TWI913541B - Polymers, resin additives, compatibilizers, resin compositions and molded articles - Google Patents

Abstract

The purpose of this invention is to provide a polymer that improves the compatibility of polyester resins, represented by polybutylene terephthalate (PET), with other resins, thereby increasing the tensile elongation of the molded article. A polymer is provided, comprising a first polymer portion and a second polymer portion, wherein the first polymer portion is a polyester-based polymer, the second polymer portion has constituent units different from those constituting the first polymer portion, and the proportion of the first polymer portion in a total of 100 parts by mass is more than 20 parts by mass and less than 90 parts by mass, and the second polymer portion has constituent units derived from (meth)acrylate monomers.

Description

Polymers, resin additives, compatibilizers, resin compositions and molding compounds

This invention relates to a polymer, a resin additive, a resin composition, and a molded article.

Previously, attempts were made to achieve functionalities or performance improvements that could not be obtained with a single resin by mixing multiple resins. However, most combinations of resin types showed incompatibility, and therefore, the performance or functionality of the composite was often reduced compared to that of the single resin. Therefore, in order to improve the compatibility of multiple resin types, a compatibilizer was added.

Patent 1 discloses that polybutylene terephthalate resin, polystyrene resin, and carbon fiber exhibit good low warpage and mechanical properties by using polycarbonate as a compatibilizer. [Prior Art Documents] [Patent Documents]

[Patent Document 1] Japanese Patent Application Publication No. 2020-176159

[Problem to be Solved by the Invention] However, according to the research of the inventors, the compatibilizer described in Patent 1 is sometimes insufficient in improving the compatibility of polybutylene terephthalate (PET) resin and polystyrene resin. Therefore, one objective of the present invention is to provide a polymer, etc., that can improve the compatibility of polyester resins, represented by PET resin, with other resins, thereby resulting in excellent tensile elongation of the molded article. [Means of Solving the Problem]

One embodiment of the invention is a polymer having a first polymer portion and a second polymer portion, wherein the first polymer portion is a polyester polymer, the second polymer portion has constituent units different from those constituting the first polymer portion, and the proportion of the first polymer portion in a total of 100 parts by mass of the first polymer portion and the second polymer portion is more than 20 parts by mass and less than 90 parts by mass, and the second polymer portion has constituent units derived from (meth)acrylate monomers. [Effects of the Invention]

The present invention provides a polymer, etc., which, when mixed with two or more resins, can improve the compatibility of the resins, reduce phase separation, and also has excellent tensile elongation of the molded article.

The present embodiment will now be described in detail. Furthermore, the following description is of one embodiment of the present invention, and the present invention is not limited to the structure described below. The polymer of the present embodiment is a polymer comprising a first polymer portion as a polyester-based polymer and a second polymer portion having constituent units different from those constituting the first polymer portion (hereinafter, sometimes referred to as polymer A). By using polymer A as a resin additive for two or more matrix resins comprising polyester resins, the compatibility between the first matrix resin and the second matrix resin can be improved. Therefore, phase separation between the first matrix resin and the second matrix resin can be reduced.

<1. Polymer A> Polymer A of this embodiment is a polymer having a first polymer portion and a second polymer portion, wherein the first polymer portion is a polyester polymer, the second polymer portion has constituent units different from those constituting the first polymer portion, the proportion of the first polymer portion in 100 parts by mass of the total first and second polymer portions is more than 20 parts by mass and less than 90 parts by mass, and the second polymer portion has constituent units derived from (meth)acrylate monomers. Furthermore, in one embodiment of the present invention, the polymer having the first polymer portion and the second polymer portion may also be a polymer in which the first polymer portion and the second polymer portion are covalently bonded. In addition, one embodiment of the present invention also includes a polymer in which the first polymer is encapsulated or encapsulated by the second polymer even when the first polymer portion and the second polymer portion are not covalently bonded.

As a polymer formed by covalently bonding a first polymer portion and a second polymer portion, examples include block copolymers having both a first polymer portion and a second polymer portion. Furthermore, as a polymer in which the first polymer is encapsulated or clad within the second polymer, examples include polymers having a core-shell structure where the core portion includes one of the polymer portions of both the first and second polymer portions, and the shell portion includes the other polymer portion of both the first and second polymer portions. Moreover, a core-shell structure refers to a structure in which a portion called the core is encapsulated by a portion called the shell.

Preferably, polymer A is a polymer having a core-shell structure, with the first polymer portion constituting the shell portion of the core-shell structure. That is, polymer A is preferably a polymer in which the first polymer portion, being a polyester-based polymer, constitutes the shell portion of the core-shell structure, and the second polymer portion, having constituent units different from those constituting the first polymer portion, constitutes the core portion. Hereinafter, as representative examples, a preferred morphology of polymer A having this core-shell structure will be described in detail.

<1-1. First Polymer Portion> As described above, the first polymer portion is composed of a polyester polymer. Furthermore, in one embodiment of the present invention, the polyester polymer refers to a polymer in which the repeating unit is composed of a constituent unit containing an ester bond, and the polyester is synthesized by a polycondensation reaction of a dicarboxylic acid component and a diol component. By making the first polymer portion composed of a polyester polymer, the affinity with the first matrix resin, which is a polyester resin, is improved, resulting in improved compatibility between the first matrix resin and the second matrix resin.

There are no particular limitations on the dicarboxylic acid used; examples include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Examples of aromatic dicarboxylic acids include: terephthalic acid, isophthalic acid, phthalic acid, 2,5-norbornane dicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 4,4-hydroxybenzoic acid, fumaric acid, maleic anhydride, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, tetrahydrophthalic anhydride, tetrahydroterephthalic acid, sodium 5-sulfoisophthalate, lithium 5-sulfoisophthalate, trimellitic acid (anhydride), and pyromellitic acid (anhydride).

There are no particular restrictions on diol components, and examples include: ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, triethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, cyclohexanediol, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, ethylene oxide and propylene oxide adducts of bisphenol A, ethylene oxide and propylene oxide adducts of hydrogenated bisphenol A, polytetramethylene glycol, polyethylene glycol, polypropylene glycol and their modified forms, sodium sulfobutylene glycol, etc.

Furthermore, two or more dicarboxylic acid components can be used, and similarly, two or more diol components can also be used.

Furthermore, the first polymer portion may be composed of a variety of polymers having a variety of different constituent units. In this case, the constituent units may be exemplified as constituent units of the first polymer portion.

There are no particular limitations on the mass average molecular weight of the first polymer component, but for the sake of powder workability, it is preferably 3000 or higher, more preferably 5000 or higher, and especially preferably 7000 or higher. On the other hand, for the sake of suppressing the increase in viscosity when the matrix resin is added, the mass average molecular weight is preferably 200,000 or lower, more preferably 100,000 or lower, and especially preferably 50,000 or lower. Furthermore, this mass average molecular weight can be determined by gel permeation chromatography (GPC).

There are no particular limitations on the glass transition temperature of the first polymer portion, but to ensure powder recyclability, it is preferably 40°C or higher, more preferably 45°C or higher, and especially preferably 50°C or higher. On the other hand, to avoid powder micronization, the glass transition temperature is preferably 150°C or lower, more preferably 130°C or lower, and especially preferably 100°C or lower.

<1-2. Second Polymer Portion> The second polymer portion has constituent units different from those constituting the first polymer portion. The second polymer portion has constituent units derived from (meth)acrylate monomers. By having constituent units derived from (meth)acrylate monomers, the tensile elongation of the molded article is improved. Furthermore, the second polymer portion preferably has constituent units other than those derived from (meth)acrylate monomers, and these constituent units are preferably components with excellent affinity for the second matrix resin. Specifically, it is preferable that at least a portion of the constituent units of the second polymer portion are the same as at least a portion of the constituent units constituting the second matrix resin.

Regarding the constituent units derived from (meth)acrylate monomers constituting the second polymer portion, examples of (meth)acrylate monomers include: methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, butyl methacrylate, propyl acrylate, 2-ethylhexyl acrylate, glycidyl acrylate, propyl methacrylate, 2-ethylhexyl methacrylate, glycidyl methacrylate, phenyl acrylate, phenyl methacrylate, hydroxyethyl acrylate, 4-hydroxybutyl acrylate, benzyl acrylate, benzyl methacrylate, polyalkylene glycol monomethacrylate, or polyalkylene glycol monomethacrylate. Among these, from the viewpoint of the tensile elongation of the molded article, methyl methacrylate, butyl acrylate, glycidyl methacrylate, or polyalkylene glycol monomethacrylate are preferred.

There is no particular limitation on the proportion of (meth)acrylate monomers in the total of 100 parts by weight of all constituent units constituting the second polymer portion. However, it is preferable to have 5 parts by weight or more, and on the other hand, 80 parts by weight or less, in order to further improve the compatibility between the first matrix resin and the second matrix resin and further improve the tensile elongation of the molded article. More preferably, it is 8 parts by weight or more and 60 parts by weight or less.

As a constituent unit constituting the second polymer portion other than a constituent unit derived from (meth)acrylate monomers, it is preferably determined according to the structure of the second matrix resin used, for example, a constituent unit derived from an aromatic vinyl monomer. When the constituent unit constituting the second polymer portion includes a constituent unit derived from an aromatic vinyl monomer, when using, for example, a resin containing polystyrene as the second matrix resin, the second polymer portion exhibits good affinity with the polystyrene-containing resin. Consequently, better compatibility between the first matrix resin and the second matrix resin is expected. More preferably, the constituent unit constituting the second polymer portion is a constituent unit derived from an aromatic vinyl monomer having a 6-membered ring monocyclic structure, and more preferably a constituent unit derived from styrene that may have substituents. As a constituent unit derived from styrene which may have substituents, examples of constituent units derived from styrene or derived from α-methylstyrene can be listed, with a preference for constituent units derived from styrene.

There is no particular limitation on the proportion of aromatic vinyl monomers in the total of 100 parts by mass of all the constituent units of the second polymer portion. However, in order to further improve the compatibility between the first matrix resin and the second matrix resin, it is preferable to have 30 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 60 parts by mass or more, and especially preferably 70 parts by mass or more. On the other hand, it is preferable to have 95 parts by mass or less.

The second polymer portion may further have other constituent units. There is no particular limitation on the proportion of other constituent units in the total of 100 parts by mass of all constituent units of the second polymer portion, but in order to further improve the compatibility between the first matrix resin and the second matrix resin, it is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, particularly preferably 20 parts by mass or less, and on the other hand, it is 0 parts by mass or more.

Furthermore, the second polymer portion may be composed of a variety of polymers having a variety of different constituent units. Examples of constituent units used in this case may be those exemplified as constituent units of the second polymer portion.

When polymer A is added as a resin additive to the first matrix resin and the second matrix resin, in order to further improve the compatibility of the first matrix resin and the second matrix resin, the proportion of the first polymer in a total of 100 parts by weight of the first polymer portion and the second polymer portion is preferably more than 20 parts by weight and less than 90 parts by weight. More preferably, it is more than 20 parts by weight and less than 80 parts by weight; more preferably, it is more than 20 parts by weight and less than 70 parts by weight; more preferably, it is more than 20 parts by weight and less than 60 parts by weight; more preferably, it is more than 20 parts by weight and less than 50 parts by weight; more preferably, it is more than 20 parts by weight and less than 45 parts by weight; and most preferably, it is more than 20 parts by weight and less than 40 parts by weight.

<1-3. Manufacturing Method of Polymer A> There are no particular limitations on the manufacturing method of Polymer A when it has a core-shell structure; it can be manufactured using known methods such as suspension polymerization, solution polymerization, or emulsion polymerization. From the viewpoint of ease of manufacture, emulsion polymerization is preferred. That is, Polymer A is preferably obtained by emulsion polymerization of the monomeric component constituting the second polymeric part in the presence of the polymer constituting the first polymeric part. Furthermore, emulsion polymerization can be carried out by simultaneous addition and polymerization of the monomeric component, or by dropwise polymerization with phased addition.

More specifically, a monomeric component constituting a second polymer portion can be added to a solution in which the polymer constituting the first polymer portion is dispersed in any solvent, and emulsification can be performed using various mixers, followed by the addition of a polymerization initiator, and polymerization can then be carried out.

A solution formed by dispersing the polymer constituting the first polymer moiety in any solvent can be obtained, for example, by adding the polymer constituting the first polymer moiety to one or more solvents such as water, isopropanol, ethanol, methanol, acetone, methyl ethyl ketone, and diethyl ether, and stirring while applying shear. In terms of excellent dispersibility, the proportion of the first polymer in the dispersion solution is preferably 10% by mass or more, and from the viewpoint of operability considering the viscosity of the dispersion solution, it is preferably 50% by mass or less.

When a monomeric component constituting the second polymer moiety is added to a solution formed by dispersing the polymer constituting the first polymer moiety in any solvent, a surfactant may also be added. Examples of surfactants include anionic surfactants, cationic surfactants, and neutral surfactants. More than one of these may be used.

Polymerization initiators can be substances commonly used in free radical polymerization. Specific examples include persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate; and substances such as azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylpentanonitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile). Oil-soluble azo compounds such as nitriles, 2-phenylazo-4-methoxy-2,4-dimethylpentanonitrile, 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionic acid}, 2,2'-azobis{2-methyl-N-[2-(1-hydroxyethyl)]propionic acid}, 2,2'-azobis{2-methyl-N-[2-(1-hydroxyethyl)]propionic acid}, 2,2'-azobis{2-methyl-N-[2-(1-hydroxyethyl)]propionic acid} 2,2'-Azobis[2-(1-hydroxybutyl)]propane}, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane] and its salts, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] and its salts, 2,2'-azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane} Water-soluble azo compounds such as 2,2'-azobis(2-methylpropanedione) and its salts, and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropanedione], as well as organic peroxides such as benzoyl peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, tert-butyl peroxide-2-ethylhexanoate, and tert-butyl peroxide-isobutyrate. The polymerization initiator can be used alone or in combination with two or more others.

Preferred free radical polymerization methods in this invention include, for example, methods of polymerization using water-soluble polymerization initiators and methods of polymerization by redox reactions of organic peroxides with reducing agents such as ferrous sulfate or isoascorbic acid.

The amount of polymerization initiator used is preferably 0.05 to 1.0 parts by mass relative to 100 parts by mass of the monomers constituting the second polymer moiety, more preferably 0.1 parts by mass or more, and more preferably 0.3 parts by mass or less. Furthermore, when using a peroxide-based polymerization initiator, it can be combined with a reducing agent to form a redox-based polymerization initiator. The amount of reducing agent used is preferably 0.0001 to 1 part by mass relative to 100 parts by mass of the monomers constituting the second polymer moiety.

In addition, known chain transfer agents such as n-dodecyl mercaptan, ter-dodecyl mercaptan, and α-methylstyrene dimer can also be used as molecular weight adjusters to polymerize monomers.

There are no particular restrictions on the reaction temperature, which is usually above 45°C and below 80°C. In addition, there are no particular restrictions on the reaction time, which is usually above 30 minutes and below 300 minutes.

The latex of polymer A obtained by emulsification polymerization can be recovered as polymer powder by drying or freezing, or by coagulation. Of these, drying or coagulation based on spray drying is preferred.

In the case of spray drying, it is preferable to spray the latex of polymer A onto tiny droplets and then blow hot air onto them to dry them. As a device for generating droplets, any device such as a rotating disc type, a pressure nozzle type, or a dual-fluid nozzle type can be used.

When drying the latex of polymer A by blowing hot air, the temperature of the hot air is preferably above 100°C and below 200°C. If the hot air temperature is above 100°C, the latex can be dried sufficiently, and if it is below 200°C, the thermal decomposition of the obtained powder can be suppressed.

In the process of coagulation, latex of polymer A is added to hot water containing a dissolved coagulant, causing polymer A to salt out and separate. This is then refined and solidified into a moist state. The resulting substance is then dehydrated and dried. Examples of coagulants include inorganic salts such as aluminum chloride, aluminum sulfate, sodium sulfate, magnesium sulfate, sodium nitrate, and calcium acetate, or acids such as sulfuric acid, with calcium acetate being particularly preferred. These coagulants can be used alone or in combination, but when used in combination, it is preferable to choose a combination that does not form insoluble salts in water. For example, if calcium acetate is used in combination with sulfuric acid or its sodium salt, water-insoluble calcium salts will be formed, which is undesirable.

Furthermore, it is common knowledge in the art that the polymerization state of polymer A changes between the first and second polymer portions depending on its manufacturing method, but it is difficult to determine which polymerization state it becomes. For example, it is thought that polymer A obtained by emulsifying and polymerizing the monomeric components constituting the second polymer portion in the presence of the polymer constituting the first polymer portion has a different polymerization state than polymer A obtained by other methods, resulting in differences in structure or properties. However, determining the structure or properties to make such differences clear is technically impossible or entirely impractical.

[Resin Additives] Polymer A can be used as a resin additive such as a compatibilizer. Furthermore, Polymer A can be used directly as a resin additive, or any other additives can be formulated. Examples of known additives include: flame retardants, anti-dripping agents, antioxidants, UV absorbers, light stabilizers, mold release agents, lubricants, slip agents, colorants, fluorescent whitening agents, phosphorescent pigments, fluorescent dyes, and antistatic agents.

<2. Resin Composition> The resin composition of this embodiment includes polymer A and a first matrix resin. Furthermore, the resin composition may also include a second matrix resin, which is different from the first matrix resin. The proportion of polymer A relative to a total of 100 parts by weight of the first and second matrix resins is not particularly limited, but is preferably 0.1 to 30 parts by weight, more preferably 5 to 20 parts by weight. If the proportion of the resin additive is 0.1 parts by weight or more, the compatibility between the first and second matrix resins is further improved; if it is 30 parts by weight or less, the processability of the resin composition during manufacturing is excellent.

The resin composition of this embodiment may further include other components. For example, known additives may be formulated as needed to impart function or improve properties. Examples of such additives include: flame retardants, anti-dripping agents, antioxidants, ultraviolet absorbers, light stabilizers, mold release agents, lubricants, slip agents, colorants, fluorescent whitening agents, phosphorescent pigments, fluorescent dyes, antistatic agents, etc.

<2-1. First Matrix Resin> The first matrix resin is not particularly limited, but is preferably a polyester resin, such as a resin comprising at least one of the following groups: polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), polybutylene succinate (PBS), polyhydroxyalkanoic acid (PHA), and polylactic acid (PLA). Alternatively, recycled materials may also be used.

<2-2. Second Matrix Resin> There are no particular restrictions on whether the second matrix resin is different from the first matrix resin. For example, it can be a polystyrene-containing resin, such as polystyrene, high impact polystyrene (HIPS), and acrylonitrile butadiene styrene copolymers (ABS). Recyclable materials can also be used. From the viewpoint of improving compatibility, it is preferable that at least a portion of the constituent units constituting the second matrix resin are the same as at least a portion of the constituent units of the second polymer portion in polymer A.

The proportion of the first matrix resin in a total of 100 parts by weight of the first matrix resin and the second matrix resin is not particularly limited, but it is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, further preferably 20 parts by weight or more, and especially preferably 25 parts by weight or more. On the other hand, this proportion of the first matrix resin is preferably 95 parts by weight or less, more preferably 90 parts by weight or less, further preferably 80 parts by weight or less, and especially preferably 75 parts by weight or less.

<2-3. Manufacturing Method of Resin Composition> There are no particular limitations on the manufacturing method of resin composition. It can be manufactured by mixing polymer A, the first matrix resin, and the second matrix resin in powder form or by melt mixing. For example, a Henschel mixer, a Banbury mixer, a single-screw extruder, a twin-screw extruder, a twin-roller mixer, a kneader, or a Brabender mixer can be used for mixing or melt mixing.

<3. Molded Article> The resin composition of this embodiment can be molded to form a molded article. Alternatively, the resin composition of this embodiment can be mixed with other materials and then molded to form a molded article. That is, the molded article may also contain the resin composition. Furthermore, as a molding method, known methods can be used, such as compression molding, transfer molding, injection molding, blow molding, vacuum molding, extrusion molding, laminated molding, and calendering.

<4. Conclusion> As shown above, the present invention has the following characteristics.

[1] A polymer having a first polymer portion and a second polymer portion, wherein the first polymer portion is a polyester polymer, the second polymer portion has constituent units different from those constituting the first polymer portion, wherein the proportion of the first polymer portion in a total of 100 parts by mass of the first polymer portion and the second polymer portion is more than 20 parts by mass and less than 90 parts by mass, and the second polymer portion has constituent units derived from (meth)acrylate monomers.

[2] The polymer as described in [1], wherein the proportion of the constituent unit derived from the (meth)acrylate monomer in a total of 100 parts by mass of all constituent units constituting the second polymer portion is 5 parts by mass or more.

[3] The polymer as described in [1] or [2], wherein the second polymer portion further has constituent units derived from aromatic vinyl monomers.

[4] The polymer as described in [3], wherein the proportion of the constituent unit derived from the aromatic vinyl monomer in a total of 100 parts by weight of all constituent units constituting the second polymer portion is more than 30 parts by weight and less than 95 parts by weight.

[5] The polymer as described in any one of [1] to [4] has a core-shell structure, wherein the first polymer portion constitutes the shell portion of the core-shell structure and the second polymer portion constitutes the core portion of the core-shell structure.

[6] The polymer as described in any of [1] to [5] is obtained by emulsifying and polymerizing the monomeric component constituting the second polymer portion in the presence of the polymer constituting the first polymer portion.

[7] A resin additive comprising a polymer as described in any one of [1] to [6].

[8] A resin composition comprising: a polymer as described in any one of [1] to [6], and a polyester resin as a first matrix resin.

[9] The resin composition as described in [8] further includes a second matrix resin, which is a resin different from the first matrix resin.

[10] The resin composition as described in [9], wherein the second matrix resin is a resin containing polystyrene.

[11] A resin composition comprising: a polymer as described in [1], [5] or [6], a polyester resin as a first matrix resin, and a second matrix resin as a resin different from the first matrix resin, wherein at least a portion of the constituent units of the second polymer portion are identical to at least a portion of the constituent units constituting the second matrix resin.

[12] A molded article comprising a resin composition as described in any one of [8] to [11]. [Example]

The invention will now be described in one embodiment by way of example. In the embodiment, "parts" means "parts by mass".

<Tension modulus of elasticity and tensile elongation> Tension tests were conducted using a Tensilon universal testing machine (model name "RTC-1250A-PL", manufactured by Orientec Co., Ltd.) in accordance with Japanese Industrial Standards (JIS) K7139 to determine the tensile modulus of elasticity and tensile elongation of the molded parts.

<Phase Size> Phase size was observed on a portion of the molded body using a transmission electron microscope (TEM) (model "H-7600", manufactured by Hitachi). The test slides were prepared by staining with iron tetroxide for 12 hours followed by ruthenium tetroxide for 5 hours. The average diameter of the major and minor axes of any 30 dispersed phases in the TEM image was calculated as the phase size.

(Manufacturing Example 1) 240 parts of Nichigo-POLYESTER WR-905 (manufactured by Mitsubishi Chemical Co., Ltd.; solid content 20%), 90 parts of styrene (St) as a free radical polymerizable monomer, and 10 parts of glycidyl methacrylate (GMA) were placed in an aqueous dispersion solution of the polymer constituting the first polymer part and emulsified using a homogenizer to obtain a pre-emulsion of the free radical polymerizable monomer.

222 parts of pre-emulsion and deionized water were added to a flask including a mixer, reflux condenser, and temperature control device. Nitrogen bubbling was performed at a flow rate of 200 ml/min, while the temperature was raised to 50°C and maintained for 1 hour. Then, 0.7 parts of Percumyl P (manufactured by Nippon Oil Company) as a polymerization initiator, 0.002 parts of ferrous sulfate as a reducing agent, 0.006 parts of sodium ethylenediaminetetraacetic acid (EDTA), 0.3 parts of sodium formaldehyde sulfoxylate, and 10 parts of deionized water were added. The flow was switched to nitrogen, and polymerization began. After 1 hour, the temperature was raised to 60°C and maintained for 2 hours, followed by cooling to obtain a latex of polymer A1 in one state as described in this invention. The latex of the obtained polymer A1 was added to 460 parts of deionized water containing 5 parts by weight of calcium acetate, and then coagulated, washed, dehydrated and dried to obtain polymer A1 in powder form.

(Manufacturing Examples 2 to 9) Except for changes to the amount of the first polymer portion, the type of free radical polymerizable monomer, and the copolymerization amount as shown in Table 1 below, polymers A2 to A6 of the present invention and polymers B1 to B3 of the comparative examples were obtained using the same manufacturing method as in Manufacturing Example 1. One or two (meth)acrylates were used as free radical polymerizable monomers. In Table 1, the two (meth)acrylates are respectively referred to as "a1" and "a2". In Manufacturing Examples 2 to 7, at least one of glycidyl methacrylate (GMA), butyl acrylate (BA), methyl methacrylate (MMA), and polypropylene glycol monomethacrylate (Blemmer PP-800 manufactured by Nippon Oil Co., Ltd.) was used as the free radical polymerizable monomer.

<Polymerization Stability> As for the polymerization stability of each polymer, if the free radical polymerizable monomer remains in an emulsion state through the first polymer throughout the polymerization process, it is evaluated as "suitable"; if it separates, it is evaluated as "unsuitable".

(Example 1) 70 parts of polybutylene terephthalate (PBT, manufactured by Mitsubishi Engineering Plastics Co., Ltd.: Novaduran 5010R) as the first matrix resin, 30 parts of polystyrene (PS, manufactured by Toyo Styrol Co., Ltd.: Toyo Styrol GP200) as the second matrix resin, and 10 parts of polymer A1 produced in Manufacturing Example 1 were placed in a polyethylene bag. After manually mixing by shaking the polyethylene bag thoroughly by hand, the mixture was melt-kneaded at 250°C using a biaxial extruder (manufactured by Toshiba Machine Co., Ltd., trade name: TEM35B), and the extruded strands were cut to obtain granules. The obtained particles were molded using an injection molding machine (manufactured by Toshiba Machinery Co., Ltd., trade name: IS100EN) at a molding temperature of 250°C and a mold temperature of 60°C to produce a dumbbell-shaped molded body according to JIS K7139, thus obtaining the molded body of Example 1. The molded body was subjected to cross-sectional observation and tensile testing using transmission electron microscopy (TEM). A TEM image of the cross-section of the molded body is shown in Figure 1. The average diameter of the major diameter portion of any 30 dispersed phases in the TEM image is 0.58 μm. Furthermore, the tensile modulus of elasticity of the molded body obtained by the tensile test is 2.2 GPa, and the tensile elongation is 3.1%.

(Examples 2 to 8) Except for changing the second matrix resin to impact-resistant polystyrene (HIPS, Toyo Styrol H350), or changing the ratio of the first matrix resin and the second matrix resin, the type of polymer used, and the amount added as shown in Table 2 below, the molded articles were obtained and evaluated in the same manner as in Example 1.

(Comparative Example 1) Except that the polymer A1 obtained by Manufacturing Example 1 was not added, a resin composition and a molded article were manufactured by the same method as in Example 1 to obtain the molded article of Comparative Example 1. Cross-sectional observation and tensile tests were performed on the molded article using TEM. A TEM photograph of the cross-section of the molded article is shown in Figure 2. The average diameter of the major diameter portion of any 30 dispersed phases in the TEM photograph is 1.01 μm. Furthermore, the tensile modulus of elasticity of the molded article obtained by the tensile test is 2.1 GPa, and the tensile elongation is 2.9%.

(Comparative Examples 2 to 7) Except for changing the second matrix resin to impact-resistant polystyrene (HIPS, Toyo Styrol H350) or changing the presence or absence of polymers, the type of polymers used and the amount added as shown in Table 2 below, the molded articles were obtained and evaluated in the same manner as in Example 1.

[Table 1] First polymer part Second polymer part The proportion (parts by mass) of the first polymer component. Name Polymer stability Polyester polymers a1 The proportion (parts by mass) of a1 a2 The proportion of a2 (parts by mass) Aromatic vinyl Proportion of aromatic vinyl groups (parts by mass) Manufacturing example 1 WR-905 GMA 10 - - St 90 38 Polymer A1 Suit Manufacturing example 2 WR-905 GMA 10 - - St 90 26 Polymer A2 Suit Manufacturing example 3 WR-905 BA 10 - - St 90 38 Polymer A3 Suit Manufacturing example 4 WR-905 BA 5 MMA 45 St 50 26 Polymer A4 Suit Manufacturing example 5 WR-905 BA 5 MMA 45 St 50 38 Polymer A5 Suit Manufacturing example 6 WR-905 Blemmer PP-800 10 MMA 40 St 50 38 Polymer A6 Suit Manufacturing example 7 WR-905 BA 5 MMA 45 St 50 19 Polymer B1 Suit Manufacturing example 8 WR-905 GMA 10 - - St 90 19 Polymer B2 Suit Manufacturing example 9 WR-905 - - - - St 100 38 Polymer B3 Not suitable

[Table 2] First base resin Second matrix resin Resin additives Tensile elastic modulus (GPa) Elongation at break (%) Phase size (μm) Kind Mixing quantity (parts by weight) Kind Mixing quantity (parts by weight) Kind Mixing quantity (parts by weight) Implementation Example 1 PBT 70 PS 30 Polymer A1 10 2.2 3.1 0.58 Implementation Example 2 PBT 70 PS 30 Polymer A1 5 2.1 3 0.66 Implementation Example 3 PBT 90 PS 10 Polymer A1 5 1.8 11.9 1.22 Implementation Example 4 PBT 70 PS 30 Polymer A2 5 2.1 3.1 0.6 Implementation Example 5 PBT 70 PS 30 Polymer A3 5 2.2 3.6 0.5 Implementation Example 6 PBT 70 PS 30 Polymer A4 5 2.1 4.1 0.44 Implementation Example 7 PBT 70 PS 30 Polymer A5 5 2.3 4.9 0.37 Implementation Example 8 PBT 70 HIPS 30 Polymer A6 5 1.8 12 2.11 Comparative example 1 PBT 70 PS 30 - - 2.1 2.9 1.01 Comparative example 2 PBT 90 PS 10 - - 1.7 9.2 3.62 Comparative example 3 PBT 70 HIPS 30 - - 1.8 10.5 3.31 Comparative example 4 PBT 70 PS 30 Polymer B1 5 2.2 2.8 Undetermined Comparative example 5 PBT 70 PS 30 Polymer B2 5 2.1 2.9 0.91 Comparative example 6 PBT 70 PS 30 Polymer B3 5 1.9 2.5 6.53 Comparative example 7 PBT 70 PS 30 WR-905 5 1.9 2.8 Undetermined

Based on the above results, it can be seen that when the ratio of the first matrix resin to the second matrix resin is 70/30 (first matrix resin/second matrix resin), compared to Comparative Example 1 which does not use the polymer of the present invention, the average diameter of the dispersed phase in Example 1 using the polymer of the present invention is significantly smaller. In addition, the tensile elongation of the molded article is increased by 7% when Comparative Example 1 is set to 100%. Furthermore, it can be seen that, compared to Comparative Example 1, Examples 4 and 6, which use the polymer of the present invention, also show an increase in the average diameter of the dispersed phase and the tensile elongation of the molded article. Based on the above results, it can be seen that by using the polymer of this invention as a resin additive, the compatibility between the first matrix resin and the second matrix resin and the tensile elongation of the molded article are improved. The increased tensile elongation results in better toughness of the molded article, thus increasing its industrial value.

Furthermore, it was confirmed that in Comparative Example 5, which used a polymer with a smaller proportion of the first polymer portion, the average diameter of the dispersed phase was smaller in Example 2, which had a sufficient proportion of the first polymer portion. Additionally, the tensile elongation of the molded article was increased by 3% when Comparative Example 5 was set to 100%. Similarly, in Comparative Example 4, which used a polymer with a smaller proportion of the first polymer portion, and in Example 7, which had a sufficient proportion of the first polymer portion, the average diameter of the dispersed phase and the tensile elongation of the molded article were also increased. Based on the above results, it can be seen that by using a polymer of the present invention as a resin additive, the compatibility between the first matrix resin and the second matrix resin, as well as the tensile elongation of the molded article, are improved. The increased tensile elongation results in better toughness of the molded article, thus increasing its industrial applicability.

Furthermore, it was confirmed that, compared to Comparative Example 6, which used a polymer that did not contain (meth)acrylate monomers in the second polymer portion, Examples 2, 5, and 7, which contained (meth)acrylate monomers in the second polymer portion, had a smaller average diameter of dispersed phase and an increased tensile elongation of the molded article. It was confirmed that, when the tensile elongation of Comparative Example 6 was set to 100%, the tensile elongation of Examples 2, 5, and 7 increased by 20%, 44%, and 96%, respectively. Based on the above results, it can be seen that by using a polymer of the present invention as a resin additive, the compatibility between the first matrix resin and the second matrix resin, as well as the tensile elongation of the molded article, are improved. The increased tensile elongation improves the toughness of the molded article, thus increasing its industrial applicability.

As can be seen, compared to Comparative Example 2, which does not use the polymer of the present invention, in Example 3, where the ratio of the first matrix resin to the second matrix resin is 90/10 (first matrix resin/second matrix resin), the average diameter of the dispersed phase is significantly reduced. Furthermore, the tensile elongation of the molded article is increased by 29% when Comparative Example 2 is set to 100%. Based on the above results, it can be seen that by using the polymer of the present invention as a resin additive, the compatibility between the first and second matrix resins and the tensile elongation of the molded article are improved. The increased tensile elongation improves the toughness of the molded article, thus increasing its industrial applicability.

As can be seen, compared to Comparative Example 3 which does not use the polymer of the present invention, in Example 8 where the second matrix resin uses HIPS, the average diameter of the dispersed phase is significantly smaller. Furthermore, the tensile elongation of the molded article is increased by 14% when Comparative Example 3 is set to 100%. Based on the above results, it can be seen that by using the polymer of the present invention as a resin additive, the compatibility between the first and second matrix resins and the tensile elongation of the molded article are improved. The increased tensile elongation improves the toughness of the molded article, thus increasing its industrial application value.

In Comparative Example 7, which uses a polymer without the second polymer portion, the polymer exhibits poor polymerization stability, and the tensile elongation of the molded article is worse than that of Comparative Example 1, which does not contain the polymer. Therefore, its industrial applicability is poor. [Industrial Applicability]

The polymer of this invention can be suitably used as a compatibilizer, which can reduce phase separation of resins when mixed with two or more resins, and also provides excellent tensile elongation when the resin composition containing the polymer is formed into a molded article.

without

Figure 1 is a cross-sectional photograph of the molded body of Example 1 observed using a transmission electron microscope. Figure 2 is a cross-sectional photograph of the molded body of Comparative Example 1 observed using a transmission electron microscope.

Claims (15)

A polymer having a first polymer portion and a second polymer portion, wherein the first polymer portion is a polyester polymer, the second polymer portion has constituent units different from those constituting the first polymer portion, the proportion of the first polymer portion in a total of 100 parts by mass of the first polymer portion and the second polymer portion is more than 20 parts by mass and less than 70 parts by mass, and the second polymer portion has constituent units derived from (meth)acrylate monomers. The polymer as claimed in claim 1, wherein the proportion of the constituent unit derived from the (meth)acrylate monomer in a total of 100 parts by mass of all constituent units constituting the second polymer portion is 5 parts by mass or more. The polymer as described in claim 1, wherein the second polymer portion further has constituent units derived from aromatic vinyl monomers. The polymer as claimed in claim 3, wherein the proportion of the aromatic vinyl monomer-derived constituent unit in a total of 100 parts by weight of all constituent units constituting the second polymer portion is 30 parts by weight or more and 95 parts by weight or less. The polymer as described in claim 1 has a core-shell structure, wherein a first polymer portion constitutes the shell portion of the core-shell structure, and a second polymer portion constitutes the core portion of the core-shell structure. The polymer as described in claim 1 is obtained by emulsifying and polymerizing the monomeric components constituting the second polymer portion in the presence of the polymer constituting the first polymer portion. The polymer as claimed in claim 1, wherein the proportion of the first polymer portion in a total of 100 parts by weight of the first polymer portion and the second polymer portion is more than 20 parts by weight and less than 50 parts by weight. A resin additive comprising the polymer described in any one of claims 1 to 7. A compatibilizer comprising the polymer described in any one of claims 1 to 7. A resin composition comprising: a polymer as described in any one of claims 1 to 7, and a polyester resin as a first matrix resin. The resin composition as described in claim 10 further comprises a second matrix resin, the second matrix resin being different from the first matrix resin. The resin composition as described in claim 11, wherein the second matrix resin is a polystyrene-containing resin. A resin composition comprising: a polymer as described in claims 1, 5, or 6; a polyester resin as a first matrix resin; and a second matrix resin as a resin different from the first matrix resin, wherein at least a portion of the constituent units of the second polymer portion are identical to at least a portion of the constituent units constituting the second matrix resin. The resin composition as described in claim 13, wherein the polymer comprises 0.1 to 30 parts by weight relative to a total of 100 parts by weight of the first matrix resin and the second matrix resin. A molded article comprising a resin composition as described in any one of claims 10 to 14.