Plasticizer and thermoplastic resin composition

Abstract

To provide a plasticizer capable of obtaining a thermoplastic resin composition excellent in flexibility, cold resistance and heat resistance.SOLUTION: The plasticizer contains a (meth) acrylic polymer having a weight average molecular weight of 3,000 or less. The (meth) acrylic polymer includes a structural unit (U1) derived from an alkyl (meth) acrylate and a structural unit (U2) having a cyclic ether group having 3 to 5 ring atoms, and has an SP value of 9.30 or more and a glass-transition temperature of - 75 °C. or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a plasticizer and a thermoplastic resin composition. [Background technology]

[0002] Plasticizers are commonly used to soften thermoplastic resins such as vinyl chloride resins and ABS resins. Furthermore, among articles manufactured using thermoplastic resins, sheets and films intended for outdoor use often require excellent flexibility, heat resistance, and weather resistance. However, resin compositions containing phthalate esters, trimellitate esters, polyesters, and polyethers, which have been widely used as plasticizers, together with thermoplastic resins, have shown insufficient weather resistance and heat resistance. Specifically, when low-molecular-weight compounds such as phthalate esters and trimellitate esters are used as plasticizers, the plasticizers are easily released from the resin composition over time, which can lead to a loss of flexibility and the resulting cracks in the product. Furthermore, when high-molecular-weight compounds such as polyesters and polyethers are used as plasticizers, the plasticizers in the resin composition decompose over time, resulting in the release of decomposition products from the resin composition, which can prevent the resin composition from maintaining its weather resistance over a long period of time.

[0003] Therefore, it has been proposed to use a relatively low molecular weight (meth)acrylic polymer as a plasticizer (see, for example, Patent Document 1 and Patent Document 2). Patent Document 1 discloses the use of an acrylic polymer obtained by polymerizing monomers at a temperature of 180 to 350°C for 5 to 60 minutes as a plasticizer. Patent Document 2 discloses the use of a copolymer of an alkoxyalkyl (meth)acrylate and another monomer as a plasticizer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2001 / 83619 [Patent Document 2] International Publication No. 2002 / 100943 Summary of the Invention [Problem to be solved by the invention]

[0005] It has been confirmed that resin products using the (meth)acrylic polymers disclosed in Patent Documents 1 and 2 as plasticizers are brittle in low-temperature environments (e.g., −20°C) and are prone to breakage when subjected to impact in low-temperature environments. Furthermore, the inventors have found that, when stored for a long period of time in a high-temperature environment, for example, at 100°C, the resin products harden and are prone to deterioration in mechanical properties, as well as to change in color (browning or blackening).

[0006] The present invention has been made in view of the above circumstances, and one object of the present invention is to provide a plasticizer with which a thermoplastic resin composition having excellent flexibility, cold resistance, and heat resistance can be obtained. [Means for solving the problem]

[0007] According to the present invention, the following plasticizer and thermoplastic resin composition are provided.

[0008] [1] A plasticizer containing a (meth)acrylic polymer having a weight-average molecular weight of 3,000 or less, the (meth)acrylic polymer containing a structural unit (U1) derived from a (meth)acrylic acid alkyl ester and a structural unit (U2) having a cyclic ether group having 3 to 5 ring members, and having an SP value of 9.30 or more and a glass transition temperature of -75°C or less. [2] The plasticizer according to [1], wherein the (meth)acrylic polymer has a cyclic ether group content of 0.01 to 0.50 meq / g. [3] The plasticizer according to [1] or [2], wherein the (meth)acrylic polymer has a carbon-carbon double bond content of 0.01 to 1.20 meq / g. [4] The plasticizer according to any one of [1] to [3], wherein the content of the structural unit (U1) is 90 mass% or more based on the total amount of structural units derived from monomers constituting the (meth)acrylic polymer. [5] The plasticizer according to any one of [1] to [4], which is used for plasticizing vinyl chloride resins. [6] A thermoplastic resin composition containing the plasticizer according to any one of [1] to [5] and a thermoplastic resin. [Effects of the Invention]

[0009] The plasticizer of the present invention makes it possible to obtain a thermoplastic resin composition having excellent flexibility, cold resistance, and heat resistance. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below. In this specification, "(meth)acrylic" means acrylic and / or methacrylic, "(meth)acrylate" means acrylate and / or methacrylate, and "(meth)acrylo" means acrylo and / or methacrylo.

[0011] <Plasticizer> The plasticizer of the present invention contains a (meth)acrylic polymer (hereinafter also referred to as "(meth)acrylic polymer (P)") having a weight-average molecular weight of 3,000 or less. The (meth)acrylic polymer (P) is mainly composed of structural units derived from a (meth)acrylic acid alkyl ester. The (meth)acrylic polymer (P) also contains structural units having a cyclic ether structure having 3 to 5 ring members, in addition to the structural units derived from a (meth)acrylic acid alkyl ester. Hereinafter, the physical properties of the (meth)acrylic polymer (P) will first be described, followed by a description of the structural units contained in the (meth)acrylic polymer (P).

[0012] <Physical Properties of (Meth)acrylic Polymer (P)> (Molecular weight characteristics) The weight-average molecular weight of the (meth)acrylic polymer (P) is 3,000 or less. If the weight-average molecular weight (Mw) of the (meth)acrylic polymer (P) exceeds 3,000, the cold resistance of the thermoplastic resin composition containing the thermoplastic resin and the (meth)acrylic polymer (P) may not be sufficiently ensured. From the viewpoint of obtaining a resin composition with sufficiently high cold resistance, the Mw of the (meth)acrylic polymer (P) is preferably 2,500 or less, more preferably 2,000 or less, even more preferably 1,800 or less, and even more preferably 1,650 or less. There are no particular restrictions on the lower limit of the Mw of the (meth)acrylic polymer (P), but from the viewpoint of suppressing volatilization of the plasticizer during thermoforming of the thermoplastic resin and from the viewpoint of obtaining a resin composition with good weather resistance, it is preferably 500 or more, more preferably 600 or more, and even more preferably 1,000 or more.

[0013] The number average molecular weight (Mn) of the (meth)acrylic polymer (P) is preferably 2,500 or less, more preferably 2,000 or less, even more preferably 1,800 or less, and even more preferably 1,500 or less. The lower limit of Mn of the (meth)acrylic polymer (P) is, for example, 500 or more, preferably 600 or more, and more preferably 750 or more. In this specification, the molecular weight of the polymer is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0014] The molecular weight distribution (Mw / Mn) of the (meth)acrylic polymer (P), which is the ratio of Mw to Mn, is preferably 1.60 or less, more preferably 1.50 or less, from the viewpoint of enhancing the effect of plasticizing the thermoplastic resin. The lower limit of Mw / Mn of the (meth)acrylic polymer (P) is not particularly limited, and can be 1.0 or more.

[0015] (SP value) The (meth)acrylic polymer (P) has an SP value, which is a solubility parameter, of 9.30 or more. If the SP value of the (meth)acrylic polymer (P) is less than 9.30, the compatibility of the (meth)acrylic polymer (P) with the thermoplastic resin will be poor. From the viewpoints of improving the compatibility of the (meth)acrylic polymer (P) with the thermoplastic resin, imparting sufficient flexibility to the thermoplastic resin composition, and improving the heat resistance and cold resistance of the thermoplastic resin composition, the SP value of the (meth)acrylic polymer (P) is preferably 9.32 or more, more preferably 9.35 or more, even more preferably 9.38 or more, and even more preferably 9.50 or more. There are no particular restrictions on the upper limit of the SP value of the (meth)acrylic polymer (P), but from the viewpoint of improving compatibility with the thermoplastic resin, it is, for example, 11.0 or less, or may be 10.0 or less, or may be 9.80 or less.

[0016] In this specification, the SP value of a polymer is a value calculated by the Fedors method (unit: [cal / cm 3 ] 1 / 2 Specifically, the SP value of a polymer can be calculated by the calculation method described in "Polymer Engineering and Science" by RF Edors, 14(2), 147 (1974).

[0017] (glass transition temperature) The glass transition temperature (Tg) of the (meth)acrylic polymer (P) is −75° C. or lower. If the glass transition temperature of the (meth)acrylic polymer (P) is higher than −75° C., when a thermoplastic resin composition is produced by blending the (meth)acrylic polymer (P), the cold resistance of the thermoplastic resin composition tends to be insufficient. From the viewpoint of obtaining a thermoplastic resin composition having excellent heat resistance in addition to cold resistance, the Tg of the (meth)acrylic polymer (P) is preferably −78° C. or lower, more preferably −79° C. or lower, and even more preferably −80° C. or lower. The lower limit of the Tg of the (meth)acrylic polymer (P) is not particularly limited, but is, for example, −90° C. or higher from the viewpoint of easy availability of raw materials. In this specification, the Tg of the polymer is a value obtained by a differential scanning calorimeter (DSC) at a heating rate of 10° C. / min in a nitrogen atmosphere. The measurement conditions are as described in the Examples below.

[0018] (carbon-carbon double bond content) In the (meth)acrylic polymer (P), at least a part of the polymers constituting the (meth)acrylic polymer (P) as a molecular aggregate preferably have a carbon-carbon double bond at the end. By having a carbon-carbon double bond at the molecular end of at least a part of the (meth)acrylic polymer (P), the compatibility of the (meth)acrylic polymer (P) with thermoplastic resins can be further improved.

[0019] From the viewpoint of sufficiently enhancing the effect of improving the compatibility between the (meth)acrylic polymer (P) and the thermoplastic resin, the content of carbon-carbon double bonds in the (meth)acrylic polymer (P) (hereinafter also referred to as "double bond concentration") is preferably 0.01 meq / g or more, more preferably 0.02 meq / g or more. With regard to the upper limit of the double bond concentration, from the viewpoint of ensuring the heat resistance and cold resistance of the thermoplastic resin composition blended with the plasticizer, it is preferably 1.20 meq / g or less, more preferably 0.80 meq / g or less, even more preferably 0.50 meq / g or less, and even more preferably 0.40 meq / g or less. In this specification, the double bond concentration of the polymer is 1It is a value calculated from the amount of double bonds in the polymer determined by H-NMR measurement and the composition of the polymer. Details of the measurement method follow the method described in the Examples below.

[0020] A preferred range of the double bond concentration of the (meth)acrylic polymer (P) can be set by appropriately combining the above-mentioned preferred upper and lower limits of the double bond concentration of the (meth)acrylic polymer (P). Specifically, the double bond concentration of the (meth)acrylic polymer (P) is preferably in the range of 0.01 to 1.20 meq / g, more preferably 0.01 to 0.80 meq / g, even more preferably 0.01 to 0.50 meq / g, still more preferably 0.01 to 0.40 meq / g, and even more preferably 0.02 to 0.40 meq / g.

[0021] (viscosity) The viscosity of the (meth)acrylic polymer (P) is preferably 1,000 mPa·s or less, more preferably 600 mPa·s or less, and even more preferably 400 mPa·s or less, from the viewpoint of enhancing the plasticizing effect of the (meth)acrylic polymer (P). There are no particular restrictions on the lower limit of the viscosity of the (meth)acrylic polymer (P), but from the viewpoint of suppressing bleed-out of the (meth)acrylic polymer (P) in a thermoplastic resin composition containing the (meth)acrylic polymer (P), it is preferably 80 mPa·s or more, and more preferably 90 mPa·s or more. In this specification, the viscosity of the polymer is a value measured at 25°C using an E-type viscometer.

[0022] (Cyclic Ether Group Value) The (meth)acrylic polymer (P) contains a structural unit having a cyclic ether group having 3 to 5 ring members. By virtue of the (meth)acrylic polymer (P) having a cyclic ether group having 3 to 5 ring members, the flexibility of a thermoplastic resin composition containing the (meth)acrylic polymer (P) can be improved in a well-balanced manner in terms of heat resistance and cold resistance while maintaining the flexibility. From the viewpoint of improving the flexibility, heat resistance, and cold resistance of the thermoplastic resin composition, the content of the cyclic ether group having 3 to 5 ring members in the (meth)acrylic polymer (P) (hereinafter also referred to as the "cyclic ether group value") is preferably 0.01 meq / g or more, more preferably 0.02 meq / g or more. From the viewpoint of ensuring the flexibility of a thermoplastic resin composition containing the (meth)acrylic polymer (P), the upper limit of the cyclic ether group value is preferably 0.50 meq / g or less, more preferably 0.40 meq / g or less, even more preferably 0.30 meq / g or less, and even more preferably 0.25 meq / g or less. In this specification, the cyclic ether group value of the polymer is a value measured in accordance with ASTM D-1652.

[0023] The preferred range of the cyclic ether group value of the (meth)acrylic polymer (P) can be set by appropriately combining the above-mentioned preferred upper and lower limits of the cyclic ether group value of the (meth)acrylic polymer (P). Specifically, the range of the cyclic ether group value of the (meth)acrylic polymer (P) is preferably 0.01 to 0.50 meq / g, more preferably 0.01 to 0.40 meq / g, and even more preferably 0.01 to 0.30 meq / g. The range is more preferably 0.02 to 0.30 meq / g, and even more preferably 0.02 to 0.25 meq / g.

[0024] It is believed that the introduction of a cyclic ether group into a (meth)acrylic polymer with a relatively low molecular weight increases compatibility with the thermoplastic resin, making it less likely for the (meth)acrylic polymer (P) to be released from the resin composition, and that the cyclic ether group in the (meth)acrylic polymer (P) functions as a radical scavenger, thereby suppressing the formation of structures that cause discoloration in the thermoplastic resin. These factors combined together suggest that a plasticizer containing the (meth)acrylic polymer (P) can increase the flexibility of the thermoplastic resin composition while suppressing color change in high-temperature environments and maintaining good flexibility of the thermoplastic resin composition even in low-temperature environments. In particular, when a carbon-carbon double bond is introduced into the molecular terminal of the (meth)acrylic polymer (P), the carbon-carbon double bond at the molecular terminal efficiently functions as a radical scavenger, further suppressing the formation of structures that cause discoloration in the thermoplastic resin. However, these are merely speculations and do not limit the present invention in any way.

[0025] <Structural Unit of (Meth)acrylic Polymer (P)> Next, the structural units contained in the (meth)acrylic polymer (P) will be described. Hereinafter, a structural unit derived from a (meth)acrylic acid alkyl ester will also be referred to as a "structural unit (U1)," and a structural unit having a cyclic ether group having 3 to 5 ring members will also be referred to as a "structural unit (U2)."

[0026] Structural unit (U1) The (meth)acrylic acid alkyl ester is represented by the following general formula (1): CH2=CR 1 -COO-R 2 (1) where R 1 is a hydrogen atom or a methyl group. 2 The (meth)acrylic acid alkyl ester constituting the structural unit (U1) is an ester group portion (i.e., —COO—R in the above general formula (1)). 2) has a linear or branched alkyl group having 1 to 30 carbon atoms. Specific examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, stearyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate.

[0027] From the viewpoint of sufficiently enhancing the plasticizing effect of the (meth)acrylic polymer (P) and improving the heat resistance and cold resistance of the thermoplastic resin composition in a balanced manner, the content of the structural unit (U1) in the (meth)acrylic polymer (P) is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 85% by mass or more, still more preferably 90% by mass or more, and even more preferably 95% by mass or more, based on the total amount of structural units derived from the monomers constituting the (meth)acrylic polymer (P). Note that, as the (meth)acrylic acid alkyl ester constituting the (meth)acrylic polymer (P), one type may be used alone, or two or more types may be used in combination.

[0028] From the viewpoint of improving the cold resistance of the thermoplastic resin composition, it is preferable that the (meth)acrylic acid alkyl ester constituting the (meth)acrylic polymer (P) contains a (meth)acrylic acid alkyl ester having an alkyl group having 3 or more carbon atoms.

[0029] In the (meth)acrylic polymer (P), the content of structural units derived from a (meth)acrylic acid alkyl ester having an alkyl group having 3 or more carbon atoms is, from the viewpoint of enhancing the effect of improving cold resistance, preferably 10% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, still more preferably 50% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, and even more preferably 90% by mass or more, relative to the total amount of structural units derived from monomers constituting the (meth)acrylic polymer (P).

[0030] As the (meth)acrylic acid alkyl ester constituting the structural unit (U1), among the above, a (meth)acrylic acid alkyl ester having 3 to 18 carbon atoms can be preferably used, since it can provide a thermoplastic resin composition having a well-balanced improved cold resistance and heat resistance. Among these, in particular, a (meth)acrylic acid alkyl ester having 3 to 16 carbon atoms is more preferred, and a (meth)acrylic acid alkyl ester having 4 to 16 carbon atoms is even more preferred.

[0031] An acrylic acid alkyl ester is preferably used as the monomer constituting the structural unit (U1) in that it can sufficiently lower the glass transition temperature of the (meth)acrylic polymer (P). In the (meth)acrylic polymer (P), the content of structural units derived from an acrylic acid alkyl ester is preferably 40 mass% or more, more preferably 50 mass% or more, even more preferably 60 mass% or more, even more preferably 70 mass% or more, still more preferably 80 mass% or more, and even more preferably 90 mass% or more, based on the total amount of structural units derived from the monomers constituting the (meth)acrylic polymer (P).

[0032] In order to sufficiently lower the glass transition temperature of the (meth)acrylic polymer (P), an alkyl acrylate ester having an alkyl group containing 6 to 18 carbon atoms is preferably used as at least a portion of the monomers constituting the structural unit (U1). The amount used can be appropriately determined depending on the desired glass transition temperature of the polymer. Specifically, in the (meth)acrylic polymer (P), the content of structural units derived from an alkyl acrylate ester having an alkyl group containing 6 to 18 carbon atoms is, for example, 5% by mass or more, preferably 10% by mass or more, and more preferably 20% by mass or more, based on the total amount of structural units derived from the monomers constituting the (meth)acrylic polymer (P). Furthermore, from the viewpoint of ensuring compatibility with thermoplastic resins, the content of structural units derived from an alkyl acrylate ester having an alkyl group containing 6 to 18 carbon atoms is preferably 90% by mass or less, more preferably 80% by mass or less, based on the total amount of structural units derived from the monomers constituting the (meth)acrylic polymer (P).

[0033] Structural unit (U2) Examples of the monomer having a cyclic ether group having 3 to 5 ring members that constitutes the structural unit (U2) include a compound having an oxiranyl group, a compound having an oxetanyl group, and a compound having a tetrahydrofuranyl group. The cyclic ether group may have a substituent (e.g., an alkyl group having 1 to 4 carbon atoms) on the ring portion.

[0034] Specific examples of the monomer that constitutes the structural unit (U2) include glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, 3,4-epoxycyclohexylmethyl (meth)acrylate, (3-ethyloxetan-3-yl)methyl (meth)acrylate, and tetrahydrofurfuryl (meth)acrylate.

[0035] Of the above, a (meth)acrylic monomer having an oxiranyl group is preferably used as the monomer constituting the structural unit (U2) in terms of increasing the flexibility of the thermoplastic resin composition and cost. The monomer having a cyclic ether group having 3 to 5 ring members constituting the (meth)acrylic polymer (P) may be one type or two or more types.

[0036] The content of the structural unit (U2) in the (meth)acrylic polymer (P) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, based on the total amount of structural units derived from the monomers constituting the (meth)acrylic polymer (P), in order to sufficiently suppress deterioration of the mechanical properties of the thermoplastic resin composition even when the resin composition is stored in a high-temperature environment (e.g., 100°C) and a low-temperature environment (e.g., -20°C or lower) and to effectively suppress color changes (browning or blackening) under high-temperature environments. The upper limit of the content of the structural unit (U2) in the (meth)acrylic polymer (P) is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on the total amount of structural units derived from the monomers constituting the (meth)acrylic polymer (P), in order to ensure compatibility of the (meth)acrylic polymer (P) with the thermoplastic resin and increase the flexibility of the thermoplastic resin composition.

[0037] (Other monomers) The (meth)acrylic polymer (P) may be composed only of the structural unit (U1) and the structural unit (U2). The (meth)acrylic polymer (P) may further contain structural units derived from monomers other than the (meth)acrylic acid alkyl ester and the monomer having a cyclic ether group having 3 to 5 ring members (hereinafter also referred to as "other monomers"), for the purpose of adjusting the glass transition temperature or SP value of the polymer, within a range that does not impair the effects of the present invention.

[0038] The other monomer is not particularly limited as long as it is a monomer copolymerizable with the (meth)acrylic acid alkyl ester and the monomer having a cyclic ether group having 3 to 5 ring members. Examples of the other monomer include unsaturated carboxylic acids, unsaturated acid anhydrides, aliphatic cyclic (meth)acrylic acid esters, aromatic (meth)acrylic acid esters, (meth)acrylic acid alkoxyalkyl esters, (meth)acrylic acid hydroxyalkyl esters, polyalkylene glycol mono(meth)acrylates, halogen-containing vinyl compounds, vinyl ester compounds, vinyl ether compounds, amino group-containing vinyl compounds, amide group-containing vinyl compounds, nitrile group-containing vinyl compounds, aromatic vinyl compounds, and maleimide compounds. One type of the other monomer may be used alone, or two or more types may be used in combination.

[0039] Specific examples of these include unsaturated carboxylic acids such as (meth)acrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, citraconic acid, cinnamic acid, succinic acid monohydroxyethyl (meth)acrylate, ω-carboxy-caprolactone mono(meth)acrylate, β-carboxyethyl (meth)acrylate, 4-carboxystyrene, etc., and unsaturated acid anhydrides such as maleic anhydride, itaconic anhydride, citraconic anhydride, etc.

[0040] Examples of the aliphatic cyclic esters of (meth)acrylic acid include cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentanyl (meth)acrylate. Examples of the aromatic esters of (meth)acrylic acid include phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxymethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, and 3-phenoxypropyl (meth)acrylate.

[0041] Examples of the alkoxyalkyl (meth)acrylate include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, n-propoxyethyl (meth)acrylate, n-butoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, n-propoxypropyl (meth)acrylate, n-butoxypropyl (meth)acrylate, methoxybutyl (meth)acrylate, ethoxybutyl (meth)acrylate, n-propoxybutyl (meth)acrylate, and n-butoxybutyl (meth)acrylate.

[0042] Examples of the hydroxyalkyl (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Examples of the polyalkylene glycol mono(meth)acrylate include polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and polyethylene glycol-polypropylene glycol mono(meth)acrylate.

[0043] Examples of halogen-containing vinyl compounds include vinyl chloride, vinylidene chloride, vinyl fluoride, and vinylidene fluoride. Examples of vinyl ester compounds include vinyl acetate and vinyl propionate. Examples of vinyl ether compounds include methyl vinyl ether, ethyl vinyl ether, and butyl vinyl ether.

[0044] Examples of the amino group-containing vinyl compound include dimethylaminomethyl (meth)acrylate, diethylaminomethyl (meth)acrylate, 2-dimethylaminoethyl (meth)acrylate, 2-diethylaminoethyl (meth)acrylate, 2-(di-n-propylamino)ethyl (meth)acrylate, 2-dimethylaminopropyl (meth)acrylate, 2-diethylaminopropyl (meth)acrylate, 2-(di-n-propylamino)propyl (meth)acrylate, 3-dimethylaminopropyl (meth)acrylate, 3-diethylaminopropyl (meth)acrylate, and 3-(di-n-propylamino)propyl (meth)acrylate.

[0045] Examples of the amide group-containing vinyl compound include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, and N-methylol(meth)acrylamide.

[0046] Examples of the nitrile group-containing vinyl compound include cyanomethyl (meth)acrylate, 1-cyanoethyl (meth)acrylate, 2-cyanoethyl (meth)acrylate, 1-cyanopropyl (meth)acrylate, 2-cyanopropyl (meth)acrylate, 3-cyanopropyl (meth)acrylate, 4-cyanobutyl (meth)acrylate, 6-cyanohexyl (meth)acrylate, 2-ethyl-6-cyanohexyl (meth)acrylate, 8-cyanooctyl (meth)acrylate, (meth)acrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile, α-chloroacrylonitrile, and α-fluoroacrylonitrile.

[0047] Examples of aromatic vinyl compounds include styrene, α-methylstyrene, β-methylstyrene, vinylxylene, methylstyrene, ethylstyrene, butylstyrene, methoxystyrene, hydroxystyrene, isopropenylphenol, vinylbenzoic acid, and vinylnaphthalene.

[0048] Examples of the maleimide compound include maleimide and N-substituted maleimide compounds. Examples of the N-substituted maleimide compound include N-alkyl-substituted maleimides such as N-methylmaleimide, N-ethylmaleimide, Nn-propylmaleimide, N-isopropylmaleimide, Nn-butylmaleimide, N-isobutylmaleimide, and N-tert-butylmaleimide; N-cycloalkyl-substituted maleimides such as N-cyclopentylmaleimide and N-cyclohexylmaleimide; N-aralkyl-substituted maleimides such as N-benzylmaleimide; and N-aryl-substituted maleimides such as N-phenylmaleimide, N-(4-hydroxyphenyl)maleimide, N-(4-acetylphenyl)maleimide, and N-(4-methoxyphenyl)maleimide.

[0049] From the viewpoint of fully exerting the plasticizing effect, it is preferable that the (meth)acrylic polymer (P) is substantially free of structural units having a carboxyl group. Specifically, the content of structural units having a carboxyl group in the (meth)acrylic polymer (P) is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, and still more preferably 0.5% by mass or less, based on the total structural units of the (meth)acrylic polymer (P).

[0050] <Constituents of plasticizers> The plasticizer of the present invention may be composed of a (meth)acrylic polymer (P), or may further contain a component different from the (meth)acrylic polymer (P) (hereinafter also referred to as "other component"). In the plasticizer of the present invention, the content of the (meth)acrylic polymer (P) is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more, based on the total amount of the plasticizer. The (meth)acrylic polymer (P) blended in the plasticizer may be one type or two or more types.

[0051] Examples of other components to be blended into the plasticizer include an oligomer of a (meth)acrylic polymer different from the (meth)acrylic polymer (P) that exhibits a plasticizing effect; a known ester-based or ether-based plasticizer; and the like. Only one type of other component may be used, or two or more types may be used. The content of the other components in the plasticizer of the present invention can be appropriately set within a range that does not impair the effects of the present invention.

[0052] <Plasticizer manufacturing method> The method for producing the above-mentioned plasticizer of the present invention is not particularly limited. The plasticizer of the present invention can be produced, for example, by a method including a step of obtaining a (meth)acrylic polymer (P) by polymerizing a monomer (hereinafter also referred to as a "polymerization step").

[0053] (Polymerization process) The polymerization method for producing the (meth)acrylic polymer (P) is not particularly limited. The (meth)acrylic polymer (P) can be obtained by polymerizing monomers using a known radical polymerization method such as solution polymerization, suspension polymerization, emulsion polymerization, or bulk polymerization. Among these, solution polymerization is preferred because it is easy to control the molecular weight and structure of the polymer.

[0054] In the case of solution polymerization, for example, a polymerization solvent and monomers are charged into a reactor, and a polymerization initiator is added to polymerize to obtain a target polymer. When carrying out polymerization, the method of charging each raw material including the monomer may be a batch-type initial lump-sum charging in which all raw materials are charged at once, a semi-continuous charging in which at least a portion of the raw materials are continuously fed into the reactor, or a continuous polymerization method in which all raw materials are continuously fed and at the same time the produced resin is continuously withdrawn from the reactor.

[0055] A preferred example of a polymerization method for obtaining the (meth)acrylic polymer (P) is a method (high-temperature continuous polymerization method) in which raw materials containing monomers, a polymerization solvent, and a polymerization initiator are supplied to a pressurized reactor at a constant supply rate, the raw materials are heated to a high temperature, and a polymer solution corresponding to the amount of raw materials supplied is withdrawn from the reactor. The high-temperature continuous polymerization method can produce a (meth)acrylic polymer with a low molecular weight and low viscosity. It can also easily produce a (meth)acrylic polymer having a terminal carbon-carbon double bond. Furthermore, when producing a (meth)acrylic polymer using the high-temperature continuous polymerization method, molecular weight control can be performed appropriately even when the amount of polymerization initiator or chain transfer agent used is reduced, and the amount of impurities in the plasticizer can be reduced. Therefore, when a mixture of the plasticizer of the present invention and a thermoplastic resin is molded, a resin product with excellent heat resistance, cold resistance, and high strength can be obtained.

[0056] As the polymerization solvent, an organic solvent can be preferably used. Examples of the organic solvent include cyclic ethers such as tetrahydrofuran and dioxane, chain ethers such as methyl orthoformate and trimethyl orthoacetate, aromatic hydrocarbons such as benzene, toluene and xylene, esters such as ethyl acetate and butyl acetate, ketones such as acetone, methyl ethyl ketone and cyclohexanone, and alcohols such as methanol, ethanol, normal propyl alcohol, isopropyl alcohol, normal butanol, secondary butyl alcohol, isobutyl alcohol, tertiary butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 3-methyl-1-butanol, 1-hexanol, 2-hexanol, 3-methyl-3-pentanol, 1-heptanol, 1-octanol, 2-ethylhexanol and 3-ethyl-3-hexanol.

[0057] The polymerization solvent preferably contains a primary alcohol. In the polymerization step for obtaining the (meth)acrylic polymer (P), monomers are polymerized in a solvent containing a primary alcohol. The (meth)acrylic polymer (P) obtained by the polymerization is mixed with a thermoplastic resin and molded to obtain a resin product with excellent cold resistance. From the viewpoint of enhancing the effect of improving cold resistance, the primary alcohol used in the polymerization solvent preferably has 4 to 8 carbon atoms, and from the viewpoint of easy availability of raw materials, normal butanol or 2-ethylhexanol is particularly preferred.

[0058] When polymerization is carried out using a primary alcohol as a polymerization solvent, the polymerization solvent may be a solvent consisting solely of a primary alcohol, or may be a mixed solvent of a primary alcohol and a polymerization solvent other than the primary alcohol (hereinafter also referred to as "other solvent"). Examples of other solvents include the organic solvents exemplified above. The amount of primary alcohol used is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, and even more preferably 50% by mass or more, based on the total amount of the polymerization solvent.

[0059] The amount of the polymerization solvent used is preferably 5 to 180 parts by mass, more preferably 10 to 150 parts by mass, per 100 parts by mass of the total amount of the monomers. The polymerization solvent may be used alone or in combination of two or more.

[0060] The polymerization initiator is not particularly limited, and known radical polymerization initiators such as organic peroxides, inorganic peroxides, and azo compounds can be used.

[0061] Specific examples of the polymerization initiator include organic peroxides such as di-tert-butyl peroxide, cyclohexanone peroxide, dibenzoyl peroxide, 3,3,5-trimethylcyclohexanone peroxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diisopropylbenzene peroxide, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, etc. Specific examples of inorganic peroxides include potassium persulfate, sodium persulfate, etc.

[0062] Examples of azo compounds include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 4,4'-azobis(4-cyanovaleric acid), 2-(tert-butylazo)-2-cyanopropane, 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(2-methylpropane), and dimethyl 2,2'-azobis(2-methylpropionate).

[0063] Furthermore, as the polymerization initiator, a redox type polymerization initiator comprising a known oxidizing agent and a known reducing agent may be used. Examples of redox type polymerization initiators include those using sodium sulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, ascorbic acid, ferrous sulfate, or the like as a reducing agent and potassium peroxodisulfate, hydrogen peroxide, tert-butyl hydroperoxide, or the like as an oxidizing agent. Furthermore, a known chain transfer agent can also be used in combination with the polymerization initiator. When producing the (meth)acrylic polymer (P), organic peroxides are preferably used as the polymerization initiator from the viewpoint of ease of controlling the molecular weight within the desired range.

[0064] In producing the (meth)acrylic polymer (P), the amount of the polymerization initiator used is, for example, 0.01 to 20 parts by mass, and preferably 0.05 to 15 parts by mass, relative to 100 parts by mass of the total amount of the monomers used in the polymerization.

[0065] From the viewpoints of controlling the molecular weight of the (meth)acrylic polymer (P) within the above range and suppressing coloration of the reaction solution due to the progress of the decomposition reaction, it is preferable to carry out the polymerization at a high temperature. Specifically, the polymerization temperature is preferably in the range of 180°C or higher and 350°C or lower. From the above viewpoints, the polymerization temperature is more preferably 200°C or higher, even more preferably 210°C or higher, and even more preferably 220°C or higher. The upper limit of the polymerization temperature is more preferably 330°C or lower, even more preferably 310°C or lower, and even more preferably 290°C or lower.

[0066] When polymerization is carried out by high-temperature continuous polymerization, the residence time of the raw materials is, for example, 2 to 60 minutes. The pressure during polymerization may be any pressure that can maintain the polymerization temperature.

[0067] Other embodiments of the synthesis method for the (meth)acrylic polymer (P) include, for example, the bulk polymerization methods described in JP-A-57-502171, JP-A-59-6207, and JP-A-60-215007. Furthermore, the product of bulk polymerization can be treated with a thin-film evaporator or the like to remove volatile components from the product, and further treated with a purification device such as that described in JP-A-2009-221265 to reduce the amount of low-molecular-weight components in the product. This allows for the production of a (meth)acrylic polymer (P) with higher purity.

[0068] If the polymer obtained by the polymerization contains sulfur atoms derived from sulfur-containing compounds such as mercaptans, this can cause a decrease in the weather resistance and tensile properties of the polymer. Therefore, it is preferable that the sulfur atom content in the (meth)acrylic polymer (P) be as low as possible. Specifically, the sulfur atom content in the (meth)acrylic polymer (P) is preferably 0 ppm or more and less than 1000 ppm, more preferably 0 ppm or more and less than 100 ppm, even more preferably 0 ppm or more and less than 10 ppm, and even more preferably 0 ppm or more and less than 1 ppm. In this specification, the "sulfur atom content" refers to the total amount of sulfur atoms contained in the polymer, and can be quantified by ICP atomic emission spectroscopy.

[0069] Phosphorus atoms derived from phosphorus compounds and the like also cause a decrease in the weather resistance and tensile properties of the polymer. Therefore, it is preferable that the phosphorus atom content in the (meth)acrylic polymer (P) be as low as possible. Specifically, the phosphorus atom content in the (meth)acrylic polymer (P) is preferably 0 ppm or more and less than 1000 ppm, more preferably 0 ppm or more and less than 100 ppm, even more preferably 0 ppm or more and less than 10 ppm, and even more preferably 0 ppm or more and less than 1 ppm. In this specification, the "phosphorus atom content" refers to the total amount of phosphorus atoms contained in the polymer, and can be quantified by ICP atomic emission spectroscopy.

[0070] Metal atoms derived from metal complex compounds, etc., can also cause a decrease in the weather resistance and tensile properties of the polymer and can also cause discoloration. Therefore, it is preferable that the metal atom content in the (meth)acrylic polymer (P) be as low as possible. Specifically, the metal atom content in the (meth)acrylic polymer (P) is preferably 0 ppm or more and less than 1000 ppm, more preferably 0 ppm or more and less than 100 ppm, even more preferably 0 ppm or more and less than 10 ppm, and even more preferably 0 ppm or more and less than 1 ppm. As used herein, the "metal atom content" refers to the total amount of metal atoms contained in the polymer, which can be quantified by ICP atomic emission spectroscopy. Note that metal complex compounds include metal complex compounds used as chain transfer agents, as well as metals present in the monomers, polymerization initiators, and polymerization solvents used in the production of the polymer, and metals introduced from the outside during production. Generally, commercially available monomers, polymerization initiators, and polymerization solvents are purified by distillation, recrystallization, or the like, and therefore the metal atom content of these reagents is less than 2 ppm. However, using unpurified raw materials is not preferred because the metal atom content in the raw materials will be high.

[0071] Residual volatile components remaining in the (meth)acrylic polymer (P), such as solvents, unreacted monomers, and decomposition products derived from the polymerization initiator, can also cause a decrease in the weather resistance and tensile properties of the polymer. These residual volatile components initially function as plasticizers, but over time, they gradually volatilize from the polymer, causing the polymer to lose its initial tensile properties and possibly producing an odor. Therefore, it is preferable that the amount of residual volatile components in the (meth)acrylic polymer (P) be as small as possible. Specifically, the amount of residual volatile components in the (meth)acrylic polymer (P) is preferably 0.0% or more and less than 2.0%, more preferably 0.0% or more and less than 1.5%, even more preferably 0.0% or more and less than 1.0%, even more preferably 0.0% or more and less than 0.8%, and even more preferably 0.0% or more and less than 0.5%. As used herein, the term "amount of residual volatile components" refers to the total amount of residual volatile components contained in the polymer, which can be quantified by gas chromatography.

[0072] The polymer obtained by the above polymerization may be subjected to isolation and / or purification treatment in order to remove low-molecular-weight compounds contained in the polymer. When the polymer is isolated and / or purified, these treatments can be carried out using known methods. For example, the isolation and purification of the polymer can be carried out by thin-film distillation, reprecipitation, or the like. The polymer obtained by the above polymerization may be used as a plasticizer as is, or may be used as a plasticizer after blending with other components as necessary.

[0073] ≪Thermoplastic resin composition≫ Next, the thermoplastic resin composition of the present invention will be described. The thermoplastic resin composition of the present invention contains the above-mentioned plasticizer of the present invention and a thermoplastic resin.

[0074] Examples of thermoplastic resins include polyolefins (e.g., polyethylene, polypropylene, etc.), vinyl chloride resins, polyvinyl acetate resins, polyurethane resins, polystyrene resins, AS resins (acrylonitrile-styrene copolymers), ABS resins (acrylonitrile-butadiene-styrene copolymers), AXS resins (styrene copolymers of rubber components other than acrylonitrile-butadiene), acrylic resins, polymethyl methacrylate resins, polyester resins, polyamide resins, etc. Of these, vinyl chloride resins are preferred.

[0075] Vinyl chloride resins are polymers containing structural units derived from vinyl chloride monomers. Vinyl chloride resins may be homopolymers of vinyl chloride monomers, or copolymers of vinyl chloride monomers and carbon-carbon unsaturated bond-containing monomers other than vinyl chloride monomers. Examples of vinyl chloride resins include polyvinyl chloride, ethylene-vinyl chloride copolymers, vinyl chloride-vinylidene chloride copolymers, vinyl chloride-acrylic copolymers, vinyl chloride-vinyl acetate copolymers, and chlorinated polyvinyl chloride. The thermoplastic resin composition of the present invention may contain only one type of thermoplastic resin, or two or more types of thermoplastic resins.

[0076] The content of the plasticizer in the thermoplastic resin composition can be appropriately set depending on the type of thermoplastic resin, the application of the thermoplastic resin composition, etc. From the viewpoint of easily adjusting the hardness of a resin product formed from the thermoplastic resin composition and obtaining a resin product in which plasticizer bleeding is suppressed, the content of the plasticizer in the thermoplastic resin composition is preferably 20 parts by mass or more and 150 parts by mass or less per 100 parts by mass of the thermoplastic resin. From the above viewpoints, the content of the plasticizer is more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and even more preferably 50 parts by mass or more per 100 parts by mass of the thermoplastic resin. Furthermore, the content of the plasticizer is more preferably 120 parts by mass or less, even more preferably 100 parts by mass or less, and even more preferably 90 parts by mass or less per 100 parts by mass of the thermoplastic resin.

[0077] The thermoplastic resin composition may further contain, in addition to the plasticizer and thermoplastic resin, a component different from the plasticizer and thermoplastic resin. Examples of such components include reinforcing agents (calcium carbonate, silica, zinc oxide, titanium oxide, etc.), lubricants (fatty acid esters, higher alcohols, glycerin esters, sorbitan esters, polyhydric alcohols, fatty acids, oil-based waxes, bisamides, etc.), antioxidants, UV absorbers, antioxidants, hydrochloric acid scavengers, flame retardants, antistatic agents, antifogging agents, antibacterial agents, preservatives, and colorants. The amounts of these additives may be appropriately determined depending on the respective components, as long as they do not impair the effects of the present invention. In one embodiment of the thermoplastic resin composition of the present invention containing a component different from the plasticizer and thermoplastic resin, the thermoplastic resin composition contains a plasticizer, a thermoplastic resin, and a lubricant. Another embodiment of the thermoplastic resin composition contains a plasticizer, a thermoplastic resin, a reinforcing agent, and a lubricant.

[0078] For example, when a reinforcing agent is blended into a thermoplastic resin composition, the content of the reinforcing agent is preferably 1 part by mass or more and 80 parts by mass or less, more preferably 2 parts by mass or more and 70 parts by mass or less, and even more preferably 5 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the thermoplastic resin.

[0079] When a lubricant is blended into the thermoplastic resin composition, the content of the lubricant is preferably 0.1 parts by mass or more and 12 parts by mass or less, more preferably 0.2 parts by mass or more and 10 parts by mass or less, and even more preferably 0.5 parts by mass or more and 5 parts by mass or less, per 100 parts by mass of the thermoplastic resin.

[0080] When an antioxidant is blended into the thermoplastic resin composition, the content of the antioxidant is preferably 0.1 parts by mass or more and 15 parts by mass or less, more preferably 0.2 parts by mass or more and 10 parts by mass or less, and even more preferably 0.5 parts by mass or more and 7 parts by mass or less, relative to 100 parts by mass of the thermoplastic resin.

[0081] A resin product can be obtained by kneading the above-mentioned thermoplastic resin composition, preferably at a temperature at which the thermoplastic resin in the thermoplastic resin composition melts, and forming or molding it into a desired shape using a known film-forming or molding method. The resin product thus obtained is plasticized using the (meth)acrylic polymer (P), so the plasticizer is less likely to volatilize during the resin product manufacturing process, and bleeding of the plasticizer in the resulting resin product can be suppressed. Furthermore, resin products obtained from the thermoplastic resin composition of the present invention are less likely to deteriorate in mechanical properties and have good cold resistance, even when stored for long periods in low-temperature environments (e.g., below -20°C). In addition, the resin product is less likely to harden or change in color (browning or blackening) even when stored for long periods in high-temperature environments, for example, above 100°C, and has excellent heat resistance.

[0082] Resin products formed using the thermoplastic resin composition of the present invention have excellent flexibility, heat resistance, and heat resistance, and are particularly suitable for use as sheets, films, and the like for outdoor use. [Example]

[0083] The present invention will be specifically described below based on examples. However, the present invention is not limited to these examples. In the following, "parts" and "%" mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

[0084] Details of the measurement methods and the like used for evaluating the polymer are as follows. <Molecular weight measurement> Using a gel permeation chromatograph (model name "HLC-8320", manufactured by Tosoh Corporation), the weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of polystyrene were obtained under the following conditions. ○Measurement conditions Column: 4 TSKgel SuperMultipore HZ-M columns manufactured by Tosoh Corporation Column temperature: 40 °C Eluent: Tetrahydrofuran Detector: RI

[0085] <Viscosity measurement> Using a TVE-20H type viscometer (salt water / plate method, manufactured by Toki Sangyo Co., Ltd.), the viscosity of the polymer was measured with an E-type viscometer under the following conditions. ○Measurement conditions Cone shape: Angle 1°34′, radius 24 mm Temperature: 25 °C ± 0.5 °C

[0086] <SP value> The SP value (unit: [cal / cm 3 1 / 2 ) was calculated by the Fedors method. <Measurement of glass transition temperature (Tg)> The Tg of the polymer was measured with a differential scanning calorimeter (DSC) under the following conditions. DSC: DSC 214 Polyma manufactured by NETZSCH Temperature rising rate: 10 °C / min Measurement atmosphere: Nitrogen

[0087] <Quantification of double bond amount> 1 ​By H-NMR measurement, the amount of double bonds per unit mass of the polymer (i.e., double bond concentration) was calculated from the ratio of the integral value of the signal derived from hydrogen bonded to the double bond near 5.5 ppm to the integral value of the signal derived from hydrogen bonded to the carbon adjacent to the ester group at 3.0 to 4.5 ppm, and the composition of the polymer.

[0088] <Epoxy value measurement> The epoxy value was measured as a cyclic ether group value in accordance with ASTM D-1652. <Number of epoxy groups per molecule (average value)> When the total amount of monomers used in the production of each polymer was 100 parts by mass and x parts by mass of epoxy group-containing monomer was contained therein, the number of epoxy groups per polymer molecule, Qep (average value), was calculated using the following formula, where Mn represents the number average molecular weight of the polymer. Qep=x / [(molecular weight of epoxy group-containing monomer × 100) / Mn]

[0089] 1. Synthesis of (meth)acrylic polymers [Production Example 1] Production of Polymer P-1 The temperature of a 1000 mL oil-jacketed pressurized stirred tank reactor was maintained at 250°C. Next, while maintaining a constant reactor pressure, a monomer mixture containing 64 parts n-butyl acrylate (hereinafter referred to as "BA"), 35 parts 2-ethylhexyl acrylate (hereinafter referred to as "HA"), 1 part glycidyl methacrylate (hereinafter referred to as "GMA"), 40 parts normal butanol (hereinafter referred to as "n-BuOH"), and 2 parts di-t-butyl peroxide (NOF Corp., trade name "Perbutyl D", hereinafter referred to as "DTBP") as a polymerization initiator was continuously fed from a raw material tank to the reactor at a constant feed rate (48 g / min). The polymerization reaction proceeded with a residence time of 12 minutes. Concurrently, a reaction solution equivalent to the amount of monomer mixture fed was continuously withdrawn from the reactor outlet and recovered. Immediately after the start of the reaction, the reaction temperature temporarily dropped, but a temperature increase due to the heat of polymerization was observed. Therefore, the reaction temperature was maintained at 276°C to 278°C (listed as 277°C in Table 1) by controlling the temperature of the oil jacket. The point at which the liquid temperature in the reactor stabilized after the start of the monomer mixture supply was defined as the start point for collecting the reaction liquid, and the reaction was carried out for 25 minutes from the start point. In the reaction step, the amount of the monomer mixture supplied was 1.2 kg, and the amount of the reaction liquid recovered was 1.2 kg. The mixed liquid of polymer, solvent, and unreacted monomer coming out of the reactor was continuously introduced into a thin-film evaporator to separate volatile components such as unreacted monomer, and 0.73 kg of polymer P-1 was obtained.

[0090] [Production Examples 2 to 10, Comparative Production Examples 1 to 3] Polymers P-2 to P-13, which are (meth)acrylic polymers, were obtained in the same manner as in Production Example 1, except that the types and amounts of raw materials used were changed as shown in Table 1. In Table 1, "TDA" represents tetradecyl acrylate, "IPA" represents isopropyl alcohol, and "MEK" represents methyl ethyl ketone. The monomer composition ratios of polymers P-1 to P-13 were the same as the monomer charging ratios.

[0091] [Table 1]

[0092] 2. Production of thermoplastic resin composition (1) The (meth)acrylic polymers obtained in the above Production Examples and Comparative Production Examples were used as plasticizers to produce the following thermoplastic resin compositions. [Example 1] 100 parts of vinyl chloride resin (manufactured by Shin-Dai-Ichi Vinyl Corporation, trade name "ZEST 1300Z"), 70 parts of polymer P-1, 1.2 parts of calcium stearate, 0.3 parts of zinc stearate, and 2 parts of an antioxidant (manufactured by BASF, trade name "Tinuvin B75") were mixed and kneaded at 160°C in a Laboplastomill to obtain thermoplastic resin composition R-1.

[0093] [Examples 2 to 10, Comparative Examples 1 to 4] Thermoplastic resin compositions R-2 to R-14 were obtained in the same manner as in Example 1, except that the types and amounts of plasticizers used were as shown in Table 2. The epoxidized soybean oil used in Table 2 was "O-130P" manufactured by ADEKA Corporation (the same applies to Table 3).

[0094] 3. Evaluation (1) The thermoplastic resin compositions R-1 to R-14 obtained in the above examples and comparative examples were evaluated as follows. The evaluation results are shown in Table 2. <compatibility> In the production of the above thermoplastic resin composition, the state of the resin after kneading (degree of cohesion) was observed, and the compatibility was evaluated according to the following criteria. ○: Good compatibility (resin is well-formed and transparent) △: Compatible (resin is solid but opaque) ×: Poor compatibility (resin is not cohesive and falls apart overall)

[0095] <Tensile properties> Room temperature tensile test The thermoplastic resin composition was press-molded at 190°C to obtain a No. 3 dumbbell test piece (thickness: 1 mm). After conditioning the test piece at 23°C and 50% RH for 24 hours, the breaking stress (MPa) and breaking elongation (%) were measured at a tension speed of 200 mm / min using a tensile tester (Autograph AGS-J, manufactured by Shimadzu Corporation). Low temperature tensile test The No. 3 dumbbell test pieces prepared in the same manner as the room temperature tensile test were cooled in a thermostatic chamber at -20°C for 1 hour, and then immediately measured for breaking stress (MPa) and breaking elongation (%) at a tensile speed of 200 mm / min using a tensile testing machine.

[0096] <Heat resistance test> Tensile properties No. 3 dumbbell test specimens prepared in the same manner as in the room-temperature tensile test were heated in a 100°C dryer for 7 days and then conditioned at 23°C and 50% RH for 24 hours. The breaking stress (MPa) and breaking elongation (%) were then measured at a tensile speed of 200 mm / min using a tensile tester (Autograph AGS-J, manufactured by Shimadzu Corporation), and the elongation retention (%) was calculated. The elongation retention is the ratio (unit: %) of the breaking elongation at 100°C to the breaking elongation at room temperature. The higher the elongation retention value, the less likely the test specimen is to harden in a high-temperature environment, indicating better heat resistance.

[0097] ·Anti-coloring properties No. 3 dumbbell test pieces prepared in the same manner as in the room temperature tensile test were placed in a dryer at 100°C, and the samples were removed after 1 day, 2 days, 3 days, and 7 days, and the number of days until browning or blackening was measured. The longer the number of days until browning or blackening, the better the staining prevention properties can be judged to be. The criteria for judging staining are as follows. ○: No coloring △: Light coloring is observed (transparent) ×: Browning or blackening (opaque)

[0098] [Table 2]

[0099] 4. Production of thermoplastic resin composition (2) The (meth)acrylic polymers obtained in the above Production Examples and Comparative Production Examples were used as plasticizers to produce the following thermoplastic resin compositions. [Example 11] 100 parts of vinyl chloride resin (manufactured by Shin-Dai-Ichi Vinyl Corporation, trade name "ZEST 1300Z"), 70 parts of polymer P-1, 30 parts of calcium carbonate (manufactured by Maruo Calcium Co., Ltd., trade name "Super SSS"), 10 parts of titanium oxide (manufactured by Ishihara Sangyo Kaisha, Ltd., trade name "Tipake R820"), 1.2 parts of calcium stearate, 0.3 parts of zinc stearate, and 2 parts of an antioxidant (manufactured by BASF, trade name "Tinuvin B75") were mixed and kneaded at 160°C using a Laboplastomill to obtain thermoplastic resin composition R-15.

[0100] [Examples 12 to 20, Comparative Examples 5 to 8] Thermoplastic resin compositions R-16 to R-28 were obtained in the same manner as in Example 11, except that the types and amounts of plasticizers used were as shown in Table 3.

[0101] 5. Evaluation (2) The thermoplastic resin compositions R-15 to R-28 obtained in the above examples and comparative examples were evaluated as follows. The evaluation results are shown in Table 3.

[0102] <Cold resistance> (Evaluation of cold resistance of test pieces immediately after manufacture (before weather resistance testing)) The thermoplastic resin composition was press-molded at 190°C to obtain test pieces measuring 38 mm in length, 6 mm in width, and 2 mm in thickness. These test pieces were conditioned at 23°C and 50% RH for 24 hours. Then, using a brittleness temperature tester (S-type, manufactured by Toyo Seiki Seisakusho, Ltd.), the test pieces were checked for fracture at -20°C and -25°C (low-temperature impact resistance test). Three test pieces were used, and the cold resistance was evaluated according to the following criteria. ○: No fracture in any test specimens △: One or two test pieces were broken ×: All test pieces were destroyed (Evaluation of cold resistance of test specimens after weather resistance test) Test pieces of the same shape and size as those used in the cold resistance evaluation of test pieces immediately after production were placed in a metalling weather meter "DAIPLA METAL WEATHER KU-R5NCI-A" (trade name) manufactured by Daipla Wintes Co., Ltd., and subjected to an accelerated weather resistance test. The accelerated conditions were a metal halide lamp irradiance of 80mW / cm 2 The test environment was a temperature of 63°C, humidity of 70%RH, and a two-minute shower every two hours. This procedure was repeated for 1,200 hours, and then a low-temperature impact resistance test was conducted using the same evaluation method as above to evaluate cold resistance.

[0103] [Table 3]

[0104] As is clear from the results in Tables 2 and 3, (meth)acrylic polymers P-1 to P-10, which contain structural units having a cyclic ether group, have an SP value of 9.30 or more, and have a glass transition temperature of -75°C or less, exhibited good compatibility with vinyl chloride resin. Furthermore, thermoplastic resin compositions containing (meth)acrylic polymers P-1 to P-10 and vinyl chloride resin exhibited suppressed deterioration in mechanical properties and little change in color even when stored for long periods at a temperature of 100°C (Examples 1 to 10). Furthermore, even when stored for long periods at temperatures below -20°C, they were also resistant to deterioration in mechanical properties and showed good cold resistance after weathering tests (Examples 11 to 20).

[0105] In addition, in thermoplastic resin compositions containing (meth)acrylic polymers P-1 to P-10 together with vinyl chloride resin, the epoxy groups in the (meth)acrylic polymers P-1 to P-10 enhance compatibility with the vinyl chloride resin, thereby imparting excellent flexibility, and the epoxy groups function as radical scavengers, thereby suppressing dehydrochlorination reactions. Additionally, the epoxy groups in the (meth)acrylic polymers P-1 to P-10 trap hydrochloric acid generated from the vinyl chloride resin, thereby contributing to the suppression of the chain reaction of dehydrochlorination. As a result, it is believed that changes in the color tone of the vinyl chloride resin are suppressed in thermoplastic resin compositions containing the (meth)acrylic polymers P-1 to P-10.

[0106] In contrast, when (meth)acrylic polymer P-11, which does not contain a structural unit having a cyclic ether group, was used as a plasticizer (Comparative Examples 1 and 5), when (meth)acrylic polymer P-12, which has a glass transition temperature higher than -75 °C, was used as a plasticizer (Comparative Examples 2 and 6), and when (meth)acrylic polymer P-11, which does not contain a structural unit having a cyclic ether group, was used as a plasticizer and epoxidized soybean oil was blended (Comparative Examples 4 and 8), both heat resistance and cold resistance were inferior compared to Examples 1 to 20. Furthermore, when (meth)acrylic polymer P-13, which has an SP value lower than 9.30, was used as a plasticizer (Comparative Examples 3 and 7), the plasticizer was incompatible with the vinyl chloride resin, making molding difficult. In Comparative Example 7, many cracks were observed in the test specimen (2 mm thick) prepared for cold resistance evaluation, so it was determined that cold resistance evaluation was not possible.

[0107] From the above results, it was revealed that a thermoplastic resin composition excellent in flexibility, cold resistance, and heat resistance can be obtained by using a plasticizer containing a (meth)acrylic polymer having a weight average molecular weight of 3,000 or less, including a structural unit derived from a (meth)acrylic acid alkyl ester and a structural unit having a cyclic ether group having 3 to 5 ring members, an SP value of 9.30 or more, and a glass transition temperature of -75°C or less.

Claims

1. Contains a (meth)acrylic polymer having a weight average molecular weight of 3,000 or less, The (meth)acrylic polymer contains a structural unit (U1) derived from a (meth)acrylic acid alkyl ester and a structural unit (U2) having a cyclic ether group having 3 to 5 ring members, and has an SP value of 9.30 or more and a glass transition temperature of −75° C. or less.

2. 2. The plasticizer according to claim 1, wherein the (meth)acrylic polymer has a cyclic ether group content of 0.01 to 0.50 meq / g.

3. 2. The plasticizer according to claim 1, wherein the (meth)acrylic polymer has a carbon-carbon double bond content of 0.01 to 1.20 meq / g.

4. 2. The plasticizer according to claim 1, wherein the content of the structural unit (U1) is 90 mass% or more based on the total amount of structural units derived from monomers constituting the (meth)acrylic polymer.

5. The plasticizer according to claim 1, which is used for plasticizing vinyl chloride resins.

6. A thermoplastic resin composition comprising the plasticizer according to any one of claims 1 to 5 and a thermoplastic resin.

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