an acid-containing thermoplastic olefin copolymer with an acid value of 2 to 100. Patent Document 2 discloses a polyurethane resin composition obtained by dynamically crosslinking a composition consisting of a specific ethylene-(meth)acrylic acid copolymer and a specific ethylene-(meth)acrylic acid ester-carbon monoxide copolymer in the presence of a peroxide, in addition to a thermoplastic polyurethane elastomer. Polyurethane resin compositions containing ethylene-(meth)acrylic acid copolymers sometimes impair the mechanical strength and flexibility that are characteristic of thermoplastic polyurethane elastomers. Patent Document 3 discloses a polyurethane resin composition comprising a specific ether-based thermoplastic polyurethane elastomer and a lubricant, but the lubricant bleeds out onto the molded product surface over time, causing stickiness and staining, so it has not been widely used.

[0005] A resin composition comprising a thermoplastic polyurethane elastomer and multilayer polymer particles is known as a polyurethane-based resin composition that exhibits excellent affinity with thermoplastic polyurethane elastomers without substantially impairing the excellent mechanical properties and flexibility of thermoplastic polyurethane elastomers, and does not cause problems such as bleed-out or phase separation. Patent Document 4 discloses a flexible resin composition comprising a thermoplastic polyurethane elastomer and an acrylic-based flexible multilayer polymer. Furthermore, Patent Document 5 discloses a thermoplastic elastomer composition comprising a thermoplastic elastomer and multilayer polymer particles, wherein the multilayer polymer particles consist of two or more layers: a rubber component layer and a thermoplastic resin component layer, and the composition of the rubber component layer, the composition of the thermoplastic resin component layer, the number-average molecular weight (Mn) of the polymer in the outermost thermoplastic resin component layer, and the average particle size of the multilayer polymer particles are optimized. In the examples, a thermoplastic polyurethane elastomer is described as the thermoplastic elastomer. Polyurethane-based resin compositions containing multilayer polymer particles have not yet achieved improved extrusion processability, and currently, satisfactory improved products have not yet been obtained. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 61-271351 [Patent Document 2] Japanese Patent Publication No. 2004-231744 [Patent Document 3] Japanese Patent Application Publication No. 8-27376 [Patent Document 4] Japanese Patent Publication No. 2004-238590 [Patent Document 5] Japanese Patent Publication No. 2005-255872 [Overview of the project] [Problems that the invention aims to solve]

[0007] The object of the present invention is to provide a formulation that reduces the fluctuation of melt viscosity with respect to temperature changes in the processing temperature range and improves extrusion processability without substantially impairing the excellent physical properties of thermoplastic polyurethane elastomers. [Means for solving the problem]

[0008] As a result of various studies conducted to solve the above problems, the inventors of the present invention discovered that by melt-kneading specific multilayer polymer particles into a thermoplastic polyurethane elastomer, the extrusion moldability can be improved while maintaining the flexibility and mechanical properties of the thermoplastic polyurethane elastomer, thus completing the present invention.

[0009] In other words, the present invention encompasses the following embodiments [1] to [7]. [1] A polyurethane resin composition comprising 20 to 99 parts by mass of thermoplastic polyurethane elastomer (A) and 1 to 80 parts by mass of multilayer polymer particles (B), wherein the multilayer polymer particles (B) are as follows (1) to (6): (1) The multilayer polymer particle (B) consists of two or more layers, each having at least one rubber component layer (I) inside and at least one thermoplastic resin component layer (II) on the outermost surface. (2) The rubber component layer (I) is a polymer layer formed by copolymerization of a monomer mixture (i) consisting of 50 to 99.99% by mass of an acrylic acid ester, 49.99 to 0% by mass of another monofunctional monomer copolymerizable with the acrylic acid ester, and 0.01 to 10% by mass of a polyfunctional monomer. (3) The thermoplastic resin component layer (II) is a polymer layer formed by polymerization of monomer (ii) consisting of 40 to 100% by mass of methacrylic acid ester and 60 to 0% by mass of other monomer copolymerizable with the methacrylic acid ester, (4) The number average molecular weight of the outermost polymer of the thermoplastic resin component layer (II) is 30,000 or less by GPC method, (5) The total mass ratio of the rubber component layer (I) to the thermoplastic resin component layer (II) [(I) / (II)] is 30 / 70 to 90 / 10. (6) The average particle diameter of the multilayer polymer particles (B) is 150 nm or less. The conditions are met, Shear rate of thermoplastic polyurethane elastomer (A) 121.6 sec -1 Melt viscosity η(A) of polyurethane resin composition at a shear rate of 121.6 sec -1 A polyurethane resin composition characterized in that the melt viscosity ratio ηr to the melt viscosity η satisfies the following relationship. Melt viscosity ratio ηr(180°C): η(A) / η>1.0 Melt viscosity ratio ηr(200°C): η(A) / η ≤ 1.0 [2] The polyurethane resin composition according to [1], characterized in that it contains 60 to 99 parts by mass of thermoplastic polyurethane elastomer (A) and 1 to 40 parts by mass of multilayer polymer particles (B). [3] A polyurethane resin composition having a Shore A hardness of 60 to 95 measured by a method conforming to JIS K 6253, as described in [1] or [2]. 〔4〕 The polyurethane resin composition according to any one of [1] to [3], which is a resin composition for extrusion molding. 〔5〕 The polyurethane resin composition according to any one of [1] to [3], which is a resin composition for film extrusion. 〔6〕 A method for producing the polyurethane resin composition according to any one of claims 1 to 3, wherein the multilayer structure polymer particles (B) are By copolymerizing a monomer mixture (i) consisting of 50 to 99.99% by mass of an acrylate ester, 49.99 to 0% by mass of another monofunctional monomer copolymerizable with the acrylate ester, and 0.01 to 10% by mass of a polyfunctional monomer, at least one rubber component layer (I) is formed inside; and By polymerizing a monomer (ii) consisting of 40 to 100% by mass of a methacrylate ester and 60 to 0% by mass of another monomer copolymerizable with the methacrylate ester, at least one thermoplastic resin component layer (II) is formed at least on the outermost layer; Including manufacturing by In the polymerization reaction step (S2), the number average molecular weight of the constituent copolymer of the layer (II) constituting at least the outermost layer is 30,000 or less by the GPC method, The mass ratio ((i) / (ii)) of the total amount of the monomer mixture (i) to the total amount of the monomer mixture (ii) is within the range of 30 / 70 to 90 / 10, A manufacturing method, wherein the average particle diameter of the produced multilayer structure polymer particles (B) is 150 nm or less. 〔7〕 A method for producing an extruded body made of the polyurethane resin composition according to any one of [1] to [3], characterized in that the polyurethane resin composition is extruded at a temperature such that the temperature of the molten resin at the die part during extrusion is 200 °C or higher. 〔8〕 A method for manufacturing a film made of the polyurethane resin composition according to any one of [1] to [3], characterized in that the polyurethane resin composition is film-extruded at a temperature such that the temperature of the molten resin at the T-die part during extrusion is 200 °C or higher.

Advantages of the Invention

[0010] According to the present invention, a polyurethane resin composition excellent in flexibility and mechanical properties and suitable for extrusion molding is provided.

Embodiments for Carrying Out the Invention

[0011] One of the major features of the present invention is to control the melt viscosity range of the polyurethane resin composition by adding multilayer structure polymer particles (B) to a thermoplastic polyurethane elastomer (A) in a specific melt viscosity range. That is, when the thermoplastic polyurethane elastomer (A) is melt-molded, at low temperatures, the thermoplastic resin component layer of the multilayer structure polymer particles is plasticized to control the melt viscosity of the polyurethane resin composition to a low viscosity, and at high temperatures, the rubber component layer of the multilayer structure polymer particles does not flow, thereby controlling the melt viscosity of the polyurethane resin composition to a high viscosity. These two effects contribute well and balancefully. From this point, it is considered that a polyurethane resin composition showing good extrusion processability can be provided.

[0012] The polyurethane resin composition of the present invention is a polyurethane resin composition in which the melt viscosity ratio ηr of the melt viscosity η(A) of the thermoplastic polyurethane elastomer (A) to the melt viscosity η of the polyurethane resin composition satisfies the following relationship. By satisfying the following relationship for the melt viscosity ratio ηr, the change in melt viscosity due to temperature change is small, so draw resonance is unlikely to occur. It is possible to achieve both the effect of improving fluidity during low-temperature molding and the effect of reducing drawdown (deterioration of shape due to sagging due to its own weight after sheet / film molding) by suppressing a sharp decrease in melt viscosity due to dissociation of urethane bonds in the thermoplastic polyurethane elastomer during high-temperature molding. The extrusion processability of the polyurethane resin composition is improved and the molding processing temperature range can be widened. Melt viscosity ratio ηr(180°C): η(A) / η>1.0 Melt viscosity ratio ηr(200°C): η(A) / η ≤ 1.0 The melt viscosity ratio ηr (180°C) is preferably greater than 1.0 and 10.0 or less, more preferably 1.2 to 8.0. The melt viscosity ratio ηr (200°C) is preferably 0.10 to 0.95, more preferably 0.20 to 0.90.

[0013] The melt viscosity of this invention is measured using a capillary graph in accordance with JIS K7199, at a shear rate of 121.6 sec. -1 This shows the melt viscosity in that region.

[0014] The thermoplastic polyurethane elastomer (A) used in the present invention is an extrudeable thermoplastic polyurethane elastomer. This thermoplastic polyurethane elastomer can be obtained by reacting a diisocyanate compound with a compound having two or more hydroxyl groups. In particular, an elastomer having a microphase separation structure consisting of a so-called soft segment and a hard segment, composed of a diisocyanate, a long-chain polyol, and a chain extender, is preferably used.

[0015] Examples of diisocyanate compounds for synthesizing the thermoplastic polyurethane elastomer (A) used in the present invention include aliphatic diisocyanates such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate; alicyclic diisocyanates such as 1,4-cyclohexane diisocyanate, isophorone diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate; and aromatic diisocyanates such as p-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, and 4,4'-diphenylmethane diisocyanate. Among these, aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, and 2,6-tolylene diisocyanate are preferred from the viewpoint of mechanical properties.

[0016] Furthermore, examples of compounds having two or more hydroxyl groups include polyester polyols, which are condensation reaction products of dibasic acids such as adipic acid and phthalic acid with glycols such as ethylene glycol and 1,4-butanediol; polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyethylene glycol-polypropylene glycol; polycarbonate polyols, which are reaction products of carbonates such as ethylene carbonate with glycols; and other polyols such as castor oil polyols and polyols using a butadiene skeleton. The polyurethane resin composition of the present invention is more effective against polyether polyols, which have low stability against thermal oxidative degradation, because it improves extrusion processability and widens the molding temperature range.

[0017] The polyol having a number-average molecular weight of 500 to 8,000, and particularly preferably 1,000 to 6,000, is used. Here, the number-average molecular weight of the polyol as used herein is the number-average molecular weight calculated based on the hydroxyl value measured in accordance with JIS K1557.

[0018] Examples of chain extenders include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, bisphenol A, and p-xylylene glycol.

[0019] In the production of the thermoplastic polyurethane elastomer (A) used in the present invention, in addition to the above components, catalysts, molecular weight modifiers, etc., are used as needed. Conventional known methods such as bulk polymerization and solution polymerization can be applied to the production method. For example, in bulk polymerization, there is a one-shot method in which polyol, chain extender, and diisocyanate are polymerized simultaneously, and a prepolymer method in which polyol and diisocyanate are reacted in advance to synthesize a prepolymer, and then chain extender is added and polymerized. Using these methods, it is possible to produce industrially by batch polymerization, band casting, and reaction extrusion.

[0020] The melt viscosity η(A) of the thermoplastic polyurethane elastomer (A) used in the present invention is preferably 500 to 10,000 Pa·s, more preferably 1,000 to 8,000 Pa·s, and even more preferably 1,500 to 5,000 Pa·s, when measured at 180°C. Furthermore, the melt viscosity is preferably 100 to 1,500 Pa·s, more preferably 200 to 1,300 Pa·s, and even more preferably 300 to 1,000 Pa·s, when measured at 200°C. When the melt viscosity at 180°C and 200°C is within the above ranges, the polyurethane resin composition of the present invention exhibits good extrusion processability.

[0021] The melt flow rate (hereinafter referred to as "MFR") of the thermoplastic polyurethane elastomer (A) used in this invention is preferably 0.1 to 50 g / 10 min, and particularly preferably 0.5 to 40 g / 10 min. When the MFR is in the range of 0.1 to 50 g / 10 min, the extrusion processability is good. The MFR of the thermoplastic polyurethane elastomer (A) is the value measured in accordance with JIS K7210 using a melt indexer at a temperature of 190°C and under a load of 2.16 kg.

[0022] The Shore A hardness of the thermoplastic polyurethane elastomer (A) used in this invention is preferably between 70 and 98, and more preferably between 80 and 95. A Shore A hardness in the range of 70 to 98 provides good flexibility. In this specification, Shore A hardness refers to the value measured using a durometer with a Type A indenter, in accordance with JIS K6253.

[0023] The multilayer polymer particle (B) has at least one rubber component layer (I) (hereinafter sometimes simply referred to as "layer (I)") inside and at least one thermoplastic resin component layer (II) (hereinafter sometimes simply referred to as "layer (II)") on the outermost surface. The number of layers of the multilayer polymer particle (B) used in the present invention may be two or more, and may be three or four or more. Examples of layer structures include a two-layer structure of layer (I)-layer (II) from the center; a three-layer structure of layer (I)-layer (I)-layer (II), layer (I)-layer (II)-layer (II), or layer (II)-layer (I)-layer (II); and a four-layer structure such as layer (I)-layer (II)-layer (I)-layer (II). In particular, from the viewpoint of ease of handling, a two-layer structure of layer(I)-layer(II); or a three-layer structure of layer(I)-layer(I)-layer(II) or layer(II)-layer(I)-layer(II) is preferred. "-" means "and".

[0024] The mass ratio (layer(I) / layer(II)) of the total amount of rubber component layer (I) to the total amount of thermoplastic resin component layer (II) must be 30 / 70 to 90 / 10. If the proportion of layer(I) is less than the above range, the flexibility of the polyurethane resin composition of the present invention may be insufficient. If the proportion of layer(I) is greater than the above range, it may become difficult to form a particle structure, and the melt fluidity may decrease, making it difficult to knead with other components and mold the polyurethane resin composition of the present invention. The mass ratio (layer(I) / layer(II)) is preferably 50 / 50 to 90 / 10, more preferably 60 / 40 to 80 / 20.

[0025] Layer (I) must consist of a copolymer comprising 50 to 99.99% by mass of acrylic acid ester monomer units, 49.99% to 0% by mass of other monofunctional monomer units, and 0.01 to 10% by mass of polyfunctional monomer units. The content of acrylic acid ester monomer units is preferably 55 to 99.9% by mass, the content of other monofunctional monomer units is preferably 44.9% to 0% by mass, and the content of polyfunctional monomer units is preferably 0.1 to 2% by mass. If the amount of acrylic acid ester monomer units is less than 50% by mass, the rubber elasticity of the multilayer polymer particles (B) and the weather resistance of the resulting polyurethane resin composition will decrease. If it exceeds 99.99% by mass, the multilayer polymer particles (B) will have difficulty forming a complete layer structure, the melt fluidity will decrease drastically, and melt kneading and molding with other components such as thermoplastic polyurethane elastomer (A) will become difficult. Furthermore, if the amount of polyfunctional monomer units exceeds 10% by mass, the multilayer polymer particles (B) lose their rubber elasticity and become insufficiently flexible, and if it is less than 0.01% by mass, the layer (I) will not be formed as a particle structure.

[0026] The raw material monomers for layer (I) will be described below. Examples of acrylic acid esters include esters of acrylic acid with saturated aliphatic alcohols (preferably C1-C18 saturated aliphatic alcohols), such as methyl acrylate (MA), ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate (BA), isobutyl acrylate, s-butyl acrylate, t-butyl acrylate, pentyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, and octadecyl acrylate; esters of acrylic acid with C5 or C6 alicyclic alcohols, such as cyclohexyl acrylate; esters of acrylic acid with phenols, such as phenyl acrylate; and esters of acrylic acid with aromatic alcohols, such as benzyl acrylate. One or more acrylic acid esters can be used.

[0027] A polyfunctional monomer is a monomer that has two or more carbon-carbon double bonds in its molecule. Examples of polyfunctional monomers include esters of unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and cinnamic acid with unsaturated alcohols such as allyl alcohol and methallyl alcohol; diesters of the aforementioned unsaturated monocarboxylic acids with glycols such as ethylene glycol, butanediol, and hexanediol; and esters of dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and maleic acid with the aforementioned unsaturated alcohols. Specifically, examples include allyl acrylate, methallyl acrylate, allyl methacrylate (ALMA), methallyl methacrylate, allyl cinnamate, methallyl cinnamate, diallyl maleate, diallyl phthalate, diallyl terephthalate, diallyl isophthalate, divinylbenzene, ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, and hexanediol di(meth)acrylate. Among these, allyl methacrylate (ALMA) is preferred. One or more polyfunctional monomers can be used.

[0028] Other monofunctional monomers include esters of methacrylic acid with saturated aliphatic alcohols (preferably C1-C22 saturated aliphatic alcohols), such as methyl methacrylate (MMA), ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, pentyl methacrylate, hexyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, myristyl methacrylate, palmityl methacrylate, stearyl methacrylate, and behenyl methacrylate; esters of methacrylic acid with C5 or C6 alicyclic alcohols, such as cyclohexyl methacrylate; esters of methacrylic acid with phenols, such as phenyl methacrylate; esters of methacrylic acid with aromatic alcohols, such as benzyl methacrylate; styrene (St), α Aromatic vinyl monomers such as methylstyrene, 1-vinylnaphthalene, 3-methylstyrene, 4-propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl)styrene, and halogenated styrenes; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile. Other monofunctional monomers can be used one or more in combination.

[0029] Layer (II) must consist of a copolymer comprising 40 to 100% by mass of methacrylic acid ester monomer units and 60 to 0% by mass of other monomer units. The content of methacrylic acid ester monomer units is preferably 60 to 99% by mass, more preferably 80 to 99% by mass, and the content of other monomer units is preferably 40 to 1% by mass, more preferably 20 to 1% by mass. If the content of methacrylic acid ester monomer units is less than 40% by mass, the compatibility between the multilayer polymer particles (B) and other components such as thermoplastic polyurethane elastomer (A) will decrease, which may result in insufficient dispersion during melt kneading and molding.

[0030] The raw material monomers for layer (II) will be explained below. Examples of methacrylate esters include methyl methacrylate (MMA), ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, pentyl methacrylate, hexyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, dodecyl methacrylate, myristyl methacrylate, palmityl methacrylate, stearyl methacrylate, behenyl methacrylate, octadecyl methacrylate, phenyl methacrylate, and benzyl methacrylate. Among these, methyl methacrylate (MMA) is preferred.

[0031] Other monomers include esters of acrylic acid with saturated aliphatic alcohols (preferably C1-C18 saturated aliphatic alcohols), such as methyl acrylate (MA), ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate (BA), isobutyl acrylate, s-butyl acrylate, t-butyl acrylate, pentyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, and octadecyl acrylate; esters of acrylic acid with C5 or C6 alicyclic alcohols, such as cyclohexyl acrylate; styrene (St), α-methylstyrene, 1- Aromatic vinyl monomers such as vinylnaphthalene, 3-methylstyrene, 4-propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl)styrene, and halogenated styrenes; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; maleimide monomers such as maleimide, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-(p-bromophenyl)maleimide, and N-(chlorophenyl)maleimide; and polyfunctional monomers as exemplified in layer (I) are examples. Among these, alkyl acrylates such as methyl acrylate (MA), ethyl acrylate, and n-butyl acrylate (BA) are preferred.

[0032] In the multilayer polymer particles (B) used in the present invention, the number-average molecular weight of the copolymer constituting at least the outermost layer of the particle among the layers (II) contained therein must be 30,000 or less, preferably 29,000 or less, more preferably 28,000 or less, and even more preferably 25,000 or less, based on measurement by GPC (gel permeation chromatography). If the number-average molecular weight exceeds 30,000, the flexibility of the molded product obtained by molding the multilayer polymer particles (B) will be insufficient, and the melt fluidity may also decrease. There is no strict lower limit for the number-average molecular weight, but from the viewpoint of the passability of the multilayer polymer particles (B) through the production process, it is preferable that the number-average molecular weight does not fall below 1,000. From the viewpoint of achieving both flexibility and passability through the production process, it is particularly preferable to have the number-average molecular weight in the range of 3,000 to 20,000.

[0033] The average particle diameter of the multilayer polymer particles (B) used in this invention must be 150 nm or less. If the average particle diameter of the multilayer polymer particles (B) exceeds 150 nm, the flexibility will be insufficient. In addition, the melt flowability may be poor. There is no particular lower limit to the average particle diameter, but from the viewpoint of easily forming a predetermined layer structure of the multilayer polymer particles (B), an average particle diameter of 30 nm or more is preferable. An average particle diameter of 80 to 120 nm is even more preferable. The average particle diameter of the multilayer polymer particles (B) can be measured by light scattering using a laser diffraction / scattering particle size distribution analyzer LA-950V2 manufactured by Horiba, Ltd. by sampling the latex during the polymerization of the multilayer polymer particles. In the case of a polyurethane resin composition, it can also be measured by a transmission electron microscope.

[0034] As for the multilayer polymer particles (B), from the viewpoint of physical properties and ease of manufacture, a multilayer polymer particle (BX) having a three-layer structure consisting of a first rubber component layer (I) (rubber component layer (Ia)), a second rubber component layer (I) (rubber component layer (Ib)), and a thermoplastic resin component layer (II) from the center is preferred.

[0035] From the viewpoint of achieving both flexibility and other mechanical properties of the polyurethane resin composition of the present invention, the mass ratio ((Ia) / (Ib)) of the rubber component layer (Ia) to the rubber component layer (Ib) is preferably 5 / 95 to 95 / 5, more preferably 20 / 80 to 80 / 20.

[0036] From the viewpoint of achieving both flexibility and other mechanical properties of the polyurethane resin composition of the present invention, the content (C AE (Ia) (mass%)) of the acrylate monomer unit in the rubber component layer (Ia) is preferably higher than the content (C AE (Ib) (mass%)) of the acrylate monomer unit in the rubber component layer (Ib) (C AE (Ia) > C AE (Ib)). Further, the amount obtained by subtracting the content (C AE (Ia) (mass%)) of the acrylate monomer unit in the rubber component layer (Ia) from the content (C AE (Ib) (mass%)) of the acrylate monomer unit in the rubber component layer (Ib) is preferably 3 mass% or more (3 ≤ [C AE (Ia) - C AE (Ib)]), and more preferably 4 to 30 mass% (4 ≤ [C AE (Ia) - C AE (Ib)] ≤ 30).

[0037] The multilayer structure polymer particles (B) can be produced by performing the polymerization reaction step (S1) for forming the rubber component layer (I) and the polymerization reaction step (S2) for forming the thermoplastic resin component layer (II) in the stacking order.

[0038] In polymerization reaction step (S1), monomer mixture (i) corresponding to the copolymer composition of the rubber component layer (I) is copolymerized by a known method. Similarly, in polymerization reaction step (S2), monomer mixture (ii) corresponding to the copolymer composition of the thermoplastic resin component layer (II) is copolymerized by a known method. In polymerization reaction step (S2), the polymerization conditions are adjusted so that the Mn of the constituent copolymer of at least the outermost layer (II) is 30,000 or less. Furthermore, the polymerization conditions are adjusted so that the mass ratio ((i) / (ii)) of the total amount of monomer mixture (i) to the total amount of monomer mixture (ii) is within the range of 30 / 70 to 90 / 10, and the average particle size of the multilayer polymer particles (B) finally obtained by polymerization reaction steps (S1) and (S2) is 150 nm or less.

[0039] In the polymerization reaction step (S2) that forms at least the outermost thermoplastic resin component layer (II), it is preferable to use a molecular weight modifier in a proportion of 0.4 to 10% by mass relative to the monomer mixture (ii). The amount of molecular weight modifier used is more preferably 0.4 to 5% by mass, and particularly preferably 0.6 to 2% by mass, relative to the monomer mixture (ii). Generally, in the production of multilayer polymer particles, the amount of molecular weight modifier used in the polymerization reaction step that forms the outermost thermoplastic resin component layer is about 0 to 0.3% by mass relative to the monomer (mixture). However, our findings indicate that if the amount of molecular weight modifier used is 0.4% by mass or more, the Mn of the thermoplastic resin component constituting the outermost layer can be stably kept below 30,000, thus stably achieving both flexibility and moldability in the polyurethane resin composition. Furthermore, even if the amount of molecular weight modifier used exceeds 10% by mass, no further improvement in flexibility can be obtained, and it only results in a large amount of unnecessary residual molecular weight modifier.

[0040] Examples of molecular weight modifiers include mercaptans such as n-octyl mercaptan, t-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, and mercaptoethanol; terpene mixtures consisting of terpinolene, dipentene, t-terpinene, and small amounts of other cyclic terpenes; and halogenated hydrocarbons such as chloroform and carbon tetrachloride. Among these, alkyl mercaptans such as n-octyl mercaptan are preferred. One or more molecular weight modifiers can be used.

[0041] The polymerization method for the multilayer polymer particles (B) is not particularly limited, and known methods such as emulsion polymerization, suspension emulsion polymerization, solution polymerization, and combinations thereof can be employed.

[0042] Below, as an example, we will describe suitable polymerization conditions for multilayer polymer particles (B) produced by emulsion polymerization. The polymerization temperature is generally between 0 and 100°C. Examples of emulsifiers include alkali metal salts of fatty acids such as sodium oleate, sodium laurate, and sodium stearate; sulfate esters of fatty alcohols such as sodium lauryl sulfate; rosinates such as potassium rosinate; and alkylaryl sulfonic acids such as dodecylbenzenesulfonic acid. One or more emulsifiers may be used. Radical polymerization initiators are commonly used as polymerization initiators. Peroxides such as persulfates, azobisisobutyronitrile, and benzoyl peroxide can be used alone as radical polymerization initiators. Redox initiators can also be used, which are combinations of organic hydroperoxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, and paramenthane hydroperoxide with reducing agents such as transition metal salts. The average particle size of the multilayer polymer particles (B) can be controlled to 150 nm or less by adjusting polymerization conditions such as the amount of emulsifier added. The multilayer polymer particles (B) after polymerization can be separated and obtained from the reaction system by known methods such as acid precipitation, salting out, spray drying, and freeze-coagulation.

[0043] The melt viscosity of the multilayer polymer particles (B) used in the present invention is preferably 1,000 to 4,000 Pa·s, more preferably 1,200 to 3,500 Pa·s, and even more preferably 1,500 to 3,000 Pa·s, as measured at 180°C. Furthermore, the melt viscosity is preferably 800 to 3,000 Pa·s, more preferably 900 to 2,500 Pa·s, and even more preferably 1,000 to 2,000 Pa·s, as measured at 200°C. When the melt viscosity at 180°C and 200°C is within the above ranges, the polyurethane resin composition of the present invention exhibits good extrusion processability.

[0044] The melt flow rate (hereinafter referred to as "MFR") of the multilayer polymer particles (B) used in this invention is preferably 1.0 to 50 g / 10 min, and particularly preferably 5.0 to 20 g / 10 min. When the MFR is in the range of 1.0 to 50 g / 10 min, the extrusion processability is good. The MFR for the multilayer polymer particles (B) is the value measured in accordance with JIS K7210 using a melt indexer at a temperature of 230°C and a load of 10 kg.

[0045] The Shore A hardness of the multilayer polymer particles (B) used in this invention is preferably between 60 and 95, and more preferably between 70 and 90. A Shore A hardness in the range of 60 to 95 provides good flexibility. In this specification, Shore A hardness refers to the value measured using a durometer with a Type A indenter, in accordance with JIS K6253.

[0046] The polyurethane resin composition in the present invention comprises a thermoplastic polyurethane elastomer (A) and multilayer polymer particles (B). The mass ratio ((A) / (B)) of the thermoplastic polyurethane elastomer (A) to the multilayer polymer particles (B) is 20 / 80 to 99 / 1 from the viewpoint of achieving both flexibility and extrudeability. The mass ratio ((A) / (B)) is preferably 60 / 40 or more, more preferably 70 / 30 or more. The mass ratio ((A) / (B)) is preferably 97 / 3 or less, more preferably 95 / 5 or less, and below this upper limit, the ηr (200℃) can be reduced.

[0047] The method of mixing the thermoplastic polyurethane elastomer (A) and the multilayer polymer particles (B) is not particularly limited, but a melt mixing method is preferred. In the melt mixing method, a melt mixer such as a single-screw or multi-screw mixer, an open roll mixer, a Banbury mixer, and a kneader can be used, and the melt mixing can be carried out in an inert gas atmosphere such as nitrogen gas, argon gas, and helium gas, if necessary.

[0048] The polyurethane resin composition of the present invention may further contain a methacrylic resin in addition to the thermoplastic polyurethane elastomer (A) and multilayer polymer particles (B). The number-average molecular weight (Mn) of the methacrylic resin, as measured by the GPC method, is preferably 10,000 to 100,000, more preferably 15,000 to 50,000. When a methacrylic resin with Mn within the above range is used, the polyurethane resin composition of the present invention exhibits better moldability. The content of the methacrylic resin is not particularly limited, but from the viewpoint of improving the flexibility and moldability of the polyurethane resin composition of the present invention, it is preferably 1 to 20 parts by mass, more preferably 1 to 10 parts by mass, per 100 parts by mass of the total amount of thermoplastic polyurethane elastomer (A) and multilayer polymer particles (B).

[0049] A methacrylic resin is a resin containing methyl methacrylate (MMA) monomer units. The methacrylic resin may be a homopolymer of MMA (polymethyl methacrylate (PMMA)) or a copolymer of multiple monomers containing MMA. A preferred methacrylic resin is a methacrylic resin (CX) consisting of 40 to 100% by mass (preferably 70 to 100% by mass) of MMA units and 60 to 0% by mass (preferably 30 to 0% by mass) of other monomer units copolymerizable with MMA.

[0050] Other monomers copolymerizable with MMA include other methacrylate esters of MMA. Such methacrylate esters include alkyl methacrylates such as ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, and dodecyl methacrylate; 1-methylcyclopentyl methacrylate, cyclohexyl methacrylate, cycloheptyl methacrylate, cyclooctyl methacrylate, and tricyclo[5.2.1.0 2,6 Examples include cycloalkyl methacrylates such as deca-8-yl methacrylate; aryl methacrylates such as phenyl methacrylate; and aralkyl methacrylates such as benzyl methacrylate. From the viewpoint of availability, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and t-butyl methacrylate are preferred.

[0051] Other monomers mentioned above include monomers other than methacrylic acid esters. Examples of such other monomers include acrylic acid esters such as methyl acrylate (MA), ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate (BA), isobutyl acrylate, t-butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, stearyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, cyclohexyl acrylate, 2-methoxyethyl acrylate, 3-methoxybutyl acrylate, trifluoromethyl acrylate, trifluoroethyl acrylate, pentafluoroethyl acrylate, glycidyl acrylate, allyl acrylate, phenyl acrylate, toluyl acrylate, benzyl acrylate, isobornyl acrylate, and 3-dimethylaminoethyl acrylate. In particular, from the viewpoint of availability, acrylic acid esters such as methyl acrylate (MA), ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate (BA), isobutyl acrylate, and t-butyl acrylate are preferred, methyl acrylate (MA) and ethyl acrylate are more preferred, and methyl acrylate (MA) is particularly preferred.

[0052] The polyurethane resin composition of the present invention may optionally contain other polymers in addition to the thermoplastic polyurethane elastomer (A), multilayer polymer particles (B), and methacrylic resin, as long as the effects of the present invention are not impaired. Other polymers include olefin resins such as polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1, and polynorbornene; ethylene ionomers; styrene resins such as polystyrene, styrene-maleic anhydride copolymer, high-impact polystyrene, AS resin, ABS resin, AES resin, AAS resin, ACS resin, and MBS resin; methyl methacrylate-styrene copolymer; ester resins such as polyethylene terephthalate and polybutylene terephthalate; amide resins such as nylon 6, nylon 66, and polyamide elastomers; polyphenylene sulfide, polyether ether ketone, Examples include polysulfone, polyphenylene oxide, polyimide, polyetherimide, polycarbonate, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyacetal, and other thermoplastic resins such as phenoxy resins; thermosetting resins such as phenolic resins, melamine resins, silicone resins, and epoxy resins; polyurethane; modified polyphenylene ether; silicone-modified resin; acrylic rubber, silicone rubber; styrene-based thermoplastic elastomers such as SEPS, SEBS, and SIS; and olefin rubbers such as IR, EPR, and EPDM. One or more of these polymers may be used.

[0053] The polyurethane resin composition of the present invention may contain various additives as needed. Examples of additives include antioxidants, heat degradation inhibitors, ultraviolet absorbers, light stabilizers, lubricants, mold release agents, polymer processing aids, antistatic agents, flame retardants, dyes and / or pigments, light diffusers, matting agents, anti-adhesion agents, impact resistance modifiers, and phosphors. The content of these additives can be appropriately set within a range that does not impair the effects of the present invention. For example, per 100 parts by mass of the polyurethane resin composition, it is preferable that the content of antioxidants is 0.01 to 1 part by mass, the content of ultraviolet absorbers is 0.01 to 3 parts by mass, the content of light stabilizers is 0.01 to 3 parts by mass, the content of lubricants is 0.01 to 3 parts by mass, the content of dyes and / or pigments is 0.01 to 3 parts by mass, and the content of anti-adhesion agents is 0.001 to 1 part by mass.

[0054] When the polyurethane resin composition of the present invention contains other polymers and / or additives, they may be added during the polymerization of the thermoplastic polyurethane elastomer (A) and / or multilayer polymer particles (B), or during the mixing of the thermoplastic polyurethane elastomer (A) and multilayer polymer particles (B), or after the thermoplastic polyurethane elastomer (A) and multilayer polymer particles (B) have been mixed.

[0055] The melt viscosity η of the polyurethane resin composition of the present invention is preferably 500 to 4,000 Pa·s, more preferably 800 to 3,000 Pa·s, and even more preferably 1,000 to 2,500 Pa·s, as measured at 180°C. Furthermore, the melt viscosity η is preferably 200 to 1,000 Pa·s, more preferably 300 to 800 Pa·s, and even more preferably 400 to 700 Pa·s, as measured at 200°C. When the melt viscosity at 180°C and 200°C falls within the above ranges, the polyurethane resin composition of the present invention exhibits good extrusion processability.

[0056] The melt flow rate (hereinafter referred to as "MFR") of the polyurethane resin composition of the present invention is preferably 0.1 to 50 g / 10 min, and more preferably 0.5 to 40 g / 10 min. When the MFR is in the range of 0.1 to 50 g / 10 min, the extrusion processability is good. The MFR in the polyurethane resin composition is the value measured using a melt indexer in accordance with JIS K7210, at a temperature of 190°C and a load of 2.16 kg.

[0057] The Shore A hardness of the polyurethane resin composition of the present invention is preferably 60 to 95, and more preferably 65 to 90. A Shore A hardness in the range of 60 to 95 indicates good flexibility. In this specification, Shore A hardness refers to the value measured using a durometer with a Type A indenter, in accordance with JIS K6253.

[0058] The polyurethane resin composition of the present invention exhibits excellent extrusion moldability because the melt viscosity ratio ηr between the melt viscosity η(A) of the thermoplastic polyurethane elastomer (A) and the melt viscosity η of the polyurethane resin composition is within a specific range. Therefore, for example, in film molding using the T-die method, the melt viscosity is maintained appropriately over a wide molding temperature range, making it less likely to cause appearance defects such as melt fractures, and less likely to cause drawdown, allowing for a higher maximum film take-up speed and thus excellent productivity. Furthermore, molding at low temperatures is possible, which also suppresses the generation of grease due to burning and thermal decomposition. Furthermore, the polyurethane resin composition of the present invention can possess excellent properties such as flexibility and mechanical properties inherent to thermoplastic polyurethane elastomers. The polyurethane resin composition of the present invention contains specific multilayer polymer particles (B), and therefore can maintain good flexibility and mechanical properties. Because the polyurethane resin composition of the present invention has excellent flexibility, the resulting film has a large tensile elongation and is difficult to break.

[0059] As described above, the present invention provides a polyurethane resin composition that is excellent in flexibility, mechanical properties, and extrusion moldability.

[0060] By molding the polyurethane resin composition of the present invention described above, molded articles of any shape, such as pellets, sheets, films, pipes, fibers, hollows, and boxes, can be obtained. Examples of molding methods include extrusion molding methods such as shape extrusion molding, extruded sheet molding, T-dye lamination molding, inflation molding, and extruded coating; injection molding methods such as insert injection molding, two-color injection molding, core-back injection molding, sandwich injection molding, and injection press molding; blow molding; calendering; press molding; slush molding; hollow molding; vacuum molding; and foam molding.

[0061] One form of a molded article is a film. Generally, articles with a thickness of 5 to 200 μm are mainly classified as "films," and those thicker than 200 μm are mainly classified as "sheets." However, in this specification, films and sheets are not clearly distinguished, and both are referred to collectively as "films." For applications of "films" according to the general classification, a thickness of 8 to 200 μm is preferred. For applications of "sheets" according to the general classification, a thickness of 0.2 to 4.0 mm is preferred.

[0062] As a film forming method (film formation method), extrusion molding is preferred. As a melt extrusion method, T-die method and inflation method are examples, and T-die method is preferred from the viewpoint of thickness accuracy and productivity. The melt extrusion temperature is preferably 130 to 240°C. From the viewpoint of suppressing thermal decomposition of thermoplastic polyurethane elastomer, it is preferable to extrude at a temperature at which the cylinder temperature of the extruder is 200°C or less, and it is preferable that ηr > 1.0. Furthermore, from the viewpoint of thinning and improving productivity, it is preferable to extrude at a temperature at which the molten resin temperature in the die section is 200°C or higher, and it is preferable that ηr ≤ 1.0. In particular, from the viewpoint of thinning and improving productivity, it is preferable to extrude at a temperature at which the molten resin temperature in the T-die section is 200°C or higher, and it is preferable that ηr ≤ 1.0. As an extruder, single-screw extruders and multi-screw extruders with two or more screws are examples.

[0063] The T-die method is a film forming method in which a molten resin composition is spread to a desired film width with a substantially uniform thickness, extruded into a film through a slit-shaped die (lip), and cooled by contacting it with a cooling roll. Generally, in the T-die method, it is desirable to set the rotation speed of the cooling roll (film take-up speed) relatively high in order to thin the film and improve productivity. However, in this case, depending on the composition, unevenness may occur in the width and thickness of the film, and the film may warp or break. The polyurethane resin composition of the present invention has excellent extrusion moldability. Therefore, even when the film take-up speed is set relatively high in film formation by the T-die method, unevenness in the width and thickness of the film is less likely to occur, and the film is less likely to warp or break. Accordingly, the polyurethane resin composition of the present invention has excellent film productivity.

[0064] Molded articles (including films) made from the polyurethane resin composition of the present invention generally have excellent flexibility and are therefore suitable for use as soft components in fields such as automotive interior and exterior components, home appliance components, wire insulation, medical components, general merchandise, footwear, and transport belts. [Examples]

[0065] The following describes manufacturing examples, embodiments, and comparative examples according to the present invention.

[0066] [Evaluation items and evaluation methods] The evaluation items and evaluation methods for the manufacturing examples, examples, and comparative examples are as follows.

[0067] (Average particle size of multilayer polymer particles) The average particle size of the multilayer polymer particles was determined by dynamic light scattering using a DLS-600 light scattering photometer manufactured by Otsuka Electronics Co., Ltd., with samples taken from latex after polymerization was complete, and then analyzed by the cumulant method.

[0068] (Number-average molecular weight of the outermost layer of multilayer polymer particles) The number-average molecular weight of the polymer components constituting the outermost layer of multilayer polymer particles was measured by GPC using a solution obtained by thoroughly stirring a sample of multilayer polymer particles in toluene at room temperature and then centrifuging it. In this invention, the value obtained was considered to be the number-average molecular weight of the polymer constituting the outermost layer.

[0069] (Melting viscosity) The resin compositions shown in the Examples and Comparative Examples were extruded using a capillary rheometer (Capillograph 1D, manufactured by Toyo Seiki Seisakusho Co., Ltd.) at 180°C and 200°C from a capillary with a diameter of 1 mmΦ and a length of 40 mm at a piston speed of 10 mm / min (shear rate of 121.6 sec), and the values ​​were evaluated from the shear stress generated during this process.

[0070] (Shore A hardness) The resin compositions shown in the Examples and Comparative Examples were placed in a mold and press-molded at 200°C to obtain press sheets with a thickness of 6 mm. The obtained press sheets were measured using an Asuka Rubber Hardness Tester Type A (manufactured by Polymer Instruments Co., Ltd.) in accordance with JIS K6253.

[0071] (Tensile elongation) The resin compositions shown in the Examples and Comparative Examples were placed in a mold and press-molded at 200°C to obtain press sheets with a thickness of 2 mm. The obtained press sheets were punched out into dumbbell-shaped No. 3 (JIS K6251) and measured according to JIS K6253 using an Autograph (Shimadzu Corporation "AG-1S"). Under conditions of 23°C / 50% relative humidity, the specimen was uniaxially stretched at a tensile speed of 300 mm / min, and the elongation at the time of fracture was determined as the tensile elongation.

[0072] (Moldability) The resin compositions shown in the Examples and Comparative Examples were placed in a mold and press-molded at 200°C to obtain a press sheet with a thickness of 1 mm. The obtained press sheet was punched out into a cylindrical shape with a diameter of 8 mm, and the storage modulus G' was measured using a rotary rheometer (TA Instruments "DISCOVERY HR-2") with an 8 mm parallel plate and a frequency of 1 Hz at temperatures from 25 to 230°C (heating rate: 3°C / min). From the storage modulus G'(30°C) at 30°C and the storage modulus G'(200°C) at 200°C, the moldability was evaluated using the following formula. Here, moldability refers to items to which entropy elasticity contributes, such as drawdown properties and draw resonance properties. Pass:G'(200℃) / G'(30℃)×100≧0.1% Fail:G'(200℃) / G'(30℃)×100<0.1%

[0073] (Situation regarding eye discharge) The resin compositions shown in the Examples and Comparative Examples were extruded using a single-screw film extruder capable of forming sheets approximately 15 cm wide. The die thickness was adjusted to 0.3 mm, and the screw rotation speed was adjusted to achieve a discharge rate of 35 kg / hr. During this process, the occurrence of "die residue" near the die was visually confirmed 10 minutes after the start of extrusion. The optimal temperature conditions for cylinder and die temperatures were determined from the melt viscosity (shear rate 121.6 / sec) measured with a capillary rheometer. Specifically, the optimal temperature condition was set to the temperature at which the melt viscosity reached 1000 Pa·s at a shear rate of 121.6 / sec, based on melt viscosity values ​​measured at different temperatures. The occurrence of die residue was evaluated based on the following evaluation criteria. A: No eye discharge was observed. B: There is some eye discharge near the eye, but no detached discharge has been observed. C: A large amount of eye discharge was present, and some of it was mixed into the film.

[0074] (Film appearance) The resin compositions shown in the Examples and Comparative Examples were extruded using a single-screw film extruder capable of forming a film approximately 150 mm wide. The die thickness was adjusted to 0.3 mm, and the screw rotation speed was adjusted to achieve a discharge rate of 35 kg / hr. The optimal temperature conditions for cylinder and die temperatures were determined from the melt viscosity (shear rate 121.6 / sec) measured with a capillary rheometer. Specifically, the optimal temperature condition was set to the temperature at which the melt viscosity was 1000 Pa·s at a shear rate of 121.6 / sec, based on melt viscosity values ​​measured at different temperatures. The central part (100 mm wide x 5 m long) of the obtained film was visually evaluated according to the following criteria. The evaluation criteria are as follows. Pass: No significant defects such as die lines or melt fractures were observed. Fail: Any of the following noticeable defects are observed: die lines, melt fracture, etc.

[0075] (raw materials) In the following examples and comparative examples, the following thermoplastic polyurethane elastomer (A) was used. Polyurethane thermoplastic elastomer (A-1): "Pandex T-1180" manufactured by DIC Covestropolymer Co., Ltd. was used. This product is an adipate ester-based polyurethane thermoplastic elastomer. Polyurethane thermoplastic elastomer (A-2): "Pandex T-8190" manufactured by DIC Covestropolymer Co., Ltd. was used. This product is an ether-based polyurethane thermoplastic elastomer.

[0076] The monomer names and their abbreviations (in parentheses) used in the manufacturing examples are shown below: Methyl methacrylate (MMA), n-butyl acrylate (BA), methyl acrylate (MA), styrene (St), and allyl methacrylate (ALMA).

[0077] (Production example 1: Multilayer structure polymer particles (B-1)) Under a nitrogen atmosphere, 150 parts by mass of distilled water, 1.3 parts by mass of emulsifier (Kao Corporation's "Neopelex G-15"), and 1.0 part by mass of dispersant (Kao Corporation's "Poise 520") were added to a polymerizer equipped with a stirring blade, a condenser, and a dropping funnel, and heated to 80°C to dissolve uniformly. Then, at the same temperature, 0.05 parts by mass of a 3% aqueous solution of potassium peroxodisulfate was added, and a mixture consisting of 41.25 parts by mass of n-butyl acrylate (BA) as an acrylic ester monomer, 8.75 parts by mass of styrene (St) as another monofunctional monomer, 0.3 parts by mass of allyl methacrylate (ALMA) as a polyfunctional monomer, and 0.25 parts by mass of surfactant (ADEKA Corporation's "Adekacol CS-141E") was added dropwise from the dropping funnel over 60 minutes to form the first layer (layer (Ia)). After the dropping was complete, the reaction was continued at 80°C for another hour, and gas chromatography confirmed that more than 99% of each monomer had been consumed.

[0078] Next, 0.02 parts by mass of a 3% aqueous solution of potassium peroxodisulfate was added to the obtained copolymer latex. Then, a mixture consisting of 15.81 parts by mass of n-butyl acrylate (BA) as an acrylic ester monomer, 3.19 parts by mass of styrene (St) as another monofunctional monomer, 1.0 part by mass of methyl methacrylate (MMA) as another monofunctional monomer, 0.16 parts by mass of allyl methacrylate (ALMA) as a polyfunctional monomer, and 0.1 parts by mass of a surfactant ("Adekacol CS-141E") was added dropwise from a dropping funnel over 40 minutes to form the second layer (layer (Ib)). After the dropwise addition was complete, the reaction was continued at 80°C for another hour, and it was confirmed by gas chromatography that more than 99% of each monomer had been consumed.

[0079] Next, 0.03 parts by mass of a 3% aqueous solution of potassium peroxodisulfate was added to the obtained copolymer latex. Then, a mixture consisting of 28.5 parts by mass of methyl methacrylate (MMA) as a methacrylate monomer, 1.5 parts by mass of methyl acrylate (MA) as another monomer, 0.3 parts by mass of n-octyl mercaptan, and 0.15 parts by mass of a surfactant ("Adekacol CS-141E") was added dropwise from a dropping funnel over 40 minutes to form the third layer (layer (II)). After the dropwise addition was complete, the reaction was continued at 80°C for another hour, and polymerization was terminated when it was confirmed by gas chromatography that more than 99.9% of each monomer had been consumed. The average particle size of the particles in the obtained latex, as determined by light scattering, was 100 nm.

[0080] The obtained latex was cooled at -30°C for 24 hours to induce freeze-aggregation, and the aggregate was then thawed and removed. It was dried under reduced pressure at 50°C for 2 days to obtain powdered, three-layered multilayer polymer particles (B-1). The number-average molecular weight (Mn) of the polymer components constituting the outermost layer was 25,000. The particle structure is shown in Table 1. "Layer ratio" indicates the mass ratio of the first, second, and third layers.

[0081] (Production example 2: Multilayer structure polymer particles (B-2)) Under a nitrogen atmosphere, 200 parts by mass of distilled water, 1.3 parts by mass of emulsifier (Kao Corporation's "Neopelex G-15"), and 0.05 parts by mass of sodium carbonate were added to a polymerizer equipped with a stirring blade, condenser, and dropping funnel, and heated to 80°C until uniformly dissolved. Next, at the same temperature, 0.01 parts by mass of a 3% aqueous solution of potassium peroxodisulfate was added, and then a mixture consisting of 2.52 parts by mass of n-butyl acrylate (BA) as an acrylic ester monomer, 2.52 parts by mass of methyl methacrylate (MMA) as another monofunctional monomer, and 0.01 parts by mass of allyl methacrylate (ALMA) as a polyfunctional monomer was added dropwise from the dropping funnel over 30 minutes to form the first layer (layer (Ia)). After the dropwise addition was complete, the reaction was continued at 80°C for another 30 minutes, and it was confirmed by gas chromatography that more than 99% of each monomer had been consumed.

[0082] Next, 0.09 parts by mass of a 3% aqueous solution of potassium peroxodisulfate was added to the obtained copolymer latex. Then, a mixture consisting of 28.50 parts by mass of n-butyl acrylate (BA) as an acrylic ester monomer, 1.52 parts by mass of methyl methacrylate (MMA) as another monofunctional monomer, and 0.9 parts by mass of allyl methacrylate (ALMA) as a polyfunctional monomer was added dropwise from a dropping funnel over 50 minutes to form the second layer (layer (Ib)). After the dropwise addition was complete, the reaction was continued at 80°C for another 30 minutes, and it was confirmed by gas chromatography that more than 99% of each monomer had been consumed.

[0083] Next, a mixture consisting of 56.82 parts by mass of methyl methacrylate (MMA) as a methacrylate monomer, 8.12 parts by mass of n-butyl acrylate (BA) as another monomer, and 0.19 parts by mass of n-octyl mercaptan was added dropwise from a dropping funnel over 100 minutes to form the third layer (layer (II)). After the addition was complete, the reaction was continued at 80°C for another hour, and polymerization was terminated when it was confirmed by gas chromatography that more than 99.9% of each monomer had been consumed. The average particle size of the resulting latex, as determined by light scattering, was 100 nm.

[0084] The above latex was cooled at -30°C for 24 hours to induce freeze-aggregation, and the aggregate was then thawed and removed. It was dried under reduced pressure at 50°C for 2 days to obtain powdery, three-layered multilayer polymer particles (B-2). The number-average molecular weight (Mn) of the polymer components constituting the outermost layer was 33,000. The particle structure is shown in Table 1.

[0085] (Production Example 3: Multilayer polymer particles (B-3)) Under a nitrogen atmosphere, 100 parts by mass of distilled water, 0.02 parts by mass of emulsifier (Nikko Chemicals "Nikkol ECT-3NEX"), and 0.1 parts by mass of sodium carbonate were added to a polymerizer equipped with a stirring blade, a condenser, and a dropping funnel, and heated to 80°C to dissolve uniformly. Then, at the same temperature, 0.035 parts by mass of a 3% aqueous solution of potassium peroxodisulfate was added, and a mixture consisting of 2.11 parts by mass of methyl acrylate (MA) as an acrylic acid ester monomer, 32.89 parts by mass of methyl methacrylate (MMA) as another monofunctional monomer, 0.07 parts by mass of allyl methacrylate (ALMA) as a polyfunctional monomer, and 0.25 parts by mass of emulsifier (Nikko Chemicals "Nikkol ECT-3NEX") was added dropwise from the dropping funnel over 60 minutes to form the first layer (layer (Ia)). After the dropwise addition was complete, the reaction was continued at 80°C for another 40 minutes, and gas chromatography confirmed that more than 99% of each monomer had been consumed.

[0086] Next, 0.045 parts by mass of a 3% aqueous solution of potassium peroxodisulfate was added to the obtained copolymer latex. Then, a mixture consisting of 37.0 parts by mass of n-butyl acrylate (BA) as an acrylic ester monomer, 8.0 parts by mass of styrene (St) as another monofunctional monomer, 0.9 parts by mass of allyl methacrylate (ALMA) as a polyfunctional monomer, and 0.12 parts by mass of an emulsifier (Nikko Chemicals "Nikkol ECT-3NEX") was added dropwise from a dropping funnel over 70 minutes to form the second layer (layer (Ib)). After the dropwise addition was complete, the reaction was continued at 80°C for another 90 minutes, and it was confirmed by gas chromatography that more than 99% of each monomer had been consumed.

[0087] Next, 0.02 parts by mass of a 3% aqueous solution of potassium peroxodisulfate was added to the obtained copolymer latex. Then, a mixture consisting of 18.80 parts by mass of methyl methacrylate (MMA) as a methacrylate monomer, 1.2 parts by mass of methyl acrylate (MA) as another monomer, and 0.04 parts by mass of n-octyl mercaptan was added dropwise from a dropping funnel over 30 minutes to form the third layer (layer (II)). After the dropwise addition was complete, the reaction was continued at 80°C for another 40 minutes, and polymerization was terminated when it was confirmed by gas chromatography that more than 99.9% of each monomer had been consumed. The average particle size of the particles in the obtained latex, as determined by light scattering, was 230 nm.

[0088] The above latex was cooled at -30°C for 24 hours to induce freeze-aggregation, and the aggregate was then thawed and removed. It was dried under reduced pressure at 50°C for 2 days to obtain powdery, three-layered multilayer polymer particles (B-3). The number-average molecular weight (Mn) of the polymer components constituting the outermost layer was 31,000. The particle structure is shown in Table 1.

[0089] [Table 1]

[0090] (Examples 1-6) Polyurethane thermoplastic elastomers (A-1) to (A-2) and multilayer polymer particles (B-1) obtained in Production Example 1 were melt-kneaded in a 20 mmφ twin-screw extruder at a cylinder temperature of 200°C in the ratios shown in Table 2. The melt-kneaded mixture was then extruded to obtain a pellet-shaped polyurethane resin composition. The film extrusion temperature conditions were 190°C for the cylinder and 200°C for the T-die. The composition and physical property evaluation results of the polyurethane resin composition are shown in Table 2.

[0091] (Comparative Examples 1-2) 70 parts by mass of polyurethane thermoplastic elastomer (A-1) and 30 parts by mass of multilayer polymer particles (B-2) to (B-3) obtained in Production Examples 2 to 3 were melt-kneaded in a 20 mmφ twin-screw extruder at a cylinder temperature of 200°C, and the melt-kneaded mixture was extruded to obtain a pellet-shaped polyurethane resin composition. The film extrusion temperature conditions were 190°C for the cylinder and 200°C for the T-die. The composition and physical property evaluation results of the polyurethane resin composition are shown in Table 2.

[0092] (Comparative Examples 3-4) 100 parts by mass of polyurethane thermoplastic elastomers (A-1) to (A-2) were melt-kneaded in a 20 mmφ twin-screw extruder at a cylinder temperature of 200°C, and the molten mixture was extruded to obtain a pellet-shaped polyurethane resin composition. The film extrusion temperature conditions were 190°C for the cylinder and 200°C for the T-die. The composition and physical property evaluation results of the polyurethane resin composition are shown in Table 2.

[0093] [Table 2]

[0094] The polyurethane resin compositions of Examples 1 to 6 of the present invention, which include a thermoplastic polyurethane elastomer (A) with a specific melt viscosity range and multilayer polymerized particles (B-1), have a specific melt viscosity range suitable for extrusion molding. As a result, they exhibit excellent moldability during extrusion (suppression of drawdown and draw resonance), no die line or melt fracture occurs, resulting in a good film appearance, and molding is possible at an appropriate extrusion temperature that does not cause thermal decomposition, thus eliminating the generation of die lines. In particular, the polyurethane resin compositions of Examples 1 to 4 of the present invention, which have a high composition ratio of thermoplastic polyurethane elastomer (A), exhibit tensile elongation at break and hardness equivalent to that of thermoplastic polyurethane elastomers, confirming that the excellent mechanical properties and flexibility characteristic of thermoplastic polyurethane elastomers are maintained.

[0095] In contrast, the polyurethane resin compositions of Comparative Examples 1 and 2, which included a thermoplastic polyurethane elastomer (A) within a specific melt viscosity range and multilayer polymerized particles (B-2) to (B-3), experienced a significant decrease in viscosity at high temperatures, resulting in drawdown and film appearance defects such as melt fractures. Furthermore, the tensile elongation at break decreased, leading to poor mechanical performance. Additionally, the thermoplastic polyurethane elastomer (A) alone in Comparative Examples 3 and 4, within a specific melt viscosity range, exhibited poor extrusion moldability and difficulty in molding due to the large temperature dependence of its melt viscosity. This resulted in film appearance defects due to die-line melt fractures and the generation of smear marks. [Industrial applicability]

[0096] The present invention provides a polyurethane resin composition that retains the mechanical properties and flexibility of thermoplastic polyurethane elastomers and exhibits excellent extrusion moldability. Molded articles, films, or sheets made from this composition are suitably used for soft materials such as automotive interior and exterior components, home appliance components, wire insulation, medical components, general merchandise, footwear, and transport belts. Furthermore, since the polyurethane resin composition of the present invention also exhibits excellent adhesion to other resins, it can be used as a soft layer in laminates or as a soft layer component in composite molded products.

Claims

1. A polyurethane resin composition comprising 20 to 99 parts by mass of thermoplastic polyurethane elastomer (A) and 1 to 80 parts by mass of multilayer polymer particles (B), wherein the multilayer polymer particles (B) are as follows (1) to (6): (1) The multilayer polymer particle (B) consists of two or more layers, each having at least one rubber component layer (I) inside and at least one thermoplastic resin component layer (II) on the outermost surface. (2) The rubber component layer (I) is a polymer layer formed by copolymerization of a monomer mixture (i) consisting of 50 to 99.99% by mass of an acrylic acid ester, 49.99 to 0% by mass of another monofunctional monomer copolymerizable with the acrylic acid ester, and 0.01 to 10% by mass of a polyfunctional monomer. (3) The thermoplastic resin component layer (II) is a polymer layer formed by polymerization of monomer (ii) consisting of 40 to 100% by mass of methacrylic acid ester and 60 to 0% by mass of other monomer copolymerizable with the methacrylic acid ester, (4) The number average molecular weight of the outermost polymer of the thermoplastic resin component layer (II) is 30,000 or less by GPC method. (5) The total mass ratio of the rubber component layer (I) to the thermoplastic resin component layer (II) [(I) / (II)] is 30 / 70 to 90 / 10. (6) The average particle diameter of the multilayer polymer particles (B) is 150 nm or less. The conditions are met, The mass ratio ((A) / (B)) of thermoplastic polyurethane elastomer (A) to multilayer polymer particles (B) is 70 / 30 or more and 95 / 5 or less. Shear rate of thermoplastic polyurethane elastomer (A) 121.6 sec －１ The melt viscosity η(A) of the polyurethane resin composition is at a shear rate of 121.6 sec. －１ The melt viscosity ratio ηr to the melt viscosity η satisfies the following relationship: Melt viscosity ratio ηr(180°C): η(A) / η > 1.0 Melt viscosity ratio ηr(200°C): η(A) / η ≤ 1.0 The thermoplastic polyurethane elastomer (A) is characterized in that its melt viscosity η(A) is 300 to 1,000 Pa·s when measured at 200°C, and 500 to 10,000 Pa·s when measured at 180°C. Polyurethane resin composition.

2. The polyurethane resin composition according to claim 1, characterized in that the polyurethane resin composition comprises 60 to 99 parts by mass of thermoplastic polyurethane elastomer (A) and 1 to 40 parts by mass of multilayer polymer particles (B).

3. The polyurethane resin composition according to claim 1 or 2, wherein the Shore A hardness measured by a method compliant with JIS K 6253 is 60 to 95.

4. A polyurethane resin composition according to any one of claims 1 to 3, which is a resin composition for extrusion molding.

5. A polyurethane resin composition according to any one of claims 1 to 3, which is a resin composition for film extrusion.

6. A method for producing a polyurethane resin composition according to any one of claims 1 to 3, wherein the multilayer polymer particles (B) Polymerization reaction step (S1) to form at least one rubber component layer (I) inside by copolymerization of a monomer mixture (i) consisting of 50 to 99.99% by mass of an acrylic acid ester, 49.99 to 0% by mass of another monofunctional monomer copolymerizable with the acrylic acid ester, and 0.01 to 10% by mass of a polyfunctional monomer; and Polymerization reaction step (S2) to form at least one thermoplastic resin component layer (II) at least on the outermost surface by polymerization of a monomer (ii) consisting of 40 to 100% by mass of a methacrylic acid ester and 60 to 0% by mass of another monomer copolymerizable with the methacrylic acid ester; Including manufacturing by, In the polymerization reaction step (S2), the number-average molecular weight of the constituent copolymer of at least the outermost thermoplastic resin component layer (II) is set to 30,000 or less by the GPC method. The mass ratio ((i) / (ii)) of the total amount of monomer mixture (i) to the total amount of monomer mixture (ii) is set to be within the range of 30 / 70 to 90 / 10. A manufacturing method in which the average particle size of the manufactured multilayer polymer particles (B) is 150 nm or less.

7. A method for producing an extruded article comprising a polyurethane resin composition according to any one of claims 1 to 3, characterized in that the polyurethane resin composition is extruded at a temperature at which the molten resin temperature in the die portion during extrusion is 200°C or higher.

8. A method for producing a film comprising a polyurethane resin composition according to any one of claims 1 to 3, characterized in that the polyurethane resin composition is extruded as a film at a temperature at which the molten resin temperature in the T-die portion during extrusion is 200°C or higher.

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