Resin particles, resin powder, molded body, method for producing resin particles, and method for producing second molded body

Abstract

Provided are resin particles having excellent dispersibility in a base material resin. The present invention provides resin particles, the resin particles containing a polymer having a structure derived from a chain transfer agent having an SP value of 9.0-20.0 (cal / cm3)1 / 2 obtained using the Fedors method.

Description

Resin particles, resin powder, molded article, method for producing resin particles, and method for producing a second molded article

[0001] The present invention relates to resin particles, resin powder, molded articles, a method for producing resin particles, and a method for producing a second molded article.

[0002] Resin particles are widely used in various applications, including toner components, paint additives, optical materials, cosmetics, and molding resins. In each of these applications, resin particles with uniform particle size are sometimes required to exhibit properties such as light diffusion, matte finish, and antiblocking. Resin particles are often dispersed in a base resin, and good dispersibility in the base resin is also required. In particular, in recent years, from an environmental perspective, it is sometimes required that resin particles can be melted together with the base resin when recycling resin molded products containing resin particles. For example, Patent Document 1 describes resin fine particles with high monodispersibility and a manufacturing method by seed polymerization.

[0003] Japanese Unexamined Patent Publication No. 62-121701

[0004] However, conventional resin particles sometimes exhibited insufficient dispersibility in the base resin. This invention was made in view of these circumstances and provides resin particles with excellent dispersibility in the base resin.

[0005] According to the present invention, the resin particles have an SP value of 9.0 to 20.0 (cal / cm³) according to the Fedors method. ３ ) １／２ Resin particles are provided, which include a polymer having a structure derived from a chain transfer agent.

[0006] Through diligent research, the inventors discovered that by incorporating a polymer having a structure derived from a chain transfer agent with a specific SP value into resin particles, resin particles with excellent dispersibility in a base resin can be obtained, leading to the completion of the present invention.

[0007] The following are examples of various embodiments of the present invention. The embodiments shown below can be combined with each other. [1] Resin particles, wherein the resin particles have an SP value of 9.0 to 20.0 (cal / cm³) according to the Fedors method.３ ) １／２ Resin particles containing a polymer having a structure derived from a chain transfer agent which is. [2] The resin particles according to [1], having an acetone-insoluble fraction of 10% or less. [3] The resin particles according to [1] or [2], having a weight-average molecular weight of the acetone-soluble fraction of 5000 to 200000. [4] A resin powder containing the resin particles according to any one of [1] to [3], wherein the number-based particle size distribution of the equivalent circle diameter of the resin powder is obtained by image analysis of a scanning electron microscope, and when the number-average particle diameter is D, the total content ratio of particles having a particle diameter of 0.5D or less and particles having a particle diameter of 1.5D or more is 10% or less. [5] A molded article having at least one of the resin particles according to [1] to [3] and the resin powder according to [4], and a base resin. [6] A method for producing resin particles, having a polymerization step, wherein in the polymerization step, a raw material monomer is polymerized in a solvent containing a chain transfer agent having an SP value of 9.0 to 20.0 (cal / cm ３ ) １／２ to obtain a polymer. [7] A method for producing a second molded article by producing a second molded article from a raw material containing a first molded article, wherein the first molded article is the molded article according to [5], and the production method includes a melting step, and in the melting step, the raw material is heated to 100 to 300 ° C to melt at least a part of the base resin in the first molded article.

[0008] The resin particles and resin powder according to the present invention are excellent in dispersibility in a base resin, so that a molded article in which the resin particles are uniformly dispersed in the base resin can be obtained. The molded article according to an embodiment of the present invention has the resin particles uniformly dispersed in the base resin, so that in various applications, there are few defects and the performance such as desired optical properties and mechanical properties can be exhibited. According to the method for producing resin particles according to an embodiment of the present invention, resin particles excellent in dispersibility in a base resin can be obtained. According to the method for producing a molded article according to an embodiment of the present invention, a molded article having few fine particles and coarse particles and having the resin particles uniformly dispersed in the base resin can be obtained.

[0009] The present invention will be described in detail below with reference to embodiments of the present invention. The present invention is not limited in any way by these descriptions. The features of the embodiments of the present invention shown below can be combined with each other. Furthermore, each feature constitutes an invention independently. Any number of zeros (for example, one or two) may be added to the end of the numerical values ​​disclosed in the following description. For example, one or two zeros may be added after "1.4" to make it "1.40" or "1.400".

[0010] 1. Resin Particles and Resin Powder 1.1 Polymer The resin particles according to the present invention have an SP value of 9.0 to 20.0 (cal / cm³) according to the Fedors method. ３ ) １／２It contains a polymer having a structure derived from a chain transfer agent. Since the resin particles according to the present invention contain a polymer having a structure derived from a chain transfer agent having a specific SP value, it is presumed that they have excellent dispersibility in the base resin. Further, since the resin particles according to one embodiment of the present invention are polymerized using a chain transfer agent having a specific SP value, there are few fine particles and coarse particles, and it is easy to obtain a resin powder with a uniform particle size. The mechanism is not clear, but it is presumed to be as follows. In so-called heterogeneous reaction systems such as seed polymerization, emulsion polymerization, and soap-free emulsion polymerization, the reaction proceeds by supplying a part of the monomer from the monomer droplets to the continuous phase (for example, water) and then to the particle nuclei or particles during the growth reaction. Therefore, in these heterogeneous reaction systems, the solubility of the monomer in the continuous phase is also one of the important factors to be considered in the progress of the reaction. Here, by using a chain transfer agent having a specific SP value, the polymerization reaction in reaction fields other than the target particles (in the continuous phase or monomer droplets) is less likely to occur, so it is considered that the generation of fine particles and coarse particles is suppressed. According to the resin particles according to one embodiment of the present invention, a molded body with uniform particle size and such particles uniformly dispersed can be obtained. Such a molded body has few defects and can exhibit desired performance such as optical properties and mechanical properties. When a molded body containing conventional resin particles is melted and remolded, the resin particles may remain unmolten, making recycling difficult in some cases. However, the molded body according to one embodiment of the present invention has a structure in which there are few fine particles and coarse particles and the resin powder with a uniform particle size is uniformly dispersed. Therefore, when it is melted and remolded, the resin particles are easily melted. Even if only a part of them melts, the remaining molten resin particles have a structure uniformly dispersed in the base resin, and it has excellent recyclability.

[0011] The above polymer has a structure derived from a chain transfer agent having an SP value of 9 to 20 (cal / cm ３ ) １／２ It has a structure derived from a chain transfer agent having an SP value of 9 to 20 (cal / cm ３ ) １／２ It can be a polymer obtained by polymerizing a raw material monomer in the presence of a chain transfer agent having an SP value of 9.0 to 20.0 (cal / cm ３ )１／２ and is 9.2 to 15.0 (cal / cm ３ ). １／２ is preferable, and 9.5 to 11.0 (cal / cm ３ ). １／２ is more preferable. When the SP value is within the above range, the dispersibility in the base resin is excellent, and coarse particles and fine particles can be further reduced. The SP value is, for example, 9, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0, 18.5, 19.0, 19.5, 20.0 (cal / cm ３ ). １／２ and may be within the range between any two of the numerical values exemplified herein.

[0012] The SP value can be the solubility parameter calculated by the Fedors method and is calculated based on the molecular structure (atomic group) and its number. The method for calculating the SP value by the Fedors method can be based on the value calculated by the formula (28) described on page 153, using the numerical values (heat of vaporization and molar volume at 25 °C of atoms or functional groups) described on page 152 of Polymer Engineering and Science, February 1974, Vol. 14, No. 2, P147 - 154 (Table 5). The SP value can be the solubility parameter at 25 °C.

[0013] Examples of chain transfer agents with an SP value within the above range include thioglycolic acid, alkyl esters of thioglycolic acid, alkoxyalkyl esters of thioglycolic acid, 3-mercaptopropionic acid, alkyl esters of 3-mercaptopropionic acid, alkoxyalkyl esters of 3-mercaptopropionic acid, 2-mercaptoethanol, 1-thioglycerol, thioacetic acid, cysteine, and thiosalicylic acid. Chain transfer agents with an SP value within the above range may have ester bonds. Chain transfer agents with an SP value within the above range may have 3 to 20 carbon atoms, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20, and may be within the range between any two of the values ​​exemplified here. Chain transfer agents with an SP value within the above range may have an alkyl group with 2 to 10 carbon atoms and / or an alkylene group with 2 to 10 carbon atoms. The chain transfer agent whose SP value is within the above range may be a compound represented by R-SH. Here, R can be an organic group and can be the residue obtained by removing -SH from the above chain transfer agent (compound represented by R-SH). In this case, the SP value is 9 to 20 (cal / cm³). ３ ) １／２ A polymer having a structure derived from a chain transfer agent can be one that has a structure represented by -S-R at its terminal (a structure obtained by removing H from a compound represented by R-SH). The presence or absence of a terminal structure can be confirmed, for example, by analysis using infrared spectroscopy, nuclear magnetic resonance spectroscopy, or mass spectrometry.

[0014] The above polymer has an SP value of 9.0 to 20.0 (cal / cm³) per 100 parts by mass of polymer. ３ ) １／２ The content of the chain transfer agent-derived structure can be 0.001 to 10 parts by mass, preferably 0.01 to 8 parts by mass, and more preferably 0.1 to 5 parts by mass. The SP value is 9.0 to 20.0 (cal / cm³). ３ ) １／２The content of the chain transfer agent-derived structure is, for example, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 parts by mass, and may be within the range of any two of the values ​​exemplified here. The content of the chain transfer agent-derived structure can be confirmed, for example, by analysis using infrared spectroscopy, nuclear magnetic resonance spectroscopy, and mass spectrometry.

[0015] SP value is 9.0-20.0 (cal / cm³) ３ ) １／２ A polymer having a structure derived from a chain transfer agent can be a polymer containing monomer units derived from a radical polymerizable monomer. The radical polymerizable monomer is not particularly limited. The above polymer has an SP value of 8.0 to 18.0 (cal / cm²). ３ ) １／２ The polymer may have monomer units derived from a monomer, preferably 8.2 to 16.0, and more preferably 8.4 to 14.0. The SP values ​​of the monomers constituting the polymer (radical polymerizable monomers) are, for example, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0 (cal / cm³). ３ ) １／２ The values ​​may be within the range of any two of the values ​​exemplified here. Furthermore, the monomers constituting the polymer preferably have an absolute difference of 0 to 6.8 in SP value from the chain transfer agent, more preferably 0 to 4.5, for example, 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 6.8, and may be within the range of any two of the values ​​exemplified here.

[0016] The above polymer preferably contains at least one of (meth)acrylic monomer units and styrene monomer units as monomer units.

[0017] "(Meth)acrylic" is used as a general term for acrylic and methacrylic. Similarly, "(Meth)acrylic monomer" is used as a general term for acrylate and methacrylate. Examples of (meth)acrylic monomers include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, secondary butyl acrylate, secondary butyl methacrylate, tertiary butyl acrylate, tertiary butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, isooctyl acrylate, isooctyl methacrylate, n-nonyl acrylate, n-nonyl methacrylate, isononyl acrylate, and isononyl methacrylate. These may be used individually or in combination of two or more.

[0018] Examples of styrene monomer units include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, ethylstyrene, p-t-butylstyrene, α-methylvinyltoluene, dimethylstyrene, bromostyrene, and dibromostyrene. These can be used individually or in combination of two or more.

[0019] The total content of (meth)acrylic monomer units and styrene monomer units per 100% by mass of the polymer may be, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100% by mass, and may be within the range of any two of the values ​​exemplified here. The content of (meth)acrylic monomer units per 100% by mass of the polymer may be, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100% by mass, and may be within the range of any two of the values ​​exemplified here. The content of monomer units other than (meth)acrylic monomer units and styrene monomer units per 100% by mass of the polymer may be, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50% by mass, and may be within the range of any two of the values ​​exemplified here.

[0020] A polymer according to one embodiment of the present invention may have a structure derived from a polyfunctional monomer. Examples of polyfunctional monomers include compounds having two or more radical polymerization groups in the molecule and capable of functioning as a crosslinking agent. The polyfunctional monomer is not particularly limited, but examples include polyfunctional (meth)acrylates and aromatic polyene monomers such as divinylbenzene. Examples of polyfunctional (meth)acrylates include difunctional, trifunctional, tetrafunctional or more (meth)acrylates.

[0021] Examples of difunctional (meth)acrylates include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyoxyethylene di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,9-nonanediol di(meth)acrylate.

[0022] Examples of trifunctional (meth)acrylates include trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, and tris(2-(meth)acryloxyethyl isocyanurate).

[0023] Examples of tetra(meth)acrylate compounds with four or more functions include pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, ethoxylated dipentaerythritol tetra(meth)acrylate, propoxylated dipentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ethoxylated ditrimethylolpropane tetra(meth)acrylate, and ethoxylated ditrimethylolpropane tetra(meth)acrylate, as well as dipentaerythritol penta(meth)acrylate and dipentaerythritol hexa(meth)acrylate.

[0024] The polymer according to the present invention preferably has a polyfunctional monomer unit content of 0.01% by mass or less relative to 100% by mass of the polymer, for example, 0, 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.010% by mass, and may be within the range of any two of the values ​​exemplified herein. When the polyfunctional monomer unit content is within the above numerical range, the recyclability of the resin particles is further improved. The polymer according to the present invention does not need to contain polyfunctional monomer units.

[0025] The glass transition temperature (Tg) of the resin is not particularly limited, but is preferably 40 to 180°C, more preferably 65 to 160°C, and even more preferably 90 to 140°C. A Tg within this range is preferable because it makes it easier to maintain the particle shape during the molding process and also makes it easier for the resin particles to melt into the base resin when recycling the molded article containing the resin particles, resulting in excellent recyclability.

[0026] The resin particles according to the present invention have an SP value of 9.0 to 20.0 (cal / cm³). ３ ) １／２ The polymer may contain one or more polymers having a structure derived from a chain transfer agent. Furthermore, the resin particles according to the present invention have an SP value of 9.0 to 20.0 (cal / cm³). ３ ) １／２ The polymer may also contain components other than polymers having a structure derived from a chain transfer agent (for example, other polymers). The SP value per 100% by mass of resin particles according to the present invention is 9.0 to 20.0 (cal / cm³). ３ ) １／２ The content of the polymer having a structure derived from the chain transfer agent is, for example, 70, 75, 80, 85, 90, 95, or 100% by mass, and may be within the range of any two of the values ​​exemplified here.

[0027] 1.2 Characteristics of Resin Particles The resin particles according to one embodiment of the present invention preferably have an acetone-insoluble content of 10% or less, more preferably 5% or less, and even more preferably 2% or less. The acetone-insoluble content may be, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10%, and may be within the range of any two of the values ​​exemplified herein. It is preferable that the acetone-insoluble content be within the above range because it is easily melted by heating or organic solvents, and also has excellent recyclability.

[0028] The acetone-insoluble fraction is calculated from the weight of the insoluble portion (W2) obtained by immersing approximately 1 g of weighed dry resin particles (W1) in 100 g of acetone, shaking at 50°C for 5 hours, centrifuging at 10,000 rpm for 60 minutes using a centrifuge, removing the supernatant, and drying in an oven at 80°C for 3 hours, using the following formula: W2 / W1 × 100 (%). The acetone-insoluble fraction can be controlled by adjusting the manufacturing conditions of the resin particles, specifically by adjusting the type and amount of raw material monomers, the type and amount of each monomer unit in the polymer (for example, the presence and amount of polyfunctional monomers), and by adjusting the polymerization conditions to adjust the weight-average molecular weight of the polymer.

[0029] The weight-average molecular weight (Mw) of the acetone-soluble portion of the resin particles of the present invention is not particularly limited, but is preferably 5,000 to 200,000, more preferably 10,000 to 150,000, and even more preferably 55,000 to 100,000. The weight-average molecular weight (Mw) of the acetone-soluble portion is, for example, 5,000, 10,000, 20,000, 30,000, 40,000, 50,000, 55,000, 60,000, 70,000, 80,000, 90,000, 100,000, 110,000, 120,000, 130,000, 140,000, 150,000, 160,000, 170,000, 180,000, 190,000, and 200,000, and may be within the range of any two of the values ​​exemplified herein. When the Mw of acetone-soluble components is within the aforementioned range, it is preferable because it is easily melted by heating or organic solvents, and also has excellent recyclability.

[0030] The Mw of the acetone-soluble portion can be measured by gel permeation chromatography (GPC) using the supernatant after centrifugation in the acetone-insoluble portion measurement procedure, and can be specifically determined by the method described in the examples. The production conditions of the resin particles can be controlled by adjusting the type and amount of raw material monomers, adjusting the type and amount of each monomer unit in the polymer (for example, the presence and amount of polyfunctional monomers), and especially by adjusting the polymerization conditions to adjust the weight-average molecular weight of the polymer.

[0031] 1.3 Resin Powder The resin powder according to one embodiment of the present invention may contain the resin particles of the present invention. In the resin powder according to one embodiment of the present invention, when the particle size distribution based on the number of particles with an equivalent circular diameter of the resin particles is obtained by image analysis of a scanning electron microscope (SEM), and the number-average particle diameter is D, it is preferable that the total content of particles with a particle diameter of 0.5D or less (also called "fine particles") and particles with a particle diameter of 1.5D or more (also called "coarse particles") is 10.0% or less. The total content of fine particles and coarse particles is preferably 8.0% or less, more preferably 5.0% or less, and even more preferably 3.0% or less. The total content of fine and coarse particles can be, for example, 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, or 10.0%, and may be within the range of any two of the values ​​exemplified here. It is preferable that the total content of fine and coarse particles falls within the above range because it offers excellent versatility as an additive. In particular, from the viewpoint of productivity, it is preferable that the total content of fine and coarse particles falls within the above range after the polymerization process or a process for simply filtering out aggregates generated secondarily after the polymerization process, and before the classification process.

[0032] The number-average particle size D of the resin powder is not particularly limited, but is preferably 0.01 to 1000 μm, more preferably 0.05 to 500 μm, and even more preferably 0.1 to 100 μm. The number-average particle size D may be, for example, 0.01, 0.05, 0.1, 0.5, 1, 5, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, or 1000 μm, and may be within the range of any two of the values ​​exemplified herein.

[0033] The number-average particle size D is the particle size at which the cumulative value of the particle size distribution based on the equivalent circle diameter of 500 primary particles randomly selected by image analysis from single or multiple images taken using a SEM at a magnification of 20 to 90% of the total area of ​​resin particles in one field of view, where 50 to 1000 resin particles can be observed per field of view, and the total area of ​​resin particles in one field of view is 20 to 90% of the area, is 50%. The number-average particle size D, the content of particles with a particle size of 0.5D or less (fine particles), and the content of particles with a particle size of 1.5D or more (coarse particles) can be specifically determined by the method described in the examples. Furthermore, the number-average particle size D, the content of particles with a particle size of 0.5D or less (fine particles), and the content of particles with a particle size of 1.5D or more (coarse particles) can be controlled by adjusting the manufacturing conditions of the resin particles, for example, the type and amount of the chain transfer agent, and by adjusting the polymerization conditions.

[0034] 1.4 Applications The resin particles and resin powder according to one embodiment of the present invention can be widely used in various applications such as toner components, additives for paints, additives for films, optical materials, cosmetics, and molding resins. For example, the resin particles and resin powder according to one embodiment of the present invention can be used for forming molded articles containing these and a base resin. The resin particles and resin powder according to one embodiment of the present invention can be resin particles or resin powder for dispersion in a base resin with a specific SP value.

[0035] 2. Molded article The molded article according to one embodiment of the present invention may have the above-mentioned resin particles and base resin, but is not particularly limited. For example, the resin particles may be attached to or partially embedded in the surface of the molded article as an antiblocking agent, etc., or they may be dispersed inside the molded article in a particle shape as a filler, modifier, light diffusing material, shock-absorbing material, etc. Also, for example, the resin particles may be deformed into a substantially spherical shape during the molding process, or the surface portion of the resin particles may melt and fuse with the base resin.

[0036] 2.1 Base resin The base resin is not particularly limited, but it may be a thermoplastic resin. The base resin has an SP value of 8.0 to 18.0 (cal / cm³). ３ ) １／２It is preferable that the value be 100%, more preferably 8.2 to 16.0, and even more preferably 8.4 to 14.0. For example, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0 (cal / cm ３ ) １／２ And it may be within the range of any two of the numerical values ​​exemplified here.

[0037] Examples of base resins include polycarbonate (SP value 9.9), polyester (e.g., polyethylene terephthalate, SP value 10.7), acrylic resin (polymethyl methacrylate, SP value 9.5), and ABS resin (SP value 10.7). Note that the SP value may differ depending on the structure, composition, molecular weight, etc. Furthermore, the absolute difference in SP value between the base resin and the chain transfer agent is preferably 0 to 6.8, more preferably 0 to 4.5, and for example, 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, and 6.8, and may be within the range of any two of the values ​​exemplified here. The resin particles and resin powder according to one embodiment of the present invention can be resin particles or resin powder for dispersion in the base resin having the above SP value.

[0038] In the molded article according to one embodiment of the present invention, the content of the resin particles relative to 100 parts by mass of the base resin can be, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 parts by mass, and may be within the range of any two of the values ​​exemplified herein.

[0039] A molded article according to one embodiment of the present invention contains resin particles of uniform particle size, and such resin particles are uniformly dispersed in the molded article, resulting in fewer defects and the ability to exhibit desired optical properties, mechanical properties, and other performance characteristics. Furthermore, because the molded article according to one embodiment of the present invention has a structure in which fine and coarse particles are few and uniformly dispersed resin powder of uniform particle size is present, when it is melted or dissolved and remolded, the resin particles melt easily, and even if some do not melt, the remaining resin particles are uniformly dispersed in the base resin, resulting in excellent recyclability, and thus it can be used for recycling.

[0040] 3. Method for Producing Resin Particles The method for producing resin particles and resin powder according to the present invention is not particularly limited. A method for producing resin particles and resin powder according to one embodiment of the present invention includes a polymerization step, in which the SP value by the Fedors method is 9.0 to 20.0 (cal / cm³). ３ ) １／２ A polymer can be obtained by polymerizing the starting monomers in a solvent containing a chain transfer agent.

[0041] The polymerization method is not particularly limited, but examples include suspension polymerization, seed polymerization, swollen seed polymerization, seed emulsion polymerization, emulsion polymerization, soap-free polymerization, miniemulsion polymerization, microemulsion polymerization, solution polymerization, and dispersion polymerization. Among these, seed polymerization, emulsion polymerization, soap-free polymerization, and dispersion polymerization are preferred because they make it easy to obtain resin particles with uniform particle size.

[0042] In the polymerization process, the SP value is 9.0 to 20.0 (cal / cm²). ３ ) １／２ A chain transfer agent is used. The SP value is 9.0 to 20.0 (cal / cm³). ３ ) １／２ The range is 9.2 to 15.0 (cal / cm³). ３ ) １／２ Preferably, 9.5 to 11.0 (cal / cm³) ３ ) １／２The SP values ​​are, for example, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0, 18.5, 19.0, 19.5, 20.0 (cal / cm³). ３ ) １／２ The values ​​may be within the range of any two of the values ​​exemplified here. Specific examples of chain transfer agents are as described above.

[0043] The amount of chain transfer agent used is not particularly limited, but is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass, per 100 parts by mass of raw material monomer. The amount of chain transfer agent used is, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, and 10.0 parts by mass per 100 parts by mass of raw material monomer, and may be within the range of any two of the values ​​exemplified here. When the amount of chain transfer agent used is within the above range, it is preferable because the particle size is more uniform in the polymerization process, resulting in excellent productivity and good dispersibility in the base resin.

[0044] In the polymerization step according to one embodiment of the present invention, a chain transfer agent whose SP value is outside the above range can also be used in combination. The amount of chain transfer agent whose SP value is within the above range relative to 100% by mass of the chain transfer agent used in the polymerization step is, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100% by mass, and may be within the range of any two of the values ​​exemplified here.

[0045] Examples of raw material monomers include radical polymerizable monomers. The SP values ​​of the raw material monomers are 8.0 to 18.0 (cal / cm³). ３ ) １／２The SP values ​​of the raw material monomers are, for example, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0 (cal / cm³). ３ ) １／２ And it may be within the range of any two of the numerical values ​​exemplified here.

[0046] The raw material monomer preferably contains at least one of (meth)acrylic monomers and styrene monomers. The (meth)acrylic monomers and styrene monomers are as described above. The raw material monomer may also contain polyfunctional monomers, as described above.

[0047] The amount of (meth)acrylic monomer and styrene monomer added per 100 parts by mass of raw material monomer is, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 parts by mass, and may be within the range of any two of the values ​​exemplified here. Similarly, the amount of (meth)acrylic monomer added per 100 parts by mass of raw material monomer is, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 parts by mass, and may be within the range of any two of the values ​​exemplified here. The content of monomer units other than (meth)acrylic monomer and styrene monomer per 100 parts by mass of raw material monomer is, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 parts by mass, and may be within the range of any two of the values ​​exemplified here. The amount of polyfunctional monomer added per 100 parts by mass of raw material monomer is, for example, 0, 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, or 0.010 parts by mass, and may be within the range of any two of the values ​​exemplified here.

[0048] As the solvent, an aqueous solvent is preferred. Examples of aqueous solvents include water and mixtures of water and hydrophilic organic solvents. Examples of water include purified water (e.g., deionized water, distilled water), groundwater, and tap water. Examples of hydrophilic organic solvents include lower alcohols such as methanol, ethanol, and isopropanol; polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, diethylene glycol, and triethylene glycol; cellosolves such as methyl cellosolve and ethyl cellosolve; ketones such as acetone; ethers such as tetrahydrofuran; and esters such as methyl formate. Hydrophilic organic solvents may be used alone or in combination of two or more.

[0049] The SP value of the solvent is 10.0 to 25.0 (cal / cm³). ３ ) １／２ This is possible, with 14.0 to 24.5 being preferred, and 18.0 to 24.0 being more preferred. For example, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0, 18.5, 19.0, 19.5, 20.0, 20.5, 21.0, 21.5, 22.0, 22.5, 23.0, 23.5, 24.0, 24.5, 25.0 (cal / cm ３ ) １／２ The values ​​may be within the range of any two of the values ​​exemplified here. Furthermore, the absolute difference in SP value between the solvent and the chain transfer agent is preferably 0 to 15.3, more preferably 0 to 14.5, for example, 0, 3.0, 6.0, 9.0, 12.0, 15.0, 15.3, and may be within the range of any two of the values ​​exemplified here.

[0050] In the polymerization process, initiators can be used, and emulsifiers can also be used. Examples of initiators include persulfates such as potassium persulfate and ammonium persulfate; peroxides such as benzoyl peroxide and lauryl peroxide; and azo compounds such as azobisisobutyronitrile. Polymerization initiators may be used alone or in combination of two or more. The amount of polymerization initiator used can be 0.1 to 10 parts by mass per 100 parts by mass of the raw material monomer.

[0051] Examples of emulsifiers include quaternary ammonium salts such as lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, cetyltrimethylammonium chloride, and alkylbenzyldimethylammonium chloride; alkyl sulfonates such as sodium dodecylsulfonate; alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate; alpha sulfone fatty acid ester salts such as sodium 1-methyl 2-sulfotetradecanoate; polyethylene glycol alkylaryl ethers such as polyethylene glycol nonylphenyl ether; polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether; polyoxyethylene polycyclic phenyl ethers, allyl ethers, and their sulfate ester salts. Among these, alkylbenzenesulfonates, polyoxyethylene polycyclic phenyl ethers, allyl ethers, and their sulfate ester salts are preferred. The emulsifier may be used alone or in combination of two or more. The amount of emulsifier used can be 0.01 to 20 parts by mass per 100 parts by mass of the raw material monomer.

[0052] The polymerization temperature can be 40 to 100°C, preferably 70 to 90°C, and the polymerization time can be 0.5 to 24 hours, preferably 0.5 to 10 hours.

[0053] A manufacturing method according to one embodiment of the present invention may include a seed particle preparation step, and a polymerization step may be carried out in the presence of seed particles obtained in the seed particle preparation step to grow the seed particles and obtain resin particles.

[0054] In the seed particle preparation step, seed particles can be obtained by polymerizing the raw material monomers in a solvent using an initiator. The types and amounts of raw material monomers, initiators, solvents, emulsifiers, and chain transfer agents used in the seed particle preparation step can be as described above. Chain transfer agents do not need to be used in the seed particle preparation step. The number-average particle diameter D of the seed particles is not particularly limited, but can be 0.01 to 100 μm. The number-average particle diameter D of the seed particles can be, for example, 0.01, 0.05, 0.1, 0.5, 1, 5, 10, 50, or 100 μm, and may be within the range of any two of the values ​​exemplified here.

[0055] When the method for producing resin particles according to one embodiment of the present invention includes a seed particle preparation step, in the subsequent polymerization step, the seed particles and the SP value by the Fedors method are 9.0 to 20.0 (cal / cm³). ３ ) １／２ A polymer can be obtained by polymerizing the raw material monomers in a solvent containing a chain transfer agent. Note that the polymerization step according to one embodiment of the present invention does not necessarily include a seed particle preparation step.

[0056] A method for producing resin particles according to one embodiment of the present invention may include a crushing step for crushing the resin particles obtained in the polymerization step. The crushing step can employ known methods, such as using a jet mill.

[0057] 4. Method for Manufacturing a Molded Article The method for manufacturing a molded article according to one embodiment of the present invention is not particularly limited and may include a molding step of molding raw materials, including a base resin and resin particles, into a desired shape. Known methods can be used for the molding step, and for example, mixing and molding can be performed using an injection molding machine. In the molding step, the base resin and resin particles can be put into the molding machine at the same time, or the base resin can be heated and melted first, and then the resin particles can be added to the molten base resin and dispersed. The types of base resin and resin particles are as described above, and it is preferable to adjust the amount of resin particles added so that the content of resin particles relative to the base resin is as described above. The molding temperature is not particularly limited, but for example, it may be 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300°C, and may be within the range of any two of the values ​​exemplified here.

[0058] 5. Method for Manufacturing a Second Molded Article According to the method for manufacturing a second molded article according to one embodiment of the present invention, the above-mentioned molded article (first molded article) can be used as a raw material, and another molded article (second molded article) can be obtained by recycling the above-mentioned molded article (first molded article). The recycling method is not particularly limited, and at least a portion of the base resin in the first molded article may be melted by heating or dissolved in an organic solvent. Furthermore, after melting or dissolving, it may be remolded into a second molded article of the same or different type.

[0059] A method for manufacturing a second molded article according to one embodiment of the present invention can be a method for manufacturing a second molded article from raw materials including a first molded article. Here, the first molded article can be a molded article containing the resin particles and the base resin. The manufacturing method can include a melting step, in which the raw materials are heated to 100 to 300°C to melt at least a portion of the base resin in the first molded article. The raw materials can include one or more of the above molded articles, and can also include other materials (e.g., base resin, resin particles, another molded article). The raw materials can also be composed of the first molded article. The heating temperature is not particularly limited, but is preferably 100 to 300°C, more preferably 120 to 290°C, and even more preferably 140 to 280°C. The heating temperature can be, for example, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, or 300°C, and may be within the range of any two of the values ​​exemplified here. It is preferable that the heating temperature is within the above range because the resin particles melt easily into the base resin, resulting in excellent recyclability and suppression of deterioration of the base resin by suppressing excessive thermal load. The molded article according to one embodiment of the present invention is not limited as long as it contains the above resin particles and base resin, and includes the first molded article and the second molded article.

[0060] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0061] [Example 1] <Preparation of Seed Particles> 100 parts by mass of methyl methacrylate (MMA) and 300 parts by mass of water were placed in a reaction vessel, and the temperature of the reaction solution was raised to 80°C while stirring under nitrogen purge. Next, 0.5 parts by mass of potassium persulfate was added as a polymerization initiator, and the polymerization reaction was carried out at 80°C for about 6 hours to obtain a dispersion (A) containing seed particles with a number average particle size D of 0.4 μm. The method for measuring the number average particle size D of the seed particles was the same as the method for measuring the number average particle size D of the resin particles described later.

[0062] <Production of Resin Particles> In a reaction vessel, 93 parts by mass of MMA, 1.5 parts by mass of 2-ethylhexyl-3-mercaptopropionate (EHMP) as a chain transfer agent, 2 parts by mass of benzoyl peroxide (BPO) as a polymerization initiator, 0.5 parts by mass of sodium dodecylbenzenesulfonate (DBSNa) as an emulsifier, 200 parts by mass of water, and 0.05 parts by mass of sodium nitrite were added and mixed. Next, 7 parts by mass of the solid content of the seed particles of the above dispersion (A) were added, and after stirring at 30°C for 30 minutes, the polymerization reaction was carried out at 80°C for 90 minutes. After that, the reaction solution was processed with a 400 mesh to obtain a dispersion (B) containing resin particles with a number average particle size D of 0.96 μm. The obtained dispersion (B) was dried in a spray dryer and crushed in a jet mill to obtain resin particles. Here, the obtained polymer (resin particles) has a structure (CH) derived from 2-ethylhexyl-3-mercaptopropionate (EHMP). ３ (CH ２ ) 3CH (C ２ H ５ )CH ２ OCOCH ２ CH ２ It had S-).

[0063] <Acetone-Insoluble Fraction> Approximately 1 g of the obtained resin particles was taken and immersed in 100 g of acetone, then shaken at 50°C for 5 hours. After that, the mixture was centrifuged at 10,000 rpm for 60 minutes using a centrifuge, the supernatant was removed, and the mixture was dried in an oven at 80°C for 3 hours. The weight of the insoluble fraction (W2) after drying was calculated using the following formula: W2 / W1 × 100 (%)

[0064] <Molecular Weight of Acetone-Soluble Components> Using the supernatant after centrifugation in the <Acetone-Insoluble Components> procedure described above, the Mw in terms of standard polystyrene equivalent was determined by GPC under the following conditions: • Measuring device: HLC-8220GPC (Tosoh Corporation) • GPC column configuration: The following five-column system (all from Tosoh Corporation): (1) TSK-GEL HXL-H (guard column) (2) TSK-GEL G7000HXL (3) TSK-GEL GMHXL (4) TSK-GEL GMHXL (5) TSK-GEL G2500HXL • Sample concentration: Diluted with tetrahydrofuran to 1.0 mg / cm³ • Mobile phase solvent: Tetrahydrofuran • Flow rate: 1.0 cm ３ / min Column temperature: 40°C

[0065] <Particle Size> The obtained resin particles were fixed to a sample stage with conductive double-sided carbon tape attached to it to prepare an observation sample. Next, the observation sample was photographed using an SEM (S-4300 manufactured by Hitachi High-Technologies Corporation) under the following conditions: magnification: 10,000x, acceleration voltage: 1kV, emission current: 10μA, working distance: 5mm, signal: SE. Subsequently, using image analysis software (FineView manufactured by Astron Corporation), the equivalent circular diameter of 500 primary particles randomly selected from the obtained images was measured, and the number-average particle size distribution D, the proportion of fine particles (particles with a particle size of 0.5D or less), and the proportion of coarse particles (particles with a particle size of 1.5D or more) were calculated from the particle size distribution based on the number of particles.

[0066] <Manufacturing of Molded Articles> A sheet-like molded article with a thickness of 1 mm was produced by injection molding a raw material prepared so that the amount of resin particles was 10 parts by mass per 100 parts by mass of polyethylene terephthalate, at a temperature of 280°C using an injection molding machine.

[0067] <Dispersibility> The degree of dispersion of resin particles was evaluated according to the following criteria by observing a 1 mm x 1 mm area of ​​the obtained molded body at 1000x magnification using an optical microscope (Olympus BX53M). ○: Particles are uniformly monodisperse. △: A small amount of aggregated particles are observed, but this does not pose a problem for actual use. ×: Many aggregated particles are observed.

[0068] <Manufacturing of remolded product> After cutting the obtained molded product into chips, the mixture was kneaded at 280°C for 20 minutes using an injection molding machine to produce a sheet-like remolded product with a thickness of 1 mm.

[0069] <Recyclability> The remolded material obtained was observed visually, and then a 1 mm x 1 mm area was observed under 1000x magnification using an optical microscope (Olympus BX53M) and evaluated according to the following criteria. ○: Appears transparent under visual observation, and no resin particles or traces thereof are visible under magnification. △: Appears transparent under visual observation, and slight traces of resin particles are visible under magnification. ×: Appears cloudy under visual observation, and many resin particles or traces thereof are visible under magnification.

[0070] <Dispersibility> Among the remolded articles obtained, those with a recyclability rating of △ or ×, and in which resin particles or traces thereof were confirmed upon magnified observation, were evaluated for dispersibility in the same manner as the molded articles. A 1 mm × 1 mm area was observed using an optical microscope at 1000x magnification, and the degree of dispersion of resin particles was evaluated according to the following criteria: ○: Particles are uniformly monodisperse △: A small amount of aggregated particles are observed, but not to an extent that would cause problems in actual use ×: Many aggregated particles are observed -: No evaluation (no resin particles or traces thereof are observed in the remolded article)

[0071] [Examples 2-7] Resin particles were obtained in the same manner as in Example 1, except that the components used and their proportions were changed as shown in Table 1. The evaluation results are also shown in Table 1. [Example 8] 100 parts by mass of MMA, 1.3 parts by mass of methoxybutyl-β-mercaptopropionate (MBMP) as a chain transfer agent, and 200 parts by mass of water were placed in a reaction vessel, and the temperature of the reaction solution was raised to 80°C while stirring under nitrogen purging. Next, 0.3 parts by mass of potassium persulfate was added as a polymerization initiator, and the polymerization reaction was carried out at 80°C for about 6 hours to obtain a dispersion (C) containing particles with a number average particle size D of 0.55 μm. The obtained dispersion (C) was dried in a spray dryer and crushed in a jet mill to obtain resin particles. The evaluation results are also shown in Table 1. [Example 9] Resin particles were obtained in the same manner as in Example 8, except that the components used and their proportions were changed as shown in Table 1. The evaluation results are also shown in Table 1. [Comparative Examples 1-4] Resin particles were obtained in the same manner as in Example 1, except that the components used and their proportions were changed as shown in Table 1. The evaluation results are shown in Table 1 as well. [Comparative Example 5] Resin particles were obtained in the same manner as in Example 8, except that the components used and their proportions were changed as shown in Table 1. The evaluation results are shown in Table 1 as well.

[0072]

[0073] The components used in the examples and comparative examples are as follows: MMA: Methyl methacrylate (SP value: 9.4) HEMA: 2-Hydroxyethyl methacrylate (SP value: 12.1) EGDMA: Ethylene glycol dimethacrylate (SP value: 9.8) EHMP: 2-Ethylhexyl-3-mercaptopropionate (SP value: 9.2) MBMP: Methoxybutyl-β-mercaptopropionate (SP value: 10.0) BMPA: 3-Mercaptopropionic acid (SP value: 11.8) nDM: n-Dodecyl mercaptan (SP value: 8.6) nOM: n-Octyl mercaptan (SP value: 8.6) KPS: Potassium persulfate polyethylene terephthalate (SP value: 10.7)

[0074] As shown in Table 1, the resin particles of Examples 1 to 9, which contained polymers having a chain transfer agent-derived structure with an SP value of 9 to 20, exhibited excellent dispersibility. Furthermore, the resin powders obtained in Examples 1 to 9 had a low total content of fine and coarse particles, resulting in resin powders with uniform particle size. In particular, the resin particles of Examples 1 to 5 and 7 to 9, which had an acetone-insoluble content of 10% or less, also exhibited excellent recyclability and are useful from an environmental perspective.

Claims

1. Resin particles, wherein the resin particles have an SP value of 9.0 to 20.0 (cal / cm³) according to the Fedors method. ３ ) １／２ Resin particles containing a polymer having a structure derived from a chain transfer agent.

2. Resin particles according to claim 1, wherein the acetone-insoluble content is 10% or less.

3. Resin particles according to claim 1 or claim 2, wherein the weight-average molecular weight of the acetone-soluble portion is 5,000 to 200,000.

4. A resin powder comprising resin particles according to claim 1 or claim 2, wherein, when the particle size distribution of the resin powder is obtained based on the number of particles with an equivalent circle diameter by image analysis using a scanning electron microscope, and the number-average particle diameter is D, the total content of particles with a particle diameter of 0.5D or less and particles with a particle diameter of 1.5D or more is 10.0% or less.

5. A molded article having resin particles and a base resin as described in claim 1 or claim 2.

6. A method for producing resin particles, comprising a polymerization step, wherein the SP value obtained by the Fedors method is 9.0 to 20.0 (cal / cm³). ３ ) １／２ A method for producing resin particles, comprising polymerizing raw material monomers in a solvent containing a chain transfer agent to obtain a polymer.

7. A method for manufacturing a second molded body from raw materials including a first molded body, wherein the first molded body is the molded body described in claim 5, and the manufacturing method includes a melting step, in which the raw materials are heated to 100 to 300°C to melt at least a portion of the base resin in the first molded body.

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