JP2008266583A - Particles of carbon-containing modified polystyrene resin, expandable particles of carbon-containing modified polystyrene resin, expanded particles of carbon-containing modified polystyrene resin, foam-molded article of carbon-containing modified polystyrene resin, and process for producing them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foam-molded article of a carbon-containing modified polystyrene resin that is improved in defects possessed by both a foam-molded article of a polystyrene resin and a foam-molded article of a polypropylene resin and is excellent in chemical resistance, heat resistance, foam moldability and the like. <P>SOLUTION: Carbon-containing modified polystyrene resin particles contain a carbon-containing polypropylene resin and contain a polystyrene resin in an amount of not less than 100 pts.mass to less than 400 pts.mass based on 100 pts.mass of the carbon-containing polypropylene resin in which the proportion of the polystyrene resin in the central part of the particle, as calculated from the ratio of the absorbance at 698 cm<SP>-1</SP>to the absorbance at 1,376 cm<SP>-1</SP>(D<SB>698</SB>/D<SB>1376</SB>) measured in an infrared absorption spectrum of the central part of the particle when determined by infrared spectroscopic analysis by the ATR method, is 1.2 or more times the proportion of the polystyrene resin in the whole particle. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a carbon-containing modified polystyrene resin particle obtained by polymerizing styrene with a carbon-containing polypropylene resin as a core, and a foamable carbon-containing modified polystyrene resin impregnated with a foaming agent. Particles, carbon-containing modified polystyrene resin foam particles obtained by pre-foaming the particles, carbon-containing modified polystyrene resin foam moldings obtained by in-mold foam molding of the foam particles, and production thereof Regarding the method.

Conventionally, polystyrene resin foam moldings obtained by filling polystyrene resin pre-expanded particles in a mold and heating and foaming are excellent in rigidity, heat insulation, light weight, water resistance and foam moldability. Are known. Therefore, this foaming molding is widely used as a buffer material or a heat insulating material for building materials. However, this foam molded article has a problem that it is inferior in chemical resistance and impact resistance.
On the other hand, it is known that a foam-molded article made of polypropylene resin is excellent in chemical resistance and impact resistance. Therefore, this foaming molding is used for automobile-related parts. However, since the polypropylene-based resin is inferior in foaming gas retention, it is necessary to precisely control the foam molding conditions, and there is a problem that the manufacturing cost is high. In addition, there is a problem that the rigidity is inferior to that of the polystyrene-based resin foam molding.
In order to solve the problems of the polystyrene resin and the polypropylene resin, a foam molding in which a polystyrene resin having a good rigidity and foam moldability and a polypropylene resin having a good chemical resistance and impact resistance are combined. A body has been proposed (see, for example, Patent Documents 1 and 2).

  Patent Document 1 discloses that a vinyl monomer component (b) is used with respect to 100 parts by mass of polypropylene (a) for the purpose of providing a foamed molded article having practical impact resistance, rigidity, surface properties, and the like. An aqueous suspension containing 0.01 to 10 parts by mass of a radical polymerization initiator (c) with respect to 1 to 500 parts by mass and 100 parts by mass of the vinyl monomer component (b) The vinyl monomer component (b) is heated under conditions that do not polymerize by itself, and then the vinyl monomer component (b) is impregnated into the polypropylene (a). Pre-expanded particles comprising a modified polypropylene resin composition obtained by heating the crystalline part of the polypropylene (a) to a temperature higher than or equal to a temperature at which melting starts substantially and polymerizing the vinyl monomer component (b) Is disclosed.

  In Patent Document 2, 100 parts by mass of propylene-based resin pellets or powder containing 1 to 10% by mass of an ethylene component is dispersed in an aqueous suspension, and about 30 to 30% of a styrenic monomer is contained in the suspension. A method of obtaining spherical polypropylene resin particles characterized by adding 150 parts by mass, heat-treating at a temperature of 130 ° C. or higher, and then performing polymerization in the presence of a polymerization catalyst is disclosed.

In addition, depending on the use of the foamed molded product, it may be desired to be colored in black, and carbon is known as a black colorant.
However, this carbon is known to cause polymerization delay or incomplete polymerization of the styrene monomer. In response to this problem, a method of obtaining black styrene-modified polyethylene resin expanded particles by using a polymerization initiator whose main component is a polymerization initiator that generates tertiary alkoxy radicals is disclosed (for example, patents). References 3 and 4).
In Patent Document 3, as a polymerization initiator, dicumyl peroxide, n-butyl-4,4-bis (t-butyl peroxide) bahalate, 1,1-bis (t-butylperoxy) -3,3 Specific examples thereof include 5-trimethylcyclohexane and the like.

In Patent Document 4, as a polymerization initiator, a first polymerization initiator that generates a tertiary alkoxy radical and has a 10-hour half-life temperature of 100 ° C. or less, and 2,2-bis (t-butylperoxy) It is disclosed that a second polymerization initiator composed of butane is used in combination. As the first polymerization initiator, t-butylperoxy-2-ethylhexanoate, t-amylperoxyl-2-ethylhexanoate, t-butylperoxyisobutyrate, 1,1,3, 3-tetramethylbutylperoxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxy3,5,5-trimethylhexanoate, di-t-butylperoxyhexahydroterephthalate, etc. Are specifically mentioned.
JP-A-9-194623 Japanese Patent Publication No. 61-9432 Japanese Patent Publication No. 5-54854 JP 2006-111862 A

  However, the modified resin particles obtained by the methods disclosed in Patent Documents 1 and 2 contain a large amount of polypropylene resin particularly in the vicinity of the surface portion (that is, a large amount of polystyrene resin exists in the center of the particle). It was difficult to achieve sufficient chemical resistance. Moreover, the foam-molded article formed by foaming using the modified resin particles obtained by these methods did not have sufficient heat resistance.

Moreover, even if the polymerization initiators disclosed in Patent Documents 3 and 4 are used, it is difficult to sufficiently complete the polymerization of the styrenic monomer, and as a result, a foamed molded article having the desired blackness is obtained. There was no. In particular, in the case of applications such as members in automobile interiors, color is important, and modified resin particles that can provide a beautiful foamed molded article have been desired.
Furthermore, in the styrene-modified polyethylene resin expanded particles, if a large amount of polystyrene is present on the particle surface, sufficient blackness cannot be obtained even if carbon is added. The polyethylene resin expanded particles have a high blackness due to a large amount of polystyrene on the particle surface.

  The present invention has been made in view of the above circumstances, and has improved the disadvantages of both polystyrene-based resin foam molded products and polypropylene-based resin foam molded products, and has improved carbon-containing modification excellent in chemical resistance, heat resistance, foam moldability, and the like. An object is to provide a high-quality polystyrene-based resin foam molded article.

In order to achieve the above object, the present invention contains a carbon-containing polypropylene resin,
Obtained from an infrared absorption spectrum of a particle center part containing 100 parts by mass or more and less than 400 parts by mass of a polystyrene resin with respect to 100 parts by mass of the carbon-containing polypropylene resin and measured by ATR infrared spectroscopy. Carbon content in which the polystyrene resin ratio at the center of the particle calculated from the absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ) at ₆₉₈ cm ⁻¹ and 1376 cm ⁻¹ is 1.2 times or more of the polystyrene resin ratio of the entire particle Modified polystyrene resin particles are provided.

  In the carbon-containing modified polystyrene resin particles of the present invention, the flame retardant is preferably contained in an amount of 1.5 parts by mass or more and less than 6 parts by mass with respect to 100 parts by mass of the carbon-containing polypropylene resin.

In the carbon-containing modified polystyrene resin particles of the present invention, the absorbance ratio at 698cm ^-1 and 1376cm ^-1 obtained from an infrared absorption spectrum of the measured particle surface by ATR method infrared spectroscopy _{(D 698 /} D ₁₃₇₆₎ is A range of 0.1 to 2.5 is preferable.

  In the carbon-containing modified polystyrene resin particles of the present invention, the average particle diameter of carbon in the carbon-containing polypropylene resin is 15 nm to 35 nm before being contained in the polypropylene resin, and is 1 to 8% by mass. It is preferable to include carbon particles.

  In the carbon-containing modified polystyrene resin particles of the present invention, the flame retardant is preferably tri (2,3-dibromopropyl) isocyanate.

  The present invention also provides expandable carbon-containing modified polystyrene resin particles obtained by impregnating the carbon-containing modified polystyrene resin particles with a foaming agent.

  The present invention also provides carbon-containing modified polystyrene resin expanded particles obtained by pre-expanding the expandable carbon-containing modified polystyrene resin particles.

  In addition, the present invention provides a carbon-containing modified polystyrene resin foam molded article obtained by filling the above-mentioned carbon-containing modified polystyrene resin foamed particles in a mold and foam-molding the mold.

  In the carbon-containing modified polystyrene resin foam molded article of the present invention, the shrinkage ratio in the dimensional change measurement under the condition of 80 ° C. based on JIS K 6767 is 1.0% or less, and the expansion ratio is 20 to 40 times. A range is preferable.

The present invention also includes a step of dispersing 100 parts by mass of carbon-containing polypropylene resin particles, 100 parts by mass or more and less than 400 parts by mass of a styrene monomer, and a polymerization initiator in an aqueous suspension containing a dispersant. When,
Heating the obtained dispersion to a temperature at which the styrenic monomer is not substantially polymerized to impregnate the carbon-containing polypropylene resin particles with the styrenic monomer;
A step of performing the first polymerization of the styrene monomer at a temperature of (T-10) ° C. to (T + 20) ° C. when the melting point of the carbon-containing polypropylene resin particles is T ° C .;
Subsequent to the first polymerization step, a styrene monomer and a polymerization initiator are added, and the temperature is set to (T-25) ° C. to (T + 10) ° C., thereby the carbon-containing polypropylene resin. There is provided a method for producing carbon-containing modified polystyrene resin particles, comprising the steps of impregnating the particles with the styrene monomer and performing a second polymerization.

  The method for producing carbon-containing modified polystyrene resin particles of the present invention may include a step of impregnating the resin particles during the second polymerization or the resin particles after the completion of the second polymerization with a flame retardant. preferable.

  In the method for producing carbon-containing modified polystyrene resin particles of the present invention, the carbon-containing polypropylene resin particles preferably have a melting point of 120 ° C to 145 ° C.

  In the method for producing carbon-containing modified polystyrene resin particles of the present invention, the polypropylene resin in the carbon-containing polypropylene resin is preferably a propylene-ethylene copolymer.

  The present invention also relates to expandable carbon-containing modified polystyrene resin particles obtained by impregnating a carbon-containing modified polystyrene resin particle obtained by the production method with a foaming agent to obtain expandable carbon-containing modified polystyrene resin particles. A manufacturing method is provided.

  In addition, the present invention provides a method for producing carbon-containing modified polystyrene resin expanded particles obtained by heating and pre-expanding expandable carbon-containing modified polystyrene resin particles obtained by the above production method to obtain expanded particles.

  Further, the present invention provides a carbon in which the carbon-containing modified polystyrene resin expanded particles obtained by the above production method are filled in a cavity of a mold, then subjected to in-mold foam molding, and then the molded body is released from the mold. A method for producing a modified polystyrene-based resin foam molded article is provided.

The carbon-containing modified polystyrene resin particles of the present invention contain a carbon-containing polypropylene resin, and contain 100 parts by mass or more and less than 400 parts by mass of a polystyrene resin with respect to 100 parts by mass of the carbon-containing polypropylene resin. and, ATR method infrared spectroscopy absorbance ratio at 698cm ^-1 and 1376cm ^-1 obtained from an infrared absorption spectrum of the particles heart measured by analysis _{(D 698 /} D ₁₃₇₆₎ particles center of polystyrene polymer that is obtained by the Since the ratio is 1.2 times or more with respect to the polystyrene resin ratio of the whole particle, the expandable modified polystyrene resin particles obtained by impregnating the carbon-containing modified polystyrene resin particles with a foaming agent are used. After pre-foaming, a car obtained by filling the pre-foamed particles into a mold and foam-molding The modified polystyrene-based resin foam-molded product contains the advantages of each of the polystyrene-based resin foam and the polypropylene-based resin foam molded product, and is excellent in rigidity, foam moldability, chemical resistance, heat resistance and blackness. It becomes a foamed molded product. Therefore, according to the present invention, it is possible to provide carbon-containing modified polystyrene resin particles suitable for the production of a foamed molded article having such excellent physical properties.
Since the expandable carbon-containing modified polystyrene resin particles of the present invention are obtained by impregnating the above-mentioned carbon-containing modified polystyrene resin particles with a foaming agent, rigidity, foam moldability, chemical resistance, heat resistance and black It is possible to provide expandable carbon-containing modified polystyrene resin particles suitable for production of a foam molded article excellent in degree.
Since the carbon-containing modified polystyrene resin expanded particles of the present invention are prepared by pre-expanding the above-described expandable carbon-containing modified polystyrene resin particles, rigidity, foam moldability, chemical resistance, heat resistance and blackness It is possible to provide expanded polystyrene-containing resin particles containing carbon that are suitable for the production of an expanded molded article having excellent quality.
Since the carbon-containing modified polystyrene resin foam molded article of the present invention is obtained by filling the above-mentioned carbon-containing modified polystyrene resin foamed foam into a mold and performing foam molding, rigidity, foam moldability, chemical resistance, heat resistance In addition, it is possible to provide a carbon-containing modified polystyrene resin foam molded article having excellent blackness.

In the method for producing carbon-containing modified polystyrene resin particles of the present invention, in an aqueous suspension containing a dispersant, 100 parts by mass of carbon-containing polypropylene resin particles and 100 parts by mass or more and less than 400 parts by mass of a styrene monomer. And the polymerization initiator are dispersed, and the resulting dispersion is heated to a temperature at which the styrene monomer is not substantially polymerized to impregnate the carbon-containing polypropylene resin particles with the styrene monomer. Then, when the melting point of the carbon-containing polypropylene resin particles is T ° C., the first polymerization of the styrene monomer is performed at a temperature of (T−10) ° C. to (T + 20) ° C. Following the second polymerization, a styrene monomer and a polymerization initiator are added, and the second polymerization of the styrene monomer is performed at a temperature of (T-25) ° C. to (T + 10) ° C. Possibly , ATR method infrared spectroscopy polystyrene type resin ratio of particles center calculated from the absorbance ratio at 698cm ^-1 and 1376cm ^-1 obtained from an infrared absorption spectrum of the measured particle center _{(D 698 /} D ₁₃₇₆₎ by However, it is possible to produce carbon-containing modified polystyrene resin particles that are 1.2 times or more of the polystyrene resin ratio of the entire particles. The obtained carbon-containing modified polystyrene resin particles are expanded by pre-expanding expandable carbon-containing modified polystyrene resin particles obtained by impregnating a foaming agent, and then filling the pre-expanded particles in a mold. When molded, the advantages of both polystyrene resin foam and polypropylene resin foam molded products are utilized to obtain foam molded products with excellent rigidity, foam moldability, chemical resistance, heat resistance and blackness. According to the production method, it is possible to provide carbon-containing modified polystyrene resin particles suitable for production of a foamed molded article having such excellent physical properties.
The method for producing expandable carbon-containing modified polystyrene resin particles of the present invention is to produce the expandable carbon-containing modified polystyrene resin particles by impregnating the above-mentioned carbon-containing modified polystyrene resin particles with a foaming agent. In addition, it is possible to provide foamable carbon-containing modified polystyrene resin particles suitable for production of a foam molded article having excellent rigidity, foam moldability, chemical resistance, heat resistance and blackness.
The method for producing expanded carbon-containing modified polystyrene-based resin particles according to the present invention is to produce expanded carbon-containing modified polystyrene-based resin particles by pre-expanding the aforementioned expandable carbon-containing modified polystyrene-based resin particles. Further, it is possible to provide a carbon-containing modified polystyrene resin foamed particle suitable for production of a foam molded article having excellent foam moldability, chemical resistance, heat resistance and blackness.
The method for producing a carbon-containing modified polystyrene resin foam molded article according to the present invention comprises filling the above-mentioned carbon-containing modified polystyrene resin foamed particles into a mold and foam-molding the carbon-containing modified polystyrene resin foam molded article. Since it is manufactured, it is possible to provide a carbon-containing modified polystyrene resin foam molded article excellent in rigidity, foam moldability, chemical resistance, heat resistance and blackness.

  The inventors of the present invention, as a result of intensive research to achieve the above object, added a styrene monomer to carbon-containing polypropylene resin particles having a specific melting point and containing a specific carbon. It was found that carbon-containing modified polystyrene resin particles in which the amount of styrene increases in the center of the particle and the amount of polypropylene resin increases in the vicinity of the particle surface can be obtained by polymerization in a specific temperature range.

  Further, the carbon-containing modified polystyrene resin particles produced in this way are pre-foamed with expandable carbon-containing modified polystyrene resin particles obtained by impregnating a foaming agent, and then the foamed particles are filled into a mold. When using in-mold foam molding, the advantages of each of polypropylene resin and polystyrene resin can be utilized to produce a carbon-containing modified polystyrene resin foam molded article excellent in foam moldability, chemical resistance and heat resistance. As a result, the present invention was completed.

The carbon-containing modified polystyrene resin particles of the present invention contain 100 parts by mass or more and less than 400 parts by mass of polystyrene resin with respect to 100 parts by mass of the carbon-containing polypropylene resin, and are measured by ATR infrared spectroscopy. polystyrene-based resin ratio of particles center calculated from the absorbance ratio at 698cm ^-1 and 1376cm ^-1 obtained from an infrared absorption spectrum of the particles center _{(D 698 /} D ₁₃₇₆₎ is the entire particle polystyrene resin ratio It is characterized by being 1.2 times or more.

  In the modified polystyrene resin particles of the present invention, the “particle center” means a portion in a range from the center of the particle to ¼ of the diameter (particle diameter) of the particle in a cross section passing through the center of the particle. For example, the particle central portion in a spherical particle having a particle diameter of 1 mm is a portion having a radius of 125 μm from the center of the particle.

  The polypropylene resin, which is one of the resin materials of the modified polystyrene resin particles of the present invention, is not particularly limited, and a resin obtained by a known polymerization method can be used, for example, propylene-ethylene copolymer Coalescence is used. This propylene-ethylene copolymer is mainly composed of a copolymer of ethylene and propylene, but may contain ethylene or another monomer that can be copolymerized with propylene in the molecule. Good. Examples of such a monomer include one or more selected from α-olefins, cyclic olefins, and diene monomers.

  In a preferred embodiment of the present invention, a polypropylene resin having a melting point in the range of 120 ° C. to 145 ° C. is used. When the melting point of the polypropylene resin is lower than 120 ° C., the heat resistance is poor, and the heat resistance of the modified polystyrene resin foam molded article produced using the modified polystyrene resin particles is lowered. On the other hand, when the melting point is higher than 145 ° C., the polymerization temperature becomes high and good polymerization cannot be performed.

In a preferred embodiment of the present invention, examples of the carbon in the carbon-containing polypropylene resin include furnace black, ketjen black, channel black, thermal black, acetylene black, graphite, and carbon fiber.
Before being included in the polypropylene resin, the carbon (raw material carbon) is preferably in the form of particles, and the average particle size of the raw material carbon is usually preferably 5 nm to 100 nm, and more preferably 15 nm to 35 nm. is there. In addition, the particle diameter of raw material carbon means an average particle diameter, and an average particle diameter is an arithmetic average by an electron microscope. The average particle size that characterizes the carbon black used in the present invention is the particle size measured and calculated with an electron micrograph of small spherical components (which have a fine crystal outline and cannot be separated) that constitute the carbon black aggregate. It is the average diameter.

In the carbon-containing modified polystyrene resin particles of the present invention, it is preferable that 1 to 8% by mass of carbon is contained in the carbon-containing modified polystyrene resin particles.
If the blending amount of carbon in the carbon-containing modified polystyrene resin particles is less than 1% by mass, the resulting foamed molded product cannot exhibit a sufficient black color, which is not preferable. On the other hand, if the amount of carbon exceeds 8% by mass, it is not preferable because not only the bulk expansion ratio of the foamed molded product obtained from the carbon-containing modified polystyrene resin particles is lowered but also the mechanical strength is lowered.

  The polypropylene resin may contain additives such as a flame retardant, a flame retardant aid, an antioxidant, an ultraviolet absorber, a pigment, and a colorant as necessary.

  In the carbon-containing modified polystyrene resin particles of the present invention, the flame retardant can be appropriately selected from an organic flame retardant and an inorganic flame retardant. For example, tri (2,3-dibromopropyl) isocyanate can be used. Can be mentioned. This flame retardant preferably contains 1.5 parts by mass or more and less than 6 parts by mass, preferably 2.0 parts by mass or more and less than 5 parts by mass with respect to 100 parts by mass of the carbon-containing polypropylene resin. Further preferred. The effect of the carbon-containing modified polystyrene resin particles of the present invention by adding a flame retardant to 1.5 parts by mass or more and less than 6 parts by mass with respect to 100 parts by mass of the carbon-containing polypropylene resin, that is, polystyrene resin foaming The advantages of each of the foam and the polypropylene resin foam molded body are utilized, without impairing the effect that a foam molded body excellent in rigidity, foam moldability, chemical resistance, heat resistance and blackness can be obtained. Flame retardancy can be imparted to the molded body.

In the carbon-containing modified polystyrene resin particles of the present invention, as the flame retardant aid, 2,3-dimethyl-2,3-diphenylbutane, 3,4-dimethyl-3,4-diphenylhexane, dicumyl peroxide 1 or 2 or more types selected from the group of organic peroxides of cumene hydroperoxide.
The flame retardant assistant is in the range of 0.1 to 3 parts by mass with respect to 100 parts by mass of the carbon-containing modified polystyrene resin particles. The compounding quantity of a preferable flame retardant adjuvant is 0.5-2.5 mass parts, and 1-2 mass parts is more preferable. When the blending amount of the flame retardant aid is less than 0.1 parts by mass, the self-extinguishing property of the foamed molded article obtained by secondary foaming of the pre-foamed particles is not preferable. On the other hand, when the blending amount of the flame retardant is more than 3 parts by mass, the change in the heating dimension of the foamed molded product obtained by secondary foaming of the pre-foamed particles is not preferable.

  In addition, in the carbon-containing modified polystyrene resin particles of the present invention, when a flame retardant and a flame retardant aid are added, it is preferable that the flame retardant and the flame retardant aid are present in a large amount on the particle surface. Good.

In the carbon-containing modified polystyrene resin particles of the present invention, the colorant may be an inorganic pigment or an organic pigment.
Examples of inorganic pigments include chromates such as chrome yellow, zinc yellow and barium yellow, ferrocyanides such as bitumen, sulfides such as cadmium yellow and cadmium red, oxides such as iron black and red husk, and ultramarine blue. And silicates such as titanium oxide.
Examples of organic pigments include azo pigments such as monoazo pigments, disazo pigments, azo lakes, condensed azo pigments, chelate azo pigments, phthalocyanine-based, anthraquinone-based, perylene-based, perinone-based, thioindigo-based, quinacridone-based, and dioxazine-based pigments. And polycyclic pigments such as isoindolinone and quinophthalone.

  Examples of the polystyrene resin, which is another resin material of the carbon-containing modified polystyrene resin particles of the present invention, include a styrene-based monomer such as styrene, α-methylstyrene, p-methylstyrene, and t-butylstyrene. Examples thereof include resins obtained by polymerizing the body. Furthermore, the polystyrene resin may be a copolymer of a styrene monomer and another monomer copolymerizable with the styrene monomer. Examples of other monomers include polyfunctional monomers such as divinylbenzene, and (meth) acrylic acid alkyl esters that do not contain a benzene ring in the structure such as butyl (meth) acrylate. . You may use these other monomers in the range which does not exceed 5 mass% substantially with respect to a polystyrene-type resin. In the present specification, styrene and a monomer copolymerizable with styrene are also referred to as a styrene monomer.

The polystyrene resin is used in an amount in the range of 100 to 400 parts by mass with respect to 100 parts by mass of the carbon-containing polypropylene resin. The compounding quantity of a preferable polystyrene-type resin is 120-300 mass parts, and 150-250 mass parts is more preferable.
When the ratio of this polystyrene resin is more than 400 parts by mass, the chemical resistance and heat resistance of the foamed molded product obtained by secondary foaming of the pre-expanded particles are not preferable. On the other hand, when the blending amount is less than 100 parts by mass, the rigidity of the foamed molded product obtained by secondary foaming of the pre-foamed particles is unfavorable.

Carbon-containing modified polystyrene resin particles of the present invention, the absorbance ratio at 698cm ^-1 and 1376cm ^-1 obtained from an infrared absorption spectrum of the particles heart measured by ATR method infrared spectroscopy _{(D 698 /} D ₁₃₇₆₎ The polystyrene resin ratio at the center of the particle calculated from the above is 1.2 times or more, preferably 1.35 times or more, particularly preferably 1.4 times or more, relative to the polystyrene resin ratio of the whole particles. It is.

  When the calculated polystyrene resin ratio in the center of the particle is 1.2 times or less than the polystyrene resin ratio of the whole particle, the gradient of the gradient of the polystyrene resin ratio decreases from the surface layer to the inside. As a result, the expansion ratio and heat resistance of the foamed molded product obtained by foaming the pre-expanded particles are unfavorable. In addition, when the polystyrene resin ratio in the center of the particle is 1.2 times or less than the polystyrene resin ratio of the entire particle, the polystyrene resin ratio on the particle surface is increased, and the pre-expanded particles are obtained by foam molding. The resulting foamed molded article cannot obtain sufficient blackness.

Further, the carbon-containing modified polystyrene resin particles of the present invention, the absorbance ratio at 698cm ^-1 and 1376cm ^-1 obtained from an infrared absorption spectrum of the measured particle surface by ATR method infrared spectroscopy _{(D 698 /} D ₁₃₇₆ ) Is preferably in the range of 0.1 to 2.5, more preferably in the range of 0.8 to 2.0, and particularly preferably in the range of 1.0 to 1.5.
The surface of the particle is a “surface layer” including a region from the surface to a depth of several μm.

  When the absorbance ratio is higher than 2.5, the ratio of the polyolefin resin on the surface of the pre-foamed particles is lowered. As a result, the chemical resistance and impact resistance of the foamed molded article obtained by foaming the pre-expanded particles are unfavorable. On the other hand, if the absorbance ratio is lower than 0.1, the dissipation of the foaming agent from the surface of the pre-foamed particles becomes significant, resulting in poor fusion between the particles during molding in the mold, and the impact resistance is reversed. This is not preferable because it tends to be lowered or the finished appearance of the foamed molded product is deteriorated due to shrinkage or the like. In addition, when pre-expanded particles are produced, the time required for the impregnation and polymerization of the styrene monomer into the polyolefin resin particles becomes longer, which is not preferable.

  Here, the ATR (Attenuated Total Reflectance) method infrared spectroscopic analysis in the present invention is an analysis method for measuring an infrared absorption spectrum by a single reflection type ATR method using total reflection absorption (Attenuated Total Reflectance). This analysis method is a method in which an ATR prism having a high refractive index is closely attached to a sample, infrared light is irradiated to the sample through the ATR prism, and the reflected light from the ATR prism is spectrally analyzed.

  ATR infrared spectroscopic analysis is not limited to organic materials such as polymer materials because the spectrum can be measured simply by bringing the sample into close contact with the ATR prism and surface analysis up to a depth of several μm is possible. It is widely used for surface analysis of various substances.

The absorbance D _{698 at 698} cm ⁻¹ obtained from the infrared absorption spectrum refers to the height of a peak appearing in the vicinity of 698 cm ⁻¹ derived from the out-of-plane bending angular vibration of the benzene ring mainly contained in the polystyrene resin.

In addition, the absorbance D _{1376 at 1376} cm ⁻¹ obtained from the infrared absorption spectrum is a peak appearing in the vicinity of 1376 cm ⁻¹ derived from the symmetrical bending vibration of CH ₃ of —C—CH ₃ hydrocarbon contained in the polypropylene resin. Say height.

As a method for obtaining the composition ratio of polystyrene resin and polypropylene resin from the absorbance ratio, a plurality of types of standard samples prepared by uniformly mixing polystyrene resin and polypropylene resin at a predetermined composition ratio are prepared as described below. Then, each standard sample is subjected to particle surface analysis by ATR infrared spectroscopy to obtain an infrared absorption spectrum. The absorbance ratio is calculated from each of the obtained infrared absorption spectra. A calibration curve is drawn by taking the composition ratio (polystyrene resin ratio (mass%) in the standard sample) on the vertical axis and the absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ) on the horizontal axis. Based on this calibration curve, the composition ratio of the polystyrene resin and the polypropylene resin in the carbon-containing modified polystyrene resin particles of the present invention can be obtained from the absorbance ratio of the carbon-containing modified polystyrene resin expanded particles of the present invention. it can.

For example, when the polypropylene resin is manufactured by Sun Allomer, trade name “PC540R”, and the polystyrene resin is polystyrene (trade name “SS142” manufactured by Sekisui Chemical Co., Ltd.), the composition ratio is obtained by using the calibration curve shown in FIG. Can know. For example, when the absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ) is 10.0, the polypropylene resin is 20.2 mass%, the polystyrene resin is 79.8 mass%, and the absorbance ratio is 15.0, the polypropylene resin. It can be calculated that the resin is 8.1% by mass and the polystyrene resin is 90.9% by mass.
The calibration curve is created by the following method.

The standard sample is obtained by the following method.
First, a total of 2 g of the polystyrene resin and the polypropylene resin are precisely weighed so that the composition ratio (polystyrene resin / polypropylene resin) becomes the following ratio.
This is heated and kneaded in a small injection molding machine under the following conditions and molded into a cylindrical shape having a diameter of 25 mm and a height of 2 mm to obtain a standard sample.
In addition, as a small-sized injection molding machine, what is sold with the brand name "CS-183" from CSI can be used, for example.

Injection molding conditions: heating temperature 200 ° C. to 250 ° C., kneading time 10 minutes Composition ratio (polystyrene resin / polypropylene resin; mass ratio):
0/10, 1/9, 2/8, 3/7, 4/6, 5/5, 6/4, 7/3, 8/2, 9/1, 10/0
The calibration curve of FIG. 1 is obtained by measuring the absorbance ratio of the standard sample of the above ratio and graphing the relationship between the polystyrene resin ratio (mass%) and the absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ).
In FIG. 1, when the polystyrene resin ratio is 40% by mass or less, the calibration curve is approximated by the following equation (1).
Y = −2.5119X ² + 22.966X (1)
In FIG. 1, when the polystyrene resin ratio is 40% by mass or more, the calibration curve is approximated by the following formula (2).
Y = 27.591Ln (X) +16.225 (2)

The carbon-containing modified polystyrene resin particles according to the present invention are efficiently provided by the method for producing carbon-containing modified polystyrene resin particles according to the present invention including the following steps (A) to (D): Moreover, it can manufacture with a sufficient yield.
(A) a step of dispersing 100 parts by mass of carbon-containing polypropylene resin particles, 100 parts by mass or more and less than 400 parts by mass of a styrene monomer, and a polymerization initiator in an aqueous suspension containing a dispersant;
(B) heating the obtained dispersion to a temperature at which the styrenic monomer is not substantially polymerized to impregnate the carbon-containing polypropylene resin particles with the styrenic monomer;
(C) When the melting point of the carbon-containing polypropylene resin particles is T ° C., the step of performing the first polymerization of the styrene monomer at a temperature of (T−10) ° C. to (T + 20) ° C.,
(D) When the styrene monomer and the polymerization initiator are added following the first polymerization step, and the melting point of the carbon-containing polypropylene resin particles is T ° C, (T-25) The step of impregnating the carbon-containing polypropylene resin particles with the styrene monomer and performing the second polymerization by setting the temperature to from C to (T + 10) ° C.
In addition, each process of (A)-(D) is a well-known polymerization method such as a suspension polymerization method or a seed polymerization method of a polystyrene resin for producing beaded polystyrene resin particles using a styrene monomer as a raw material. Although it can implement using the autoclave polymerization apparatus etc. which are used when implementing a method, the manufacturing apparatus to be used is not limited to this.

In the step (A), for example, the carbon-containing polypropylene-based resin particles are obtained by melting the carbon-containing polypropylene-based resin with an extruder and granulating the pellets by strand cutting, underwater cutting, hot cutting, or the like. It can be obtained by directly pulverizing and pelletizing resin particles. In addition, examples of the shape include a true spherical shape, an elliptical spherical shape (egg shape), a cylindrical shape, and a prismatic shape. The preferable resin particle size of the carbon-containing polypropylene resin particles is in the range of 0.5 mm to 1.5 mm, more preferably in the range of 0.6 mm to 1.0 mm.
In the step (A), as the carbon-containing polypropylene resin, those having a melting point of 120 ° C. to 145 ° C. are suitable.

  Examples of the dispersant used in the step (A) include organic dispersants such as partially saponified polyvinyl alcohol, polyacrylate, polyvinyl pyrrolidone, carboxymethyl cellulose, and methyl cellulose, magnesium pyrophosphate, calcium pyrophosphate, calcium phosphate, and carbonic acid. Examples thereof include inorganic dispersants such as calcium, magnesium phosphate, magnesium carbonate, and magnesium oxide. Of these, inorganic dispersants are preferred. When using an inorganic dispersant, it is preferable to use a surfactant in combination. Examples of such a surfactant include sodium dodecylbenzene sulfonate and α-olefin sulfonic acid sodium.

  Moreover, as a polymerization initiator, a conventionally well-known polymerization initiator widely used for polymerization of styrene monomers can be used. For example, benzoyl peroxide, lauroyl peroxide, t-amyl peroxy octoate, t-butyl peroxybenzoate, t-amyl peroxybenzoate, t-butyl peroxybivalate, t-butyl peroxyisopropyl carbonate, t- Butyl peroxyacetate, t-butylperoxy-3,3,5-trimethylcyclohexanoate, di-t-butylperoxyhexahydroterephthalate, 2,2-di-t-butylperoxybutane, dicumyl peroxide And azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile. In addition, a polymerization initiator may be used independently or may be used together.

  In addition, when adding a crosslinking agent, for example, a method of directly adding the crosslinking agent to the carbon-containing polypropylene resin, or after dissolving the crosslinking agent in a solvent, a plasticizer or a styrene monomer. The method of adding, the method of adding after dispersing a crosslinking agent in water, etc. are mentioned. Among these, a method of adding a crosslinking agent after dissolving it in a styrene monomer is preferable.

  The styrenic monomer can be continuously or intermittently added to the aqueous medium in order to impregnate the carbon-containing polypropylene resin particles. The styrenic monomer is preferably added gradually to the aqueous medium. Examples of the aqueous medium include water and a mixed medium of water and a water-soluble medium (for example, alcohol).

In the step (B), the dispersion obtained in the step (A) is heated to a temperature at which the styrene monomer is not substantially polymerized, and the carbon-containing polypropylene resin particles are impregnated with the styrene monomer. The temperature at that time is in the range of 45 ° C to 70 ° C, preferably in the range of 50 ° C to 65 ° C.
When the impregnation temperature is less than the above range, the impregnation of the styrene monomer is insufficient and a polymerized polystyrene powder is generated, which is not preferable. On the other hand, if the impregnation temperature exceeds the above range, it is not preferable because the styrene monomer is polymerized before the carbon-containing polypropylene resin particles are sufficiently impregnated.

In the steps (C) and (D), the polymerization temperature is an important factor. When the melting point of the carbon-containing polypropylene resin is T ° C., in the step (C) (first polymerization), (T The temperature range is −10) ° C. to (T + 20) ° C., and in the step (D) (second polymerization), the temperature range is (T−25) ° C. to (T + 10) ° C.
By carrying out the polymerization in the temperature range, the resin particle central part has a large amount of polystyrene resin (that is, a large amount of carbon-containing polypropylene resin in the surface layer), and as a result, the polypropylene resin and polystyrene. The carbon-containing modified polystyrene resin particles excellent in rigidity, foam moldability, chemical resistance, heat resistance, and blackness can be provided by taking advantage of each advantage of the resin.
When the polymerization temperature is lower than the above temperature range, the abundance of the polystyrene-based resin is small at the center of the obtained resin particles, and resin particles and foamed molded articles exhibiting good physical properties cannot be obtained. In addition, when the polymerization temperature is higher than the above temperature range, the polymerization starts before the styrene monomer is sufficiently impregnated with the carbon-containing polypropylene resin particles, so that the resin particles and the foam molded article exhibiting good physical properties. Cannot be obtained. In addition, an expensive polymerization facility with excellent heat resistance is required.

In addition, the step of polymerizing the styrene monomer impregnated in the carbon-containing polypropylene resin particles is divided into two steps, (C) step (first polymerization) and (D) step (second polymerization). The reason for the separation is that if a carbon-containing polypropylene resin is impregnated with many styrene monomers at once, the styrene monomer is not sufficiently impregnated in the carbon-containing polypropylene resin, and the carbon-containing polypropylene resin This is because it remains on the surface. Therefore, as in the method for producing the modified polystyrene resin particles according to the present invention, the styrene monomer is surely obtained in the step (C) by dividing into the two steps of the step (C) and the step (D). The styrene monomer is impregnated toward the center of the carbon-containing polypropylene resin in the step (D) as well.
In the step (D) (second polymerization), it is preferable to impregnate the resin particles during the second polymerization or the resin particles after the completion of the second polymerization with a flame retardant. The input temperature when adding the flame retardant is preferably in the range of 30 ° C to 90 ° C, more preferably in the range of 50 ° C to 70 ° C. After the addition, the impregnation temperature when impregnating the flame retardant is preferably in the range of t ° C. to (t + 30) ° C. when the melting point of the flame retardant is t ° C. If the temperature is lower than t ° C, the flame retardant may not be sufficiently impregnated into the carbon-containing modified polystyrene resin particles. If the temperature is higher than (t + 30) ° C, an expensive polymerization facility having excellent heat resistance is required.

After performing the polymerization in the step (D), the reaction vessel is cooled, and the formed carbon-containing modified polystyrene resin particles are separated from the aqueous medium, whereby 100 parts by mass of the carbon-containing polypropylene resin is obtained. the polystyrene resin contains less than 400 parts by mass or more to 100 parts by mass, and the absorbance ratio at 698cm ^-1 and 1376cm ^-1 obtained from an infrared absorption spectrum of the particles heart measured by ATR method infrared spectroscopy _{(D 698} / D ₁₃₇₆ ), carbon-containing modified polystyrene resin particles having a polystyrene resin ratio in the center of the particle calculated by 1.2 times or more with respect to the polystyrene resin ratio of the entire particle are obtained.

In the method for producing carbon-containing modified polystyrene resin particles of the present invention, carbon-containing polypropylene resin particles, a styrene monomer, and a polymerization initiator are dispersed in an aqueous suspension containing a dispersant. After impregnating the carbon-based polypropylene resin particles with the carbon-based monomer, the first stage polymerization is performed at a temperature of (T-25) ° C. to (T + 10) ° C. when the melting point of the polypropylene resin particles is T ° C. Then, by performing the second stage polymerization at a temperature of (T-25) ° C. to (T + 10) ° C., in the carbon-containing polypropylene resin particles, the particle center portion measured by ATR infrared spectroscopy was analyzed. absorbance ratio at 698cm ^-1 and 1376cm ^-1 obtained from an infrared absorption spectrum _{(D 698 /} D ₁₃₇₆₎ polystyrene-based resin particles center calculated from the Ratio, it is possible to produce a carbon-containing modified polystyrene resin particles is 1.2 times or more relative to the polystyrene type resin ratio of the whole particles. The resulting carbon-containing modified polystyrene resin particles are obtained by pre-expanding expandable resin particles obtained by impregnating a foaming agent, and then filling the resin particles in a mold and performing in-mold foam molding. Providing carbon-containing modified polystyrene resin particles suitable for the production of molded products with excellent rigidity, foam moldability, chemical resistance, heat resistance and blackness, taking advantage of the advantages of both resins and polystyrene resins Can do.

  The present invention provides expandable carbon-containing modified polystyrene resin particles obtained by impregnating the above-mentioned carbon-containing modified polystyrene resin particles with a foaming agent, preferably a readily volatile foaming agent, and a method for producing the same.

  Examples of the readily volatile foaming agent impregnated into the carbon-containing modified polystyrene resin particles include those having a boiling point of not more than the softening temperature of the polymer and having readily volatile properties, such as propane, n-butane, i-butane, n- Examples include pentane, i-pentane, cyclopentane, carbon dioxide, and nitrogen. These blowing agents can be used alone or in combination of two or more. The amount of the readily volatile foaming agent used is preferably in the range of 5 to 25 parts by mass with respect to 100 parts by mass of the carbon-containing modified polystyrene resin particles.

  Furthermore, you may use a foaming adjuvant with a foaming agent. Examples of such foaming aids include solvents such as toluene, xylene, ethylbenzene, cyclohexane, D-limonene, and plasticizers (high boiling solvents) such as diisobutyl adipate, diacetylated monolaurate, and palm oil. . In addition, as an addition amount of a foaming adjuvant, 0.1-2.5 mass parts is preferable with respect to 100 mass parts of carbon containing modified polystyrene resin particles.

  Further, a surface treatment agent such as a binding inhibitor, a fusion accelerator, an antistatic agent, or a spreading agent may be added to the expandable carbon-containing modified polystyrene resin particles.

  The anti-bonding agent plays a role of preventing coalescence of the pre-expanded particles when pre-expanding the expandable carbon-containing modified polystyrene resin particles. Here, coalescence means that a plurality of pre-expanded particles are united and integrated. Specific examples include talc, calcium carbonate, zinc stearate, aluminum hydroxide, ethylene bis stearamide, tricalcium phosphate, dimethylpolysiloxane, and the like.

The fusion accelerator plays a role of promoting fusion between the pre-foamed particles when the pre-foamed particles are subjected to secondary foam molding. Specific examples include stearic acid, stearic acid triglyceride, hydroxystearic acid triglyceride, sorbitan stearate, and the like.
Examples of the antistatic agent include polyoxyethylene alkylphenol ether and stearic acid monoglyceride. Examples of the spreading agent include polybutene, polyethylene glycol, and silicone oil. In addition, as for the total addition amount of the said surface treating agent, 0.01-2.0 mass parts is preferable with respect to 100 mass parts of modified polystyrene resin particles.

  The method of impregnating the carbon-containing modified polystyrene resin particles with the foaming agent can be appropriately changed according to the type of the foaming agent. For example, a method in which a foaming agent is pressed into an aqueous medium in which carbon-containing modified polystyrene resin particles are dispersed, and the foaming agent is impregnated in the resin, and the carbon-containing modified polystyrene resin particles are placed in a rotary mixer. Examples thereof include a method in which a foaming agent is pressed into the rotary mixer and the resin particles are impregnated with the foaming agent. The temperature at which the carbon-containing modified polystyrene resin particles are impregnated with the foaming agent is usually preferably 50 ° C to 140 ° C.

  Since the expandable carbon-containing modified polystyrene resin particles of the present invention are formed by impregnating the above-mentioned carbon-containing modified polystyrene resin particles with a foaming agent, the foam molding is excellent in rigidity, foam moldability and chemical resistance. Expandable carbon-containing modified polystyrene resin particles suitable for the production of a body can be provided.

The present invention provides a carbon-containing modified polystyrene resin expanded particle (hereinafter referred to as pre-expanded particle) obtained by heating and pre-expanding the above-mentioned expandable carbon-containing modified polystyrene resin particle and a method for producing the same. I will provide a.
The pre-foaming heating conditions and the apparatus used for the pre-foaming can be the same as those for the production of conventional polystyrene resin pre-foamed particles. For example, the expandable carbon-containing modified polystyrene resin particles are heated in an atmosphere having a water vapor pressure of about 0.5 to 4.0 kg / cm ² G (about 0.05 to 0.4 MPa) in a pre-foaming apparatus. Can be obtained by: The heating time is generally about 20 to 120 seconds.

The pre-expanded particles usually have a bulk density of 0.0166 to 0.2 g / cm ³ . A preferred bulk density is 0.02 to 0.1 g / cm ³ . More preferably, the bulk density is 0.025 to 0.05 g / cm ³ . If the bulk density is less than 0.0166 g / cm ³ , the strength of the foamed molded product obtained by foaming the pre-foamed particles is unfavorable. On the other hand, if the bulk density is greater than 0.2 g / cm ³ , the mass of the foamed molded article obtained by foaming the pre-foamed particles is not preferable.
Moreover, when this bulk density is expressed by a bulk foaming factor, it is bulk foaming factor (times) = 1 / bulk density (g / cm ³ ), so that this pre-expanded particle has a bulk foaming factor of 5 to 60 (times). The preferred bulk foaming factor is 10 to 50 (times), and the more preferred bulk foaming factor is 20 to 40 (times).

  The form of the pre-expanded particles is not particularly limited as long as it does not affect the subsequent in-mold foam molding. For example, a true spherical shape, an elliptical spherical shape (egg shape), a cylindrical shape, a prismatic shape and the like can be mentioned. Of these, a true spherical shape and an elliptical spherical shape, which can be easily filled into the cavity of the mold, are preferable.

  The pre-expanded particles may contain an additive. Additives include foaming nucleating agents such as talc, calcium silicate, ethylene bis-stearic acid amide, methacrylic acid ester copolymers, fillers such as synthetic or naturally produced silicon dioxide, hexabromocyclododecane, triallyl Examples include flame retardants such as isocyanurate 6 bromine compounds, plasticizers such as diisobutyl adipate, liquid paraffin, glycerin diacetomonolaurate and coconut oil, colorants such as carbon black and graphite, UV absorbers and antioxidants. .

  Since the pre-expanded particles of the present invention are prepared by pre-expanding the above-mentioned expandable carbon-containing modified polystyrene resin particles, the foam-molded product has excellent rigidity, foam moldability, chemical resistance, heat resistance and blackness. It is possible to provide pre-expanded particles suitable for the production of

The present invention provides a carbon-containing modified polystyrene resin foam molded article (hereinafter referred to as a foam molded article) obtained by in-mold foam molding of the above pre-expanded particles and a method for producing the same.
In order to make the above-mentioned pre-expanded particles into a foam-molded product, the above-mentioned pre-expanded particles are usually held for about 24 hours and aged, and then the pre-expanded particles are filled into the mold cavity and heated to heat the mold A foam-molded article having a desired shape can be obtained by foam-molding and fusing and pre-expanding particles together. This in-mold foam molding can be performed, for example, by introducing water vapor having a vapor pressure of about 0.5 to 4.5 kg / cm ² G (about 0.05 to 0.45 MPa) into the mold.

The foamed molded product of the present invention usually has a density of 0.0166 to 0.2 g / cm ³ . Preferably, the density is 0.02~0.1g / cm ^3, more preferably, the density is in the range of 0.025~0.05g / cm ^3.
If the density of the foamed molded product is less than 0.0166 g / cm ³ , the strength of the foamed molded product obtained by foaming the pre-expanded particles is not preferable. On the other hand, if the density of the foamed molded product is larger than 0.2 g / cm ³ , the mass of the foamed molded product obtained by foaming the pre-expanded particles is not preferable. In addition, when this density is expressed in terms of expansion ratio, since expansion ratio (times) = 1 / density (g / cm ³ ), this foamed molded article has a expansion ratio of 5 to 60 (times), which is preferable. The expansion ratio is 10 to 50 (times), and a more preferable expansion ratio is 20 to 40 (times).

In addition, the foamed molded article of the present invention preferably has a shrinkage ratio of the foamed molded article of 1.0% or less in the dimensional change measurement under the condition of 80 ° C. based on JIS K6767. When the shrinkage rate exceeds 1.0%, the dimensional stability is not preferable.
In addition, since shrinkage | contraction rate is so preferable that it is small, it is not necessary to provide the lower limit in particular. For example, it is desirable that the lower limit value of the shrinkage rate is zero.

  Since the foam-molded article of the present invention is obtained by in-mold foam-molding the above-mentioned carbon-containing modified polystyrene resin expanded particles, a foam-molded article excellent in rigidity, foam moldability, chemical resistance, heat resistance and blackness is obtained. Can be provided.

  The foamed molded product obtained as described above can be used for various purposes such as vehicle bumper core materials, vehicle cushioning materials such as door interior cushioning materials, electronic parts, various industrial materials, and food containers. it can.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the following examples, methods for measuring the melting point, bulk density, heating dimensional change rate, chemical resistance, blackness, absorbance ratio, and burning rate are described below.

<Melting point>
Measured by the method described in JIS K7122: 1987 "Method for measuring the transition heat of plastic". That is, using a differential scanning calorimeter DSC220 type (manufactured by Seiko Denshi Kogyo Co., Ltd.), 7 mg of a sample was filled in a measurement container, and a nitrogen gas flow rate of 30 ml / min was used at a temperature between room temperature and 220 ° C. to 10 ° C./min. The temperature was raised, lowered, and raised repeatedly at the speed of raising and lowering the temperature, and the melting peak temperature of the DSC curve at the second temperature raising was defined as the melting point. When there were two or more melting peaks, the lower peak temperature was taken as the melting point.

<Bulk density>
The bulk density of the pre-expanded particles was measured as follows.
First, pre-expanded particles were filled up to 500 cm ^{3 and} a graduation of 500 cm ^{3 in} a measuring cylinder. When the graduated cylinder was visually observed from the horizontal direction and any pre-expanded particles reached the scale of 500 cm ³ , the filling of the pre-expanded particles into the graduated cylinder was completed at that point.
Next, the mass of the pre-expanded particles filled in the measuring cylinder was weighed with two significant figures after the decimal point, and the mass was defined as W (g).
And the bulk density of the pre-expanded particles was calculated by the following formula.
Bulk density (g / cm ³ ) = W / 500

<Bulk foam multiple>
The bulk expansion ratio of the pre-expanded particles was calculated by the following formula.
Bulk foam multiple (times) = 1 / density (g / cm ³ )

<Density>
The density of the foamed molded product was measured as follows.
It was measured by the method described in JIS K7122: 1999 “Foamed Plastics and Rubbers—Measurement of Apparent Density”.
A test piece of 50 cm ³ or more (100 cm ³ or more in the case of semi-rigid and soft materials) was cut so as not to change the original cell structure of the material, its mass was measured, and calculated by the following formula.
Density (g / cm ³ ) = Test piece mass (g) / Test piece volume (cm ³ )
Test specimen condition adjustment and measurement specimens were cut from a sample that had passed 72 hours or more after molding, and were subjected to atmospheric conditions of 23 ° C ± 2 ° C x 50% ± 5% or 27 ° C ± 2 ° C x 65% ± 5%. It has been left for more than an hour.

<Foaming multiple>
The expansion ratio of the foamed molded product was calculated by the following formula.
Foaming multiple (times) = 1 / density (g / cm ³ )

<Heating dimensional change rate>
The heating dimensional change rate was measured by the method B described in JIS K 6767: 1999K “foamed plastic-polyethylene test method”.
The test piece is 150 x 150 x original thickness (mm), and three straight lines are written in the center part in parallel with each other in the vertical and horizontal directions at intervals of 50 mm. After 22 hours, the sample was taken out and left in a standard state for 1 hour, and the vertical and horizontal line dimensions were measured by the following formula.
S = (L ₁ −L ₀ ) / L ₀ × 100
In the formula, S represents a heating dimensional change rate (%), L ₁ represents an average dimension (mm) after heating, and L ₀ represents an initial average dimension (mm).
The heating dimensional change rate S was evaluated according to the following criteria.
A: 0 ≦ S <1; the rate of dimensional change was low, and the dimensional stability was good.
Δ: 1 ≦ S <5; Although a change in size was observed, it was practically usable.
X: S ≧ 5; dimensional change was remarkably observed, and practical use was impossible.

<Chemical resistance>
A flat rectangular plate-shaped test piece having a length of 100 mm, a width of 100 mm, and a thickness of 20 mm was cut out from the foamed molded article and allowed to stand at 23 ° C. and a humidity of 50% for 24 hours. The test piece was cut out from the foam molded body so that the entire upper surface of the test piece was formed from the surface of the foam molded body.
Next, 1 g of gasoline as a chemical was uniformly applied and left for 60 minutes at 23 ° C. and 50% humidity.
Then, the chemical | medical agent was wiped off from the upper surface of the test piece, the upper surface of the test piece was observed visually, and it judged based on the following reference | standard.
○: Good No change
Δ: Slightly poor surface softening
×: Bad surface depression (shrinkage)

<Blackness>
For the evaluation of the hue, the L value of the surface layer of the molded product was measured using a color difference meter (trade name “ND-1001DP (manufactured by Nippon Denshoku Industries Co., Ltd. Integrating sphere method))).
The L value was measured with the measurement mode as Lab. The measurement area was 30 mmφ.
From the measurement result of the L value, the blackness was evaluated as follows.
A: L value is 0 or more and 20 or less.
(Triangle | delta): L value exceeds 20 and is 25 or less.
X: L value exceeds 25 and is 100 or less.
Further, the surface of the molded body was visually observed to determine color unevenness based on the following criteria.
○: The color of the molded body was uniform as a whole.
(Triangle | delta): The hue was non-uniform | heterogenous in a part of molded object.
X: The color of the molded body was not uniform as a whole.

<Absorbance ratio of the particle center or surface layer and polystyrene resin ratio>
The absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ) was measured as follows.
That is, an infrared absorption spectrum was obtained by performing ATR infrared spectroscopic analysis on the particle central part or surface of each of 10 randomly selected pre-expanded particles.
Here, in the measurement of the particle center, each pre-expanded particle is divided into two equal parts (for example, pre-expanded particles having a particle size of 5 mm are cut into 2.5 ± 0.5 mm), and the center of the cut surface ( The measurement was performed with the ATR prism in close contact with the inner side of the circle (at least 1/4 of the center of the circle).
In the measurement of the surface, the ATR prism is closely attached to the surface of each pre-expanded particle.
The absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ) was calculated from each infrared absorption spectrum, and the minimum absorbance ratio and the maximum absorbance ratio were excluded. The arithmetic average of the remaining 8 absorbance ratios was defined as the absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ). The absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ) was measured using, for example, a measurement apparatus sold under the trade name “Fourier Transform Infrared Spectrophotometer MAGMA 560” from Nicolet (current company name: Thermofisher). .
The polystyrene resin ratio (% by mass) was calculated from the absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ) based on the calibration curve described above.

<Absorbance ratio of whole particles and polystyrene resin ratio>
The absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ) was measured as follows.
That is, the pre-expanded particles were heated and reduced at a heating temperature of 200 ° C. to 250 ° C., cooled and pulverized, and 2 g of the pulverized product was precisely weighed.
This pulverized product was heated and kneaded under the following conditions with a small injection molding machine, and formed into a cylindrical shape having a diameter of 25 mm and a height of 2 mm to obtain a measurement sample.
As the small injection molding machine, for example, a machine sold by CSI under the trade name “CS-183” was used.
Injection molding conditions: heating temperature 200 ° C. to 250 ° C., kneading time 10 minutes The surface of the measurement sample was subjected to ATR infrared spectroscopy to obtain an infrared absorption spectrum.
The absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ) was calculated from each infrared absorption spectrum. The absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ) was measured using, for example, a measurement apparatus sold under the trade name “Fourier Transform Infrared Spectrophotometer MAGMA 560” from Nicolet (current company name: Thermofisher). .
The polystyrene resin ratio (% by mass) was calculated from the absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ) based on the calibration curve described above.

<Burning rate>
The burning rate was measured by a method in accordance with US automobile safety standard FMVSS 302.
The test piece had an expansion ratio of 30 times, 350 mm × 100 mm × 12 mm (thickness), and a skin was present on at least two sides of 350 mm × 100 mm.
In a foamed molded article having a foaming ratio of 30 times, if the combustion speed is 80 mm / min or less, it can be used favorably as a structural member in an automobile interior. Therefore, the combustion speed was evaluated according to the following criteria.
○: The combustion speed is 80 mm / min or less, which is good.
X: The combustion speed exceeds 80 mm / min, which is defective.

[Example 1]
1880 g of polypropylene resin (product name “F-744NP”, melting point: 140 ° C., manufactured by Prime Polymer Co., Ltd.) and 120 g of furnace black (product name “# 900”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. , Melt-kneaded and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene resin particles containing 6% by mass of furnace black in polypropylene resin.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Next, 800 g of the carbon-containing polypropylene resin particles are put into a 5 L autoclave with a stirrer, and 2 kg of pure water, 20 g of magnesium pyrophosphate, and 0.5 g of sodium dodecylbenzenesulfonate are added as an aqueous medium, and stirred in the aqueous medium. And then maintained for 10 minutes, and then heated to 60 ° C. to obtain an aqueous suspension.
Next, 400 g of a styrene monomer in which 0.8 g of dicumyl peroxide was dissolved in this suspension was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 135 ° C., which is 5 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and maintained for 2 hours to polymerize the styrene monomer in the carbon-containing polypropylene resin particles (first Polymerization).
Next, the reaction liquid of the first polymerization is set to 120 ° C., which is 20 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and 1.5 g of sodium dodecylbenzenesulfonate is added to this suspension, and then the polymerization is started. As an agent, 800 g of a styrene monomer in which 3.6 g of dicumyl peroxide was dissolved was dropped over 4 hours, and polymerization (second polymerization) was performed while absorbing the carbon-containing polypropylene resin particles.
After completion of the dropping, the mixture was held at 120 ° C. for 1 hour, then heated to 140 ° C. and held for 3 hours to complete the polymerization, thereby obtaining carbon-containing modified polystyrene resin particles.
Next, it was cooled to room temperature, and the resin particles were taken out from the 5 L autoclave. 2 kg of carbon-containing modified polystyrene resin particles and 2 L of water after taking out were again put into a 5 L autoclave with a stirrer, and 300 g of butane as a blowing agent was poured into a 5 L autoclave with a stirrer. After the injection, the temperature was raised to 70 ° C. and stirring was continued for 4 hours.
Then, it cooled to normal temperature, took out from the 5L autoclave, dehydrated and dried, and then obtained expandable carbon-containing modified polystyrene resin particles.
Next, the obtained expandable carbon-containing modified polystyrene resin particles were pre-expanded to a bulk expansion ratio of 30 times to obtain carbon-containing modified polystyrene resin expanded particles.
And the absorbance was measured using the obtained carbon-containing modified polystyrene resin foamed particles, and the polystyrene resin ratio was calculated.
Further, the obtained carbon-containing modified polystyrene resin expanded particles were allowed to stand at room temperature for 1 day, and then filled into a cavity of a mold having a size of 400 mm × 300 mm × 50 mm. 20 MPa of water vapor was introduced for 50 seconds and heated, and then cooled until the maximum surface pressure of the foamed molded product was reduced to 0.001 MPa to obtain a foamed molded product.
Under these molding conditions, a foamed molded article having good appearance and fusion was obtained.
And using the obtained carbon-containing modified polystyrene resin foam molded article, the expansion ratio, the heating dimensional change rate, the chemical resistance, and the blackness were measured.

[Example 2]
1880 g of polypropylene resin (product name “F-744NP”, melting point: 140 ° C., manufactured by Prime Polymer Co., Ltd.) and 120 g of furnace black (product name “# 900”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. , Melt-kneaded and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene resin particles containing 6% by mass of furnace black in polypropylene resin.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Next, 600 g of the carbon-containing polypropylene resin particles are put into a 5 L autoclave with a stirrer, and 2 kg of pure water, 20 g of magnesium pyrophosphate, and 0.5 g of sodium dodecylbenzenesulfonate are added as an aqueous medium, and the mixture is stirred and mixed in an aqueous medium. And then maintained for 10 minutes, and then heated to 60 ° C. to obtain an aqueous suspension.
Next, 300 g of a styrene monomer in which 0.6 g of dicumyl peroxide was dissolved in this suspension was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 135 ° C., which is 5 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and maintained for 2 hours to polymerize the styrene monomer in the carbon-containing polypropylene resin particles (first Polymerization).
Next, the reaction liquid of the first polymerization is set to 120 ° C., which is 20 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and 1.5 g of sodium dodecylbenzenesulfonate is added to this suspension, and then the polymerization is started. As an agent, 1100 g of a styrene monomer in which 4.2 g of dicumyl peroxide was dissolved was dropped over 5 hours and 30 minutes, and polymerization (second polymerization) was performed while absorbing the carbon-containing polypropylene resin particles.
After completion of the dropping, the mixture was held at 120 ° C. for 1 hour, then heated to 140 ° C. and held for 3 hours to complete the polymerization, thereby obtaining carbon-containing modified polystyrene resin particles.
Next, it was cooled to room temperature, and the resin particles were taken out from the 5 L autoclave. 2 kg of carbon-containing modified polystyrene resin particles and 2 L of water after taking out were again put into a 5 L autoclave with a stirrer, and 300 g of butane as a blowing agent was poured into a 5 L autoclave with a stirrer. After the injection, the temperature was raised to 70 ° C. and stirring was continued for 4 hours.
Then, it cooled to normal temperature, took out from the 5L autoclave, dehydrated and dried, and then obtained expandable carbon-containing modified polystyrene resin particles.
Next, the obtained expandable carbon-containing modified polystyrene resin particles were pre-expanded to a bulk expansion ratio of 30 times to obtain carbon-containing modified polystyrene resin expanded particles.
And the absorbance was measured using the obtained carbon-containing modified polystyrene resin foamed particles, and the polystyrene resin ratio was calculated.
Next, in the same manner as in Example 1, a carbon-containing modified polystyrene resin foam molded article was obtained.
And using the obtained carbon-containing modified polystyrene resin foam molded article, the expansion ratio, the heating dimensional change rate, the chemical resistance, and the blackness were measured.

[Example 3]
1880 g of polypropylene resin (product name “F-744NP”, melting point: 140 ° C., manufactured by Prime Polymer Co., Ltd.) and 120 g of furnace black (product name “# 900”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. , Melt-kneaded and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene resin particles containing 6% by mass of furnace black in polypropylene resin.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Next, 1000 g of the carbon-containing polypropylene resin particles are put into a 5 L autoclave with a stirrer, and 2 kg of pure water, 20 g of magnesium pyrophosphate, and 0.5 g of sodium dodecylbenzenesulfonate are added as an aqueous medium, and the mixture is stirred and mixed in an aqueous medium. And then maintained for 10 minutes, and then heated to 60 ° C. to obtain an aqueous suspension.
Next, 500 g of a styrene monomer in which 1.0 g of dicumyl peroxide was dissolved in this suspension was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 135 ° C., which is 5 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and maintained for 2 hours to polymerize the styrene monomer in the carbon-containing polypropylene resin particles (first Polymerization).
Next, the reaction liquid of the first polymerization is set to 120 ° C., which is 20 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and 1.5 g of sodium dodecylbenzenesulfonate is added to this suspension, and then the polymerization is started. 500 g of a styrene monomer in which 3 g of dicumyl peroxide was dissolved as an agent was dropped over 2 hours and 30 minutes, and polymerization (second polymerization) was carried out while absorbing the carbon-containing polypropylene resin particles.
After completion of the dropping, the mixture was held at 120 ° C. for 1 hour, then heated to 140 ° C. and held for 3 hours to complete the polymerization, thereby obtaining carbon-containing modified polystyrene resin particles.
Next, it was cooled to room temperature, and the resin particles were taken out from the 5 L autoclave. 2 kg of carbon-containing modified polystyrene resin particles and 2 L of water after taking out were again put into a 5 L autoclave with a stirrer, and 300 g of butane as a blowing agent was poured into a 5 L autoclave with a stirrer. After the injection, the temperature was raised to 70 ° C. and stirring was continued for 4 hours.
Then, it cooled to normal temperature, took out from the 5L autoclave, dehydrated and dried, and then obtained expandable carbon-containing modified polystyrene resin particles.
Next, the obtained expandable carbon-containing modified polystyrene resin particles were pre-expanded to a bulk expansion ratio of 30 times to obtain carbon-containing modified polystyrene resin expanded particles.
And the absorbance was measured using the obtained carbon-containing modified polystyrene resin foamed particles, and the polystyrene resin ratio was calculated.
Next, in the same manner as in Example 1, a carbon-containing modified polystyrene resin foam molded article was obtained.
And using the obtained carbon-containing modified polystyrene resin foam molded article, the expansion ratio, the heating dimensional change rate, the chemical resistance, and the blackness were measured.

[Example 4]
1940 g of polypropylene resin (manufactured by Prime Polymer, trade name “F-744NP”, melting point: 140 ° C.) and 60 g of furnace black (trade name “# 900”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. , Melt-kneaded and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene resin particles containing 3% by mass of furnace black in polypropylene resin.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Hereinafter, in the same manner as in Example 1, after obtaining carbon-containing modified polystyrene resin foamed particles, the carbon-containing modified polystyrene resin foamed particles were used to measure absorbance, and the polystyrene resin ratio was calculated. did.
Next, in the same manner as in Example 1, a carbon-containing modified polystyrene resin foam molded article was obtained.
And using the obtained carbon-containing modified polystyrene resin foam molded article, the expansion ratio, the heating dimensional change rate, the chemical resistance, and the blackness were measured.

[Example 5]
1840 g of polypropylene-based resin (manufactured by Prime Polymer, trade name “F-744NP”, melting point: 140 ° C.) and 160 g of furnace black (trade name “# 900”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. , Melt-kneaded and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene-based resin particles containing 8% by mass of furnace black in a polypropylene-based resin.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Hereinafter, in the same manner as in Example 1, after obtaining carbon-containing modified polystyrene resin foamed particles, the carbon-containing modified polystyrene resin foamed particles were used to measure absorbance, and the polystyrene resin ratio was calculated. did.
Next, in the same manner as in Example 1, a carbon-containing modified polystyrene resin foam molded article was obtained.
And using the obtained carbon-containing modified polystyrene resin foam molded article, the expansion ratio, the heating dimensional change rate, the chemical resistance, and the blackness were measured.

[Example 6]
1880 g of a polypropylene resin (manufactured by Prime Polymer, trade name “F-744NP”, melting point: 140 ° C.) and 120 g of furnace black (trade name “MA230”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is put into an extruder. By supplying, melt-kneading, and granulating pellets by strand cutting, spherical (egg-like) carbon-containing polypropylene resin particles containing 6% by mass of furnace black in polypropylene resin were obtained.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Hereinafter, in the same manner as in Example 1, after obtaining carbon-containing modified polystyrene resin foamed particles, the carbon-containing modified polystyrene resin foamed particles were used to measure absorbance, and the polystyrene resin ratio was calculated. did.
Next, in the same manner as in Example 1, a carbon-containing modified polystyrene resin foam molded article was obtained.
And using the obtained carbon-containing modified polystyrene resin foam molded article, the expansion ratio, the heating dimensional change rate, the chemical resistance, and the blackness were measured.

[Example 7]
1880 g of polypropylene resin (trade name “PC540R”, melting point: 132 ° C., manufactured by Sun Allomer Co., Ltd.) and 120 g of furnace black (trade name “# 900”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is supplied to an extruder. Then, the mixture was melt-kneaded and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene-based resin particles containing 6% by mass of furnace black in a polypropylene-based resin.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Next, 800 g of the carbon-containing polypropylene resin particles are put into a 5 L autoclave with a stirrer, and 2 kg of pure water, 20 g of magnesium pyrophosphate, and 0.5 g of sodium dodecylbenzenesulfonate are added as an aqueous medium, and stirred in the aqueous medium. And then maintained for 10 minutes, and then heated to 60 ° C. to obtain an aqueous suspension.
Next, 400 g of a styrene monomer in which 0.8 g of dicumyl peroxide was dissolved in this suspension was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 140 ° C., which is 8 ° C. higher than the melting point of the carbon-containing polypropylene resin particles, and maintained for 2 hours to polymerize the styrene monomer in the carbon-containing polypropylene resin particles (first Polymerization).
Next, the reaction liquid of the first polymerization is set to 125 ° C., which is 7 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and 1.5 g of sodium dodecylbenzenesulfonate is added to this suspension, and then the polymerization is started. As an agent, 800 g of a styrene monomer in which 3.6 g of dicumyl peroxide was dissolved was dropped over 4 hours, and polymerization (second polymerization) was performed while absorbing the carbon-containing polypropylene resin particles.
After completion of the dropping, the temperature was maintained at 125 ° C. for 1 hour, then heated to 140 ° C. and maintained for 3 hours to complete the polymerization, and in the same manner as in Example 1 except that the carbon-containing modified polystyrene resin particles were obtained. Expandable carbon-containing modified polystyrene resin particles were obtained.
Next, in the same manner as in Example 1, after obtaining carbon-containing modified polystyrene resin expanded particles, the carbon-containing modified polystyrene resin expanded particles were measured for absorbance, and the polystyrene resin ratio was determined. Calculated.
Next, in the same manner as in Example 1, a carbon-containing modified polystyrene resin foam molded article was obtained.
And using the obtained carbon-containing modified polystyrene resin foam molded article, the expansion ratio, the heating dimensional change rate, the chemical resistance, and the blackness were measured.

[Example 8]
1880 g of polypropylene resin (manufactured by Sun Allomer, trade name “PC540R”, melting point: 132 ° C., melting point: 140 ° C.) and 120 g of furnace black (trade name “MA230”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. It was supplied to a machine, melted and kneaded, and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene-based resin particles containing 6% by mass of furnace black in a polypropylene-based resin. The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Next, 800 g of the carbon-containing polypropylene resin particles are put into a 5 L autoclave with a stirrer, and 2 kg of pure water, 20 g of magnesium pyrophosphate, and 0.5 g of sodium dodecylbenzenesulfonate are added as an aqueous medium, and stirred in the aqueous medium. And then maintained for 10 minutes, and then heated to 60 ° C. to obtain an aqueous suspension.
Next, 400 g of a styrene monomer in which 0.8 g of dicumyl peroxide was dissolved in this suspension was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 135 ° C., which is 3 ° C. higher than the melting point of the carbon-containing polypropylene resin particles, and maintained for 2 hours to polymerize the styrene monomer in the carbon-containing polypropylene resin particles (first Polymerization).
Next, the reaction liquid of the first polymerization is set to 120 ° C. which is 12 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and 1.5 g of sodium dodecylbenzenesulfonate is added to this suspension, and then the polymerization is started. As an agent, 800 g of a styrene monomer in which 3.6 g of dicumyl peroxide was dissolved was dropped over 4 hours, and polymerization (second polymerization) was performed while absorbing the carbon-containing polypropylene resin particles.
After completion of the dropping, the mixture was held at 120 ° C. for 1 hour, then heated to 140 ° C. and held for 3 hours to complete the polymerization, thereby obtaining carbon-containing modified polystyrene resin particles.
Thereafter, the temperature of the reaction system was set to 60 ° C., and 40 g of tri (2,3-dibromopropyl) isocyanate (manufactured by Nippon Kasei Co., Ltd.) was added to this suspension. The mixture was heated to 4 hours and stirred for 4 hours to obtain carbon-containing modified polystyrene resin particles.
Next, it was cooled to room temperature, and the resin particles were taken out from the 5 L autoclave. 2 kg of carbon-containing modified polystyrene resin particles and 2 L of water after taking out were again put into a 5 L autoclave with a stirrer, and 300 g of butane as a blowing agent was poured into a 5 L autoclave with a stirrer. After the injection, the temperature was raised to 70 ° C. and stirring was continued for 4 hours.
Then, it cooled to normal temperature, took out from the 5L autoclave, dehydrated and dried, and then obtained expandable carbon-containing modified polystyrene resin particles.
Next, the obtained expandable carbon-containing modified polystyrene resin particles were pre-expanded to a bulk expansion ratio of 30 times to obtain carbon-containing modified polystyrene resin expanded particles.
And the absorbance was measured using the obtained carbon-containing modified polystyrene resin foamed particles, and the polystyrene resin ratio was calculated.
Further, the obtained carbon-containing modified polystyrene resin expanded particles were allowed to stand at room temperature for 1 day, and then filled into a cavity of a mold having a size of 400 mm × 300 mm × 50 mm. 20 MPa of water vapor was introduced for 50 seconds and heated, and then cooled until the maximum surface pressure of the foamed molded product was reduced to 0.001 MPa to obtain a foamed molded product.
Under these molding conditions, a foamed molded article having good appearance and fusion was obtained.
The obtained carbon-containing modified polystyrene resin foamed molded article was used to measure the expansion ratio, rate of change in heating dimensions, chemical resistance, blackness, and burning rate.

[Example 9]
1880 g of polypropylene resin (manufactured by Sun Allomer, trade name “PC540R”, melting point: 132 ° C., melting point: 140 ° C.) and 120 g of furnace black (trade name “MA230”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. It was supplied to a machine, melted and kneaded, and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene-based resin particles containing 6% by mass of furnace black in a polypropylene-based resin. The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Next, 800 g of the carbon-containing polypropylene resin particles are put into a 5 L autoclave with a stirrer, and 2 kg of pure water, 20 g of magnesium pyrophosphate, and 0.5 g of sodium dodecylbenzenesulfonate are added as an aqueous medium, and stirred in the aqueous medium. And then maintained for 10 minutes, and then heated to 60 ° C. to obtain an aqueous suspension.
Next, 400 g of a styrene monomer in which 0.8 g of dicumyl peroxide was dissolved in this suspension was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 135 ° C., which is 3 ° C. higher than the melting point of the carbon-containing polypropylene resin particles, and maintained for 2 hours to polymerize the styrene monomer in the carbon-containing polypropylene resin particles (first Polymerization).
Next, the reaction liquid of the first polymerization is set to 120 ° C. which is 12 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and 1.5 g of sodium dodecylbenzenesulfonate is added to this suspension, and then the polymerization is started. As an agent, 800 g of a styrene monomer in which 3.6 g of dicumyl peroxide was dissolved was dropped over 4 hours, and polymerization (second polymerization) was performed while absorbing the carbon-containing polypropylene resin particles.
After completion of the dropping, the mixture was held at 120 ° C. for 1 hour, then heated to 140 ° C. and held for 3 hours to complete the polymerization, thereby obtaining carbon-containing modified polystyrene resin particles.
Thereafter, the temperature of the reaction system was set to 60 ° C., and 100 g of tri (2,3-dibromopropyl) isocyanate (manufactured by Nippon Kasei Co., Ltd.) was added to this suspension. The mixture was heated to 4 hours and stirred for 4 hours to obtain carbon-containing modified polystyrene resin particles.
Next, it was cooled to room temperature, and the resin particles were taken out from the 5 L autoclave. 2 kg of carbon-containing modified polystyrene resin particles and 2 L of water after taking out were again put into a 5 L autoclave with a stirrer, and 300 g of butane as a blowing agent was poured into a 5 L autoclave with a stirrer. After the injection, the temperature was raised to 70 ° C. and stirring was continued for 4 hours.
Then, it cooled to normal temperature, took out from the 5L autoclave, dehydrated and dried, and then obtained expandable carbon-containing modified polystyrene resin particles.
Next, the obtained expandable carbon-containing modified polystyrene resin particles were pre-expanded to a bulk expansion ratio of 30 times to obtain carbon-containing modified polystyrene resin expanded particles.
And the absorbance was measured using the obtained carbon-containing modified polystyrene resin foamed particles, and the polystyrene resin ratio was calculated.
Further, the obtained carbon-containing modified polystyrene resin expanded particles were allowed to stand at room temperature for 1 day, and then filled into a cavity of a mold having a size of 400 mm × 300 mm × 50 mm. 20 MPa of water vapor was introduced for 50 seconds and heated, and then cooled until the maximum surface pressure of the foamed molded product was reduced to 0.001 MPa to obtain a foamed molded product.
Under these molding conditions, a foamed molded article having good appearance and fusion was obtained.
The obtained carbon-containing modified polystyrene resin foamed molded article was used to measure the expansion ratio, rate of change in heating dimensions, chemical resistance, blackness, and burning rate.

[Comparative Example 1]
1880 g of polypropylene resin (manufactured by Prime Polymer, trade name “F-744NP”, melting point: 140 ° C.) and 120 g of furnace black (trade name “CF9”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is put into an extruder. By supplying, melt-kneading, and granulating pellets by strand cutting, spherical (egg-like) carbon-containing polypropylene resin particles containing 6% by mass of furnace black in polypropylene resin were obtained.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Hereinafter, in the same manner as in Example 1, after obtaining carbon-containing modified polystyrene resin foamed particles, the carbon-containing modified polystyrene resin foamed particles were used to measure absorbance, and the polystyrene resin ratio was calculated. did.
Next, in the same manner as in Example 1, a carbon-containing modified polystyrene resin foam molded article was obtained.
And using the obtained carbon-containing modified polystyrene resin foam molded article, the expansion ratio, the heating dimensional change rate, the chemical resistance, and the blackness were measured.

[Comparative Example 2]
1880 g of polypropylene-based resin (manufactured by Prime Polymer, trade name “F-744NP”, melting point: 140 ° C.) and 120 g of furnace black (trade name “# 2600”, manufactured by Mitsubishi Chemical Corporation) are mixed and this mixture is extruded , Melt-kneaded and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene resin particles containing 6% by mass of furnace black in polypropylene resin.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Hereinafter, in the same manner as in Example 1, attempts were made to obtain carbon-containing modified polystyrene resin expanded particles (bulk expansion ratio 30 times). However, foaming properties were low, and only those having a bulk expansion ratio up to 15 times were obtained. There wasn't. Using these carbon-containing modified polystyrene resin expanded particles, the absorbance was measured, and the polystyrene resin ratio was calculated.
In addition, the foaming molding of the expansion ratio 30 times was not obtained.

[Comparative Example 3]
1880 g of polypropylene resin (product name “F-744NP”, melting point: 140 ° C., manufactured by Prime Polymer Co., Ltd.) and 120 g of furnace black (product name “# 900”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. , Melt-kneaded and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene resin particles containing 6% by mass of furnace black in polypropylene resin.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Next, 800 g of the carbon-containing polypropylene resin particles are put into a 5 L autoclave with a stirrer, and 2 kg of pure water, 20 g of magnesium pyrophosphate, and 0.5 g of sodium dodecylbenzenesulfonate are added as an aqueous medium, and stirred in the aqueous medium. And then maintained for 10 minutes, and then heated to 60 ° C. to obtain an aqueous suspension.
Next, 400 g of a styrene monomer in which 0.8 g of dicumyl peroxide was dissolved in this suspension was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 120 ° C., which is 20 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and maintained for 2 hours, and the styrene monomer is polymerized in the carbon-containing polypropylene resin particles (first Polymerization).
Next, the reaction liquid of the first polymerization is set to 110 ° C., which is 30 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and 1.5 g of sodium dodecylbenzenesulfonate is added to this suspension, and then the polymerization is started. As an agent, 800 g of a styrene monomer in which 3.6 g of dicumyl peroxide was dissolved was dropped over 4 hours, and polymerization (second polymerization) was performed while absorbing the carbon-containing polypropylene resin particles.
After completion of the dropping, the temperature was maintained at 110 ° C. for 1 hour, and then the temperature was increased to 140 ° C. and maintained for 3 hours to complete the polymerization in the same manner as in Example 1 except that the carbon-containing modified polystyrene resin particles were obtained. Expandable carbon-containing modified polystyrene resin particles were obtained.
Next, in the same manner as in Example 1, an attempt was made to obtain carbon-containing modified polystyrene resin expanded particles (bulk expansion ratio 30 times). I couldn't. Using these carbon-containing modified polystyrene resin expanded particles, the absorbance was measured, and the polystyrene resin ratio was calculated.
In addition, the foaming molding of the expansion ratio 30 times was not obtained.

[Comparative Example 4]
1880 g of polypropylene resin (product name “F-744NP”, melting point: 140 ° C., manufactured by Prime Polymer Co., Ltd.) and 120 g of furnace black (product name “# 900”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. , Melt-kneaded and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene resin particles containing 6% by mass of furnace black in polypropylene resin.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Next, 800 g of the carbon-containing polypropylene resin particles are put into a 5 L autoclave with a stirrer, and 2 kg of pure water, 20 g of magnesium pyrophosphate, and 0.5 g of sodium dodecylbenzenesulfonate are added as an aqueous medium, and stirred in the aqueous medium. And then maintained for 10 minutes, and then heated to 60 ° C. to obtain an aqueous suspension.
Next, 400 g of a styrene monomer in which 0.8 g of dicumyl peroxide was dissolved in this suspension was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 135 ° C., which is 5 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and maintained for 2 hours to polymerize the styrene monomer in the carbon-containing polypropylene resin particles (first Polymerization).
Next, the reaction liquid of the first polymerization is set to 110 ° C., which is 30 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and 1.5 g of sodium dodecylbenzenesulfonate is added to this suspension, and then the polymerization is started. As an agent, 800 g of a styrene monomer in which 3.6 g of dicumyl peroxide was dissolved was dropped over 4 hours, and polymerization (second polymerization) was performed while absorbing the carbon-containing polypropylene resin particles.
After completion of the dropping, the temperature was maintained at 110 ° C. for 1 hour, and then the temperature was increased to 140 ° C. and maintained for 3 hours to complete the polymerization in the same manner as in Example 1 except that the carbon-containing modified polystyrene resin particles were obtained. Expandable carbon-containing modified polystyrene resin particles were obtained.
Next, in the same manner as in Example 1, after obtaining carbon-containing modified polystyrene resin expanded particles, the carbon-containing modified polystyrene resin expanded particles were measured for absorbance, and the polystyrene resin ratio was determined. Calculated.
Next, in the same manner as in Example 1, a carbon-containing modified polystyrene resin foam molded article was obtained.
And using the obtained carbon-containing modified polystyrene resin foam molded article, the expansion ratio, the heating dimensional change rate, the chemical resistance, and the blackness were measured.

[Comparative Example 5]
1880 g of polypropylene resin (trade name “PC540R”, melting point: 132 ° C., manufactured by Sun Allomer Co., Ltd.) and 120 g of furnace black (trade name “# 900”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is supplied to an extruder. Then, the mixture was melt-kneaded and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene-based resin particles containing 6% by mass of furnace black in a polypropylene-based resin.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Next, 800 g of the carbon-containing polypropylene resin particles are put into a 5 L autoclave with a stirrer, and 2 kg of pure water, 20 g of magnesium pyrophosphate, and 0.5 g of sodium dodecylbenzenesulfonate are added as an aqueous medium, and stirred in the aqueous medium. And then maintained for 10 minutes, and then heated to 60 ° C. to obtain an aqueous suspension.
Next, 400 g of a styrene monomer in which 0.8 g of dicumyl peroxide was dissolved in this suspension was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 145 ° C., which is 13 ° C. higher than the melting point of the carbon-containing polypropylene resin particles, and held for 2 hours, and the styrene monomer is polymerized in the carbon-containing polypropylene resin particles (first Polymerization).
Next, the reaction liquid of the first polymerization was set to 145 ° C. which is 13 ° C. higher than the melting point of the carbon-containing polypropylene resin particles, and 1.5 g of sodium dodecylbenzenesulfonate was added to this suspension, and then polymerization was started. As an agent, 800 g of a styrene monomer in which 3.6 g of dicumyl peroxide was dissolved was dropped over 4 hours, and polymerization (second polymerization) was performed while absorbing the carbon-containing polypropylene resin particles.
After the completion of this dropping, after holding at 145 ° C. for 1 hour, the temperature was raised to 145 ° C. and held for 3 hours to complete the polymerization, in the same manner as in Example 1 except that carbon-containing modified polystyrene resin particles were obtained. Expandable carbon-containing modified polystyrene resin particles were obtained.
Next, in the same manner as in Example 1, an attempt was made to obtain carbon-containing modified polystyrene resin expanded particles (bulk expansion ratio 30 times). I couldn't. Using these carbon-containing modified polystyrene resin expanded particles, the absorbance was measured, and the polystyrene resin ratio was calculated.
In addition, the foaming molding of the expansion ratio 30 times was not obtained.

[Comparative Example 6]
1880 g of polypropylene resin (product name “F-744NP”, melting point: 140 ° C., manufactured by Prime Polymer Co., Ltd.) and 120 g of furnace black (product name “# 900”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. , Melt-kneaded and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene resin particles containing 6% by mass of furnace black in polypropylene resin.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Next, 1200 g of the carbon-containing polypropylene resin particles are put into a 5 L autoclave with a stirrer, and 2 kg of pure water, 20 g of magnesium pyrophosphate, and 0.5 g of sodium dodecylbenzenesulfonate are added as an aqueous medium, and the mixture is stirred and mixed in an aqueous medium. And then kept for 10 minutes, and then heated to 60 ° C. to obtain an aqueous suspension.
Next, 400 g of a styrene monomer in which 0.8 g of dicumyl peroxide was dissolved in this suspension was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 135 ° C., which is 5 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and maintained for 2 hours to polymerize the styrene monomer in the carbon-containing polypropylene resin particles (first Polymerization).
Next, the reaction liquid of the first polymerization is set to 120 ° C., which is 20 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and 1.5 g of sodium dodecylbenzenesulfonate is added to this suspension, and then the polymerization is started. As an agent, 400 g of a styrene monomer in which 2.4 g of dicumyl peroxide was dissolved was dropped over 2 hours, and polymerization (second polymerization) was performed while absorbing the carbon-containing polypropylene resin particles.
After completion of the dropping, the temperature was raised to 120 ° C. for 1 hour, and then heated to 140 ° C. and held for 3 hours to complete the polymerization, except that carbon-containing modified polystyrene resin particles were obtained. Expandable carbon-containing modified polystyrene resin particles were obtained.
Next, in the same manner as in Example 1, an attempt was made to obtain carbon-containing modified polystyrene resin expanded particles (bulk expansion ratio 30 times). However, foaming properties were low, and only those having a bulk expansion ratio up to 10 times were obtained. I couldn't.
In addition, the foaming molding of the expansion ratio 30 times was not obtained.

[Comparative Example 7]
1880 g of polypropylene resin (product name “F-744NP”, melting point: 140 ° C., manufactured by Prime Polymer Co., Ltd.) and 120 g of furnace black (product name “# 900”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. , Melt-kneaded and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene resin particles containing 6% by mass of furnace black in polypropylene resin.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Next, 200 g of the carbon-containing polypropylene resin particles are put into a 5 L autoclave equipped with a stirrer, and 2 kg of pure water, 20 g of magnesium pyrophosphate, and 0.5 g of sodium dodecylbenzenesulfonate are added as an aqueous medium, and stirred in the aqueous medium. And then maintained for 10 minutes, and then heated to 60 ° C. to obtain an aqueous suspension.
Next, 100 g of a styrene monomer in which 0.8 g of dicumyl peroxide was dissolved in this suspension was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 135 ° C., which is 5 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and maintained for 2 hours to polymerize the styrene monomer in the carbon-containing polypropylene resin particles (first Polymerization).
Next, the reaction liquid of the first polymerization is set to 120 ° C., which is 20 ° C. lower than the melting point of the carbon-containing polypropylene resin particles, and 1.5 g of sodium dodecylbenzenesulfonate is added to this suspension, and then the polymerization is started. As an agent, 1700 g of a styrene monomer in which 5.4 g of dicumyl peroxide was dissolved was dropped over 8 hours and 30 minutes, and polymerization (second polymerization) was performed while absorbing the carbon-containing polypropylene resin particles.
After completion of the dropping, the temperature was raised to 120 ° C. for 1 hour, and then heated to 140 ° C. and held for 3 hours to complete the polymerization, except that carbon-containing modified polystyrene resin particles were obtained. Expandable carbon-containing modified polystyrene resin particles were obtained.
Next, in the same manner as in Example 1, carbon-containing modified polystyrene resin expanded particles were obtained.
Next, in the same manner as in Example 1, a carbon-containing modified polystyrene resin foam molded article was obtained.
Then, using the obtained carbon-containing modified polystyrene resin foamed molded article, the expansion ratio, the heating dimensional change rate, and the chemical resistance were measured.

Table 1 shows the production conditions of Examples 1 to 9, and the measurement results and evaluation results of the above tests on the obtained carbon-containing modified polystyrene resin expanded particles and the expanded molded article.
Table 2 shows the production conditions of Comparative Examples 1 to 7, and the measurement results and evaluation results of the above tests for the obtained carbon-containing modified polystyrene resin expanded particles and the expanded molded article.
In Tables 1 and 2, “PP” indicates a polypropylene resin, and “PS” indicates a polystyrene resin.
In Tables 1 and 2, PP resin A represents F-744NP manufactured by Prime Polymer, and PP resin B represents PC540R manufactured by Sun Allomer.

From the results shown in Tables 1 and 2, the foam molded articles produced in Examples 1 to 9 according to the present invention were 698 cm ⁻¹ and 1376 cm obtained from the infrared absorption spectrum of the particle center measured by ATR infrared spectroscopy. Manufactured in Comparative Examples 1 to 7 in which the ratio of the polystyrene resin at the center of the particle calculated from the absorbance ratio at ^-1 (D ₆₉₈ / D ₁₃₇₆ ) is less than 1.2 times the polystyrene resin ratio of the entire particle Compared with the foamed molded article, the heating dimensional change rate, chemical resistance and blackness were excellent.
Further, foamed molded body manufactured in Examples 1 to 9, the absorbance ratio at 698cm ^-1 and 1376cm ^-1 obtained from an infrared absorption spectrum of the measured particle surface by ATR method infrared spectroscopy _{(D 698 /} D ₁₃₇₆ ) Was 2.09, the foam moldability was superior to the foam molded article produced in Comparative Example 2.
In addition, the foam molded articles produced in Examples 1 to 9 have excellent foam moldability as compared with the foam molded article produced in Comparative Example 3 in which the second polymerization temperature is 30 ° C. lower than the melting point of the carbon-containing polypropylene resin particles. It was.
Further, the foam molded articles produced in Examples 1 to 9 have excellent foam moldability as compared with the foam molded article produced in Comparative Example 5 in which the second polymerization temperature is 13 ° C. higher than the melting point of the carbon-containing polypropylene resin particles. It was.
Moreover, compared with the foaming molding manufactured in Comparative Example 6 which contains about 67 mass parts of polystyrene resins with respect to 100 mass parts of carbon-containing polypropylene resins, the foaming moldings produced in Examples 1 to 9 include: The foam moldability was excellent.
Therefore, according to the present invention, it is possible to improve the disadvantages of both the polystyrene resin foam molded product and the polypropylene resin foam molded product, and to perform foam molding excellent in rigidity, foam moldability, chemical resistance, heat resistance and blackness. It has been demonstrated that the body can be provided.

Using a molded body made of polystyrene resin and polypropylene resin as a standard sample, the absorbance ratio of this standard sample is measured, and the relationship between the polystyrene resin ratio (mass%) and the absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ) is graphed. This is a calibration curve.

Claims (16)

Containing carbon-containing polypropylene resin,
Obtained from an infrared absorption spectrum of a particle center part containing 100 parts by mass or more and less than 400 parts by mass of a polystyrene resin with respect to 100 parts by mass of the carbon-containing polypropylene resin and measured by ATR infrared spectroscopy. Carbon content in which the polystyrene resin ratio at the center of the particle calculated from the absorbance ratio (D ₆₉₈ / D ₁₃₇₆ ) at ₆₉₈ cm ⁻¹ and 1376 cm ⁻¹ is 1.2 times or more of the polystyrene resin ratio of the entire particle Modified polystyrene resin particles.   The carbon-containing modified polystyrene resin particles according to claim 1, wherein the flame-retardant is contained in an amount of 1.5 parts by mass or more and less than 6 parts by mass with respect to 100 parts by mass of the carbon-containing polypropylene resin. Claim absorbance ratio at 698cm ^-1 and 1376cm ^-1 obtained from an infrared absorption spectrum of the measured particle surface by ATR method infrared spectroscopy _{(D 698 /} D ₁₃₇₆₎ is in a range of 0.1 to 2.5 3. The carbon-containing modified polystyrene resin particles according to 1 or 2.   The average particle diameter of carbon in the carbon-containing polypropylene resin is 15 nm to 35 nm before being contained in the polypropylene resin, and includes 1 to 8% by mass of carbon particles. Carbon-containing modified polystyrene resin particles as described in the item.   The carbon-containing modified polystyrene resin particles according to claim 2, wherein the flame retardant is tri (2,3-dibromopropyl) isocyanate.   Expandable carbon-containing modified polystyrene resin particles obtained by impregnating the carbon-containing modified polystyrene resin particles according to any one of claims 1 to 5 with a foaming agent.   Carbon-containing modified polystyrene-based resin expanded particles obtained by pre-expanding the expandable carbon-containing modified polystyrene-based resin particles according to claim 6.   A carbon-containing modified polystyrene resin foam molded article obtained by filling the mold with the carbon-containing modified polystyrene resin foamed particles according to claim 7 and performing foam molding.   The carbon-containing modified polystyrene system according to claim 8, wherein the shrinkage ratio in dimensional change measurement under the condition of 80 ° C according to JIS K 6767 is 1.0% or less, and the expansion ratio is in the range of 20 to 40 times. Resin foam molding. A step of dispersing 100 parts by mass of carbon-containing polypropylene resin particles, 100 parts by mass or more and less than 400 parts by mass of a styrene monomer, and a polymerization initiator in an aqueous suspension containing a dispersant;
Heating the obtained dispersion to a temperature at which the styrenic monomer is not substantially polymerized to impregnate the carbon-containing polypropylene resin particles with the styrenic monomer;
A step of performing the first polymerization of the styrene monomer at a temperature of (T-10) ° C. to (T + 20) ° C. when the melting point of the carbon-containing polypropylene resin particles is T ° C .;
Subsequent to the first polymerization step, a styrene monomer and a polymerization initiator are added, and the temperature is set to (T-25) ° C. to (T + 10) ° C., thereby the carbon-containing polypropylene resin. A method for producing carbon-containing modified polystyrene resin particles, comprising impregnating the particles with the styrene monomer and performing a second polymerization.   The method for producing carbon-containing modified polystyrene resin particles according to claim 10, further comprising a step of impregnating the resin particles during the second polymerization or the resin particles after the completion of the second polymerization with a flame retardant.   The method for producing carbon-containing modified polystyrene resin particles according to claim 10 or 11, wherein the melting point of the carbon-containing polypropylene resin particles is 120 ° C to 145 ° C.   The method for producing carbon-containing modified polystyrene resin particles according to any one of claims 10 to 12, wherein the polypropylene resin in the carbon-containing polypropylene resin is a propylene-ethylene copolymer.   A foamable carbon-containing modified polystyrene obtained by impregnating a carbon-containing modified polystyrene-based resin particle obtained by the method for producing a carbon-containing modified polystyrene-based resin particle according to any one of claims 10 to 13 with a foaming agent. For producing expandable carbon-containing modified polystyrene resin particles to obtain resin particles.   The carbon-containing modified polystyrene type | system | group which heats the foamable carbon containing modified polystyrene type resin particle obtained by the manufacturing method of the expandable carbon containing modified polystyrene type resin particle of Claim 14, and pre-expands it, and obtains a foamed particle A method for producing resin foam particles.   The carbon-containing modified polystyrene resin foam particles obtained by the method for producing the carbon-containing modified polystyrene resin foam particles according to claim 15 are filled in a cavity of a molding die, then subjected to in-mold foam molding, and then molded. A method for producing a carbon-containing modified polystyrene-based resin foam molded article in which a body is released from a mold.

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