JP2013123851A - Method for reducing odor in composite resin particle, composite resin particle, foamable particle, prefoamed particle, foam molded product and automobile interior material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently reducing odor from a composite resin particle containing a polyolefin based resin and a polystyrene based resin.SOLUTION: The composite resin particle for manufacturing a foam molded product containing polyolefin-based resin and polystyrene-based resin is fluidized by a gas of (T-40)°C to (T-10)°C (T is softening temperature of composite resin particle) which is blown from the lower part of a container in the container, to reduce the odor of the composite resin particle to an odor level value of ≤200 in a 55°C measuring atmosphere, in a method for reducing the odor in the composite resin particles.

Description

  The present invention relates to a method for reducing odor in composite resin particles, composite resin particles, expandable particles, pre-expanded particles, foamed molded products, and automobile interior materials. More specifically, the present invention relates to a method for reducing odor in composite resin particles containing a polyolefin resin and a polystyrene resin, composite resin particles, expandable particles, pre-expanded particles, a foam molded article, and an automobile interior material.

Conventionally, it is known that a foam-molded product obtained by in-mold molding of polystyrene resin pre-expanded particles is excellent in rigidity, heat insulation, light weight, water resistance and foam moldability. However, this foam molded article has a problem that it is inferior in chemical resistance and impact resistance. In addition, there is a problem that a lot of odor is generated and it is difficult to use for automobile interior use.
On the other hand, it is known that a foam-molded body made of a polyolefin resin has little odor and is excellent in chemical resistance and impact resistance. Therefore, this foaming molding is used for automobile-related parts. However, since the polyolefin-based resin is inferior in foaming gas retention, it is necessary to precisely control the foam molding conditions, resulting in a problem that the manufacturing cost is high. In addition, there is also a problem that the rigidity is inferior to that of the styrene resin foam molded article.

  Therefore, in view of the above circumstances, chemical resin resistance and rigidity are improved from composite resin particles containing polystyrene resin and polyolefin resin, which have improved the disadvantages of both polystyrene resin foam molding and polyolefin resin foam molding. An excellent foamed molded product is obtained. However, even in such a foamed molded product, a lower level of odor content is required for automobile-related parts (particularly, automobile interior materials).

Since it is known that the odor originates from the raw material and manufacturing method of the composite resin particles, in order to reduce it, there is a method of reducing after processing the composite resin particles. For example, Japanese Patent Laid-Open No. 10-195129 (Patent Document 1) discloses a method for reducing volatile components such as unreacted monomers from polystyrene polymer particles.
This publication describes that drying is performed at a drying temperature of 200 ° C. or lower until the ratio of volatile components contained after the reduction is 20 wt% or lower.

JP-A-10-195129

In general, in order to efficiently reduce the odor contained in the resin particles, it is only necessary to raise the temperature and dry the resin particles. However, if the temperature is raised too much, the resin particles may coalesce.
Therefore, efficient use of odors from composite resin particles containing polyolefin resin and polystyrene resin to enable use in applications requiring lower levels of odor content (for example, automobile interior materials). A reduction method has been desired.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive research. As a result, composite resin particles containing a polyolefin resin and a polystyrene resin were blown from the bottom of the container in the container (T -40) C. to (T-10) C. (T is the softening temperature of the composite resin particles). The odor derived from the raw material and production method of the composite resin particles is surprisingly efficiently reduced. The present invention has been completed by finding out what can be done.

  Thus, according to the present invention, composite resin particles for producing a foamed molded article containing a polyolefin resin and a polystyrene resin were blown from the bottom of the container in a container (T-40) ° C. to (T- 10) The odor in the composite resin particles is reduced to an odor level value of 200 or less in a measurement atmosphere at 55 ° C. by flowing in a gas at C (T is a softening temperature of the composite resin particles). A method for reducing odor in the composite resin particles is provided.

Moreover, according to this invention, the composite resin particle with which the odor obtained by said method was reduced is provided.
Moreover, according to this invention, the expandable particle obtained by making said composite resin particle impregnate a foaming agent is provided.
Moreover, according to this invention, the pre-expanded particle obtained by carrying out the pre-expansion of said expandable particle is provided.
Further, according to the present invention, there is provided an expandable molded article obtained by molding the above pre-expanded particles in a mold and having an odor level value of 200 or less in a measurement atmosphere at 55 ° C.
Furthermore, according to this invention, the automotive interior material derived from said foaming molding is provided.

According to the present invention, it is possible to obtain composite resin particles, expandable resin particles, and pre-expanded particles containing polyolefin resin and polystyrene resin, in which coalescence of particles is suppressed and odor is low. As a result, it is possible to obtain a foamed molded article that can be used for automobile interior applications that require a lower level of odor content than conventional ones.
Furthermore, the gas blown from the lower part of the container is discharged out of the container, and again blown and circulated together with new gas from the lower part of the container, and the circulating gas contains 4% by volume or more of the new gas. It is possible to obtain composite resin particles in which coalescence between particles is suppressed and there is less odor.
Moreover, when the polyolefin resin is a polyethylene resin, the coalescence of particles is further suppressed by flowing with a gas at (T-30) ° C. to (T-10) ° C., and the composite resin has less odor. Particles can be obtained.
Furthermore, when the polyolefin-based resin is a polypropylene-based resin, the coalescence between particles is further suppressed by flowing with a gas at (T-40) ° C. to (T-15) ° C., and the composite resin has less odor. Particles can be obtained.

In addition, the composite resin particles can be obtained by being put in a container in which gas is blown from the lower part, so that the coalescence of the particles is further suppressed and the composite resin particles with less odor can be obtained.
Furthermore, since the composite resin particles contain 100 parts by weight of polyolefin resin and 100 to 500 parts by weight of polystyrene resin, the composite resin particles are excellent in impact resistance, chemical resistance, etc., and coalescence between particles is suppressed, and Composite resin particles with little odor can be obtained.
In addition, the composite resin particles are polyolefin-modified styrene resin particles obtained by polymerizing by impregnating polyolefin resin particles with styrene monomers, so that they are more excellent in impact resistance, chemical resistance, It is possible to obtain composite resin particles in which coalescence of particles is suppressed and the odor is small.
Furthermore, when the odor is derived from a polymerization initiator or a volatile organic compound when producing a polystyrene resin constituting the composite resin, it can be reduced by the method of the present invention.

It is a schematic explanatory drawing of the measuring method of an odor level value. 4 is a photograph of a cross section of modified styrene resin particles of Example 2. 2 is a cross-sectional photograph of modified styrene resin particles of Example 3. 4 is a cross-sectional photograph of modified styrene resin particles of Example 4. 6 is a photograph of a cross section of modified styrene resin particles of Example 5.

  The method for reducing odor in composite resin particles containing a polyolefin resin and a polystyrene resin according to the present invention is such that composite resin particles containing a polyolefin resin and a polystyrene resin are blown into the container from the bottom of the container. In addition, by flowing in a gas at (T-40) ° C. to (T-10) ° C. (T is the softening temperature of the composite resin particles), the odor derived from the raw material and production method of the composite resin particles is measured at 55 ° C. Below is a method to reduce the odor level value to 200 or less.

In the present invention, the odor is an odor that can be measured by a portable odor sensor XP-329IIIR manufactured by New Cosmos, and is derived from the raw material and manufacturing method of the composite resin particles. Specifically, the odor is derived from a volatile organic compound (VOC) (for example, a styrene monomer) or a polymerization initiator for producing a polystyrene resin constituting the composite resin (for example, a polymerization initiator). Decomposition product).
In the present invention, since the composite resin particles are caused to flow by blowing gas from the lower part of the container, the odor can be efficiently reduced. Here, the gas is air, an inert gas (for example, nitrogen) or the like, and usually air is used.

(Odor reduction conditions)
The container used in the present invention is a container capable of causing particles in the container to flow while blowing gas from the lower part of the container, and the shape of the container is not particularly limited as long as there is a gas blowing port in the lower part. The container usually has a discharge port in the upper part for discharging the blown gas. It is preferable to provide a countersunk plate for preventing the composite resin particles from entering the blowing port at the lower part of the container. A number of holes through which gas can normally pass are provided in the eye plate. This hole may have a shape that blows gas vertically or may have a shape that blows obliquely. From the viewpoint of increasing the odor reduction efficiency, it is preferable to use a countersunk plate having holes of both shapes. Furthermore, in order to raise the odor reduction effect, a stirring device may be provided in the container.
As such a container, for example, a fluidized bed drying apparatus generally used for drying granular materials can be used. Specifically, a swirl type fluidized bed drying device with a built-in bug (for example, Slit Flow (registered trademark) (FBS type) manufactured by Okawara Seisakusho Co., Ltd.) may be used.

In the method of the present invention, the composite resin particles may be put in a container before blowing gas from the lower part, or may be put in a container in which gas is blown from the lower part. Among these, it is preferable to put in the container into which gas is blown from the lower part from the viewpoint of improving the odor reduction efficiency.
The temperature of the gas used in the present invention is (T-40) ° C. to (T-10) ° C. when the softening temperature of the composite resin particles is T ° C. When it is lower than (T-40) ° C., the reduction of odor may be insufficient. When the temperature is higher than (T-10) ° C., the composite resin particles may be bonded together. A more preferable gas temperature is (T-35) ° C. to (T-10) ° C. In addition, the softening temperature here means the penetration temperature referred to in JIS K7196.

The flow rate of the gas is equal to or higher than the minimum flow rate required to cause the composite resin particles in the container to flow, and may vary depending on the particle size and amount of the composite resin particles in the container.
The flow rate of the gas can be changed according to the air volume of the blown gas, and the fluidity can be adjusted by adjusting the air volume. When the air volume is small, the composite resin particles may not flow sufficiently. Further, when the air volume is large, the composite resin particles may be scattered. There is an appropriate flow rate range for efficiently flowing the composite resin particles. A preferred range is 0.5 to 2.0 m / sec, more preferably 0.7 to 1.6 m / sec. The appropriate flow rate can be determined by the pressure loss experienced when the blown gas passes through the composite resin particles. The pressure loss is preferably in the range of 1 to 10 kPa, more preferably in the range of 2 to 6 kPa. If the pressure loss due to the gaseous resin is within this range, the composite resin particles can be reliably flowed.

The gas blowing time varies depending on the gas temperature and flow rate. When the gas temperature is constant, the time decreases as the flow rate increases, and conversely the time increases as the flow rate decreases. When the temperature is constant, the time becomes shorter as the temperature becomes higher, and conversely, the time becomes longer as the temperature becomes lower. In any case, the time for blowing the gas is until the odor level value is 200 or less in the measurement atmosphere at 55 ° C.
The gas blown from the lower part of the container may be circulated by being discharged out of the container and blown again with new gas from the lower part of the container. By circulating, the running cost required for odor reduction can be reduced. When circulating, it is preferable that the circulating gas contains 4% by volume or more of new gas.

(Composite resin particles)
The composite resin containing a polyolefin resin and a polystyrene resin means a resin in a state where the polyolefin resin and the polystyrene resin are mixed uniformly or non-uniformly.
It does not specifically limit as polyolefin-type resin, A well-known resin can be used. The polyolefin resin may be cross-linked. For example, polyethylene resins such as branched low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, and cross-linked products of these polymers And polypropylene resins such as propylene homopolymer, propylene-vinyl acetate copolymer, ethylene-propylene random copolymer, propylene-1-butene copolymer, and ethylene-propylene-butene random copolymer. In the above example, low density is preferably 0.91~0.94g / cm ^3, more preferably 0.91~0.93g / cm ^3. High density is preferably 0.95~0.97g / cm ^3, more preferably 0.95~0.96g / cm ^3. The medium density is an intermediate density between these low density and high density.

  The polystyrene resin is polystyrene or a copolymer of styrene as a main component and another monomer copolymerizable with styrene. The main component means that styrene accounts for 70% by weight or more of the total monomers. Examples of other monomers include α-methylstyrene, p-methylstyrene, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, alkyl acrylate ester, alkyl methacrylate ester, divinylbenzene, polyethylene glycol dimethacrylate, and the like. . In the examples, alkyl means alkyl having 1 to 8 carbon atoms.

  Examples of the polyethylene resin include branched low density polyethylene, linear low density polyethylene, and ethylene-vinyl acetate copolymer. Examples of the polypropylene resin include ethylene-propylene random copolymers, and polystyrene resins include: More preferred is polystyrene, a styrene-alkyl acrylate copolymer, or a styrene-methacrylic acid alkyl ester copolymer.

The polystyrene resin is contained in the composite resin in the range of 100 to 500 parts by weight with respect to 100 parts by weight of the polyolefin resin. Moreover, the compounding quantity of the styrene-type monomer of the polystyrene-type resin raw material with respect to 100 weight part of polyolefin-type resin particles is also 100-500 weight part same as a polystyrene-type resin.
When there is more content of a polystyrene-type resin than 500 weight part, the crack resistance of a foaming molding may fall. On the other hand, if the amount is less than 100 parts by weight, the crack resistance is greatly improved, but the dissipation of the foaming agent from the surface of the expandable resin particles tends to be accelerated. Therefore, the bead life of the expandable resin particles may be shortened due to a decrease in the retention of the foaming agent. A more preferable content of the polystyrene-based resin is 100 to 400 parts by weight, and a more preferable content is 150 to 400 parts by weight.

As the composite resin, a resin obtained by simply mixing both resins can be used, but a polyolefin-modified styrene resin (also referred to as a modified styrene resin in some cases) described below is preferable. A more preferable composite resin is a polyethylene-modified styrene resin or a polypropylene-modified styrene resin.
The composite resin particles may contain a colorant such as carbon black, iron oxide, and graphite.
The polyolefin-modified styrene resin particles (also referred to as modified resin particles) can be obtained by adding a styrene monomer to an aqueous medium in which the polyolefin resin particles are dispersed and held for polymerization. A method for producing composite resin particles will be described below.

The polyolefin resin particles can be obtained by a known method. For example, polyolefin resin particles can be produced by first melt-extruding an olefin resin using an extruder and then granulating it by underwater cutting, strand cutting, or the like. Usually, the shape of the polyolefin resin particles to be used is, for example, a true sphere, an oval sphere (egg), a cylinder, a prism, a pellet, or a granular. Hereinafter, the polyolefin resin particles are also referred to as micropellets.
Polyolefin resin particles include talc, calcium silicate, calcium stearate, synthetic or naturally produced silicon dioxide, ethylene bis-stearic acid amide, methacrylate ester copolymer and other cell regulators, triallyl isocyanurate hexabromide And a flame retardant such as carbon black, iron oxide, and a colorant such as graphite.

Next, the micropellets are dispersed in an aqueous medium in a polymerization vessel and polymerized while impregnating the styrenic monomer into the micropellets.
Examples of the aqueous medium include water and a mixed medium of water and a water-soluble solvent (for example, alcohol). A solvent (plasticizer) such as toluene, xylene, cyclohexane, ethyl acetate, dioctyl phthalate, or tetrachloroethylene may be added to the styrene monomer.
The impregnation of the polyolefin resin particles with the styrene monomer may be performed while polymerizing, or may be performed before the polymerization is started. Of these, it is preferable to carry out the polymerization. When the polymerization is performed after impregnation, polymerization of the styrene monomer near the surface of the polyolefin resin particles tends to occur, and the styrene monomer not impregnated in the polyolefin resin particles is polymerized alone. In some cases, a large amount of fine particle polystyrene resin particles are produced.

  An oil-soluble radical polymerization initiator can be used for the polymerization of the styrene monomer. As this polymerization initiator, a polymerization initiator generally used for the polymerization of styrene monomers can be used. For example, benzoyl peroxide, lauroyl peroxide, t-butyl peroxy octoate, t-hexyl peroxy octoate, t-butyl peroxy benzoate, t-amyl peroxy benzoate, t-butyl peroxybivalate, t- Butyl peroxyisopropyl carbonate, t-hexyl peroxyisopropyl carbonate, t-butyl peroxy-3,3,5-trimethylcyclohexanoate, di-t-butylperoxyhexahydroterephthalate, 2,2-di-t- Examples thereof include organic peroxides such as butyl peroxybutane, di-t-hexyl peroxide, and dicumyl peroxide, and azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile. These oil-soluble radical polymerization initiators may be used alone or in combination.

Various methods can be used as a method of adding the polymerization initiator to the aqueous medium in the polymerization vessel. For example,
(A) A method in which a polymerization initiator is dissolved and contained in a styrene monomer in a container different from the polymerization container, and the styrene monomer is supplied into the polymerization container.
(B) A solution is prepared by dissolving the polymerization initiator in a part of a styrene monomer, a solvent such as isoparaffin, or a plasticizer. A method of simultaneously supplying this solution and a predetermined amount of styrenic monomer into the polymerization vessel,
(C) A dispersion in which a polymerization initiator is dispersed in an aqueous medium is prepared. Examples thereof include a method of supplying the dispersion and the styrene monomer into a polymerization vessel.

In general, the polymerization initiator is preferably added in an amount of 0.02 to 2.0% by weight based on the total amount of the styrene monomer used.
It is preferable to dissolve a water-soluble radical polymerization inhibitor in the aqueous medium. The water-soluble radical polymerization inhibitor not only suppresses the polymerization of the styrene monomer on the surface of the polyolefin resin particles, but also prevents the styrene monomer floating in the aqueous medium from being polymerized alone. This is because the generation of fine particles can be reduced.

As the water-soluble radical polymerization inhibitor, a polymerization inhibitor that can dissolve 1 g or more in 100 g of water can be used. For example, thiocyanate such as ammonium thiocyanate, zinc thiocyanate, sodium thiocyanate, potassium thiocyanate, and aluminum thiocyanate. Nitrate, mercapto Ethanol, monothiopropylene glycol, thioglycerol, thioglycolic acid, thiohydroacrylic acid, thiolactic acid, thiomalic acid, thioethanolamine, 1,2-dithioglycerol, 1,3-dithioglycerol, etc. Water-soluble sulfur-containing organic compounds, may be mentioned addition of ascorbic acid, ascorbic acid sodium or the like. Of these, nitrite is particularly preferable.
As the usage-amount of the said water-soluble radical polymerization inhibitor, 0.001-0.04 weight part is preferable with respect to 100 weight part of water of an aqueous medium.

In addition, it is preferable to add a dispersant to the aqueous medium. Examples of such a dispersant include organic dispersants such as partially saponified polyvinyl alcohol, polyacrylate, polyvinyl pyrrolidone, carboxymethyl cellulose, and methyl cellulose, magnesium pyrophosphate, calcium pyrophosphate, calcium phosphate, calcium carbonate, and magnesium phosphate. And inorganic dispersants such as magnesium carbonate and magnesium oxide. Of these, inorganic dispersants are preferred.
When an inorganic dispersant is used, it is preferable to use a surfactant in combination. Examples of such surfactants include dodecyl benzene sulfonic acid soda and α-olefin sulfonic acid soda.

The shape and structure of the polymerization vessel are not particularly limited as long as they are conventionally used for suspension polymerization of styrene monomers.
Further, the shape of the stirring blade is not particularly limited, and specifically, a paddle blade such as a V-shaped paddle blade, a fiddler blade, an inclined paddle blade, a flat paddle blade, a pull margin blade, a turbine blade, a fan turbine blade, etc. Examples include a turbine blade and a propeller blade such as a marine propeller blade. Of these stirring blades, paddle blades are preferred. The stirring blade may be a single-stage blade or a multi-stage blade. A baffle may be provided in the polymerization container.

The temperature of the aqueous medium when polymerizing the styrene monomer in the micropellet is not particularly limited, but is preferably in the range of −30 to + 20 ° C. of the melting point of the polyolefin resin to be used. More specifically, 70-150 degreeC is preferable and 80-145 degreeC is more preferable. Furthermore, the temperature of the aqueous medium may be a constant temperature from the start to the end of the polymerization of the styrenic monomer, or may be increased stepwise. When raising the temperature of an aqueous medium, it is preferable to make it raise at the temperature increase rate of 0.1-2 degree-C / min.
Furthermore, when using particles made of a crosslinked polyolefin resin, the crosslinking may be performed in advance before impregnating the styrene monomer, or while impregnating and polymerizing the styrene monomer in the micropellet. Or after impregnating and polymerizing a styrenic monomer in a micropellet.

Examples of the crosslinking agent used for crosslinking the polyolefin resin include 2,2-di-t-butylperoxybutane, dicumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxy. An organic peroxide such as hexane may be mentioned. In addition, a crosslinking agent may be individual or may be used together 2 or more types. Moreover, the usage-amount of a crosslinking agent has preferable 0.05-1.0 weight part normally with respect to 100 weight part of polyolefin resin particles (micro pellet).
Examples of the method of adding the crosslinking agent include a method of directly adding to the olefin resin particles, a method of adding the crosslinking agent after dissolving it in a solvent, a plasticizer or a styrene monomer, and a method of dispersing the crosslinking agent in water. The method of adding above etc. are mentioned. Among these, the method of adding after dissolving a crosslinking agent in a styrene-type monomer is preferable.
The particle diameter of the obtained composite resin particles is preferably about 0.2 to 2 mm, more preferably 0.5 to 1.8 mm.

(Expandable particles)
Expandable particles can be obtained by impregnating the above-mentioned composite resin particles with reduced odor with a foaming agent. Impregnation with the blowing agent can be performed by a method known per se. For example, the impregnation during the polymerization can be performed by performing the polymerization reaction in a sealed container and press-fitting a foaming agent into the container. The impregnation after the completion of the polymerization is performed by press-fitting a foaming agent in a sealed container.

Here, various known foaming agents can be used as the foaming agent. Examples thereof include propane, n-butane, isobutane, n-pentane, isopentane, industrial pentane, petroleum ether, cyclohexane, cyclopentane and the like alone or as a mixture. Of these, propane, n-butane, isobutane, n-pentane, isopentane and cyclopentane are preferred.
The expandable particles are obtained by a method of impregnating the composite resin particles with a foaming agent in an aqueous medium (wet impregnation method) or a method of impregnation in the absence of a medium (dry impregnation method). Here, the aqueous medium includes water and a mixed solvent of water and a water-soluble solvent (for example, alcohol).
The aqueous medium may contain a surfactant. Examples of the surfactant include an anionic surfactant and a nonionic surfactant.

Examples of anionic surfactants include alkyl sulfonates, alkyl benzene sulfonates, and alkyl phosphates. Among them, alkyl benzene sulfonates are preferable, and sodium dodecylbenzene sulfonate (sodium) is more preferable.
Nonionic surfactants include HLB values such as polyoxyethylene alkylamines (for example, polyoxyethylene laurylamine), polyethylene glycol fatty acid esters, alkyl diethanolamides, alkyl diethanol amines, alkyl monoethanol amines, polyalkylene glycol derivatives, etc. Up to 7 surfactants can be used. Among them, preferred are polyoxyethylene alkylamine, alkyldiethanolamine and alkylmonoethanolamine having an alkyl having 8 to 18 carbon atoms, more preferably 11 to 13, more preferably polyoxyethylene laurylamine. It is done.

(Pre-expanded particles and foamed molded product)
Next, a method for obtaining pre-expanded particles and further foamed molded products from expandable particles will be described.
Pre-expanded particles can be obtained by heating the expandable particles using a heating medium such as water vapor and pre-expanding them to a predetermined bulk density as necessary.
The pre-expanded particles preferably have a bulk multiple of 5 to 60 times (bulk density 0.016 to 0.2 g / cm ³ ). A more preferable bulk factor is 10 to 55 times. When the bulk factor is larger than 60 times, the closed cell ratio of the pre-expanded particles is lowered, and the strength of the foamed molded product obtained by foaming the pre-expanded particles may be lowered. On the other hand, if it is less than 5 times, the weight of the foamed molded product obtained by foaming the pre-foamed particles may increase.
Furthermore, the pre-expanded particles are filled in a mold of a molding machine, heated and subjected to secondary foaming, and the pre-expanded particles are fused and integrated with each other to obtain a foam-molded article having a desired shape. As the molding machine, there can be used an EPS molding machine or the like used when producing a foam molded body from polystyrene resin pre-foamed particles.

  The obtained foamed molded products include cushioning materials (cushion materials) for home appliances, electronic parts, various industrial materials, food containers, etc., automobile-related parts (for example, bumpers for vehicle bumpers, door interior cushioning materials, etc. For example, an impact energy absorbing material. In particular, from the viewpoint of obtaining a foamed molded article having a low odor, that is, an odor derived from the raw material and manufacturing method of the composite resin particles and reduced to an odor level value of 200 or less in a measurement atmosphere at 55 ° C. For example, it can also be suitably used for lower limb impact absorbing materials, floor raising materials, tool boxes, and the like.

Hereinafter, although an example is given and explained further, the present invention is not limited by these examples. Various measurement methods and production conditions described in the examples will be described below.
<Odor level value>
The odor level value is measured using the apparatus shown in FIG. In FIG. 1, 1 is a sample bottle, 2 is a sample (composite resin particle or foam molded article), 3 is an odor collection bottle, 4 is an odor extraction outlet, 5 is an odor circulation inlet, 6 is an odor sensor, and 7 is an odor introduction port. , 8 means an odor circulation outlet. As the odor sensor, a portable odor sensor XP-329IIIR manufactured by New Cosmos is used. Before measuring the odor level value, warm up the measuring device in the measurement environment, set the zero base, and then set the odor level value display to “0” before measurement.
(1) Composite resin particles 4 g of composite resin particles (sample 2) are placed in a sample bottle 1 having a capacity of 70 ml and covered. Sample bottle 1 is heated at 55 ° C. for 1 hour. After heating, the sample bottle 1 with the lid removed is placed in the odor collection bottle 3 having a capacity of 240 ml. The odor inlet 4 and the odor circulation inlet 5 provided in the odor collection bottle 3 are connected to the odor inlet 7 and the odor circulation outlet 8 of the odor sensor 6, respectively. After the connection, the odor level value of the composite resin particle is measured by the odor sensor 6, and the maximum value is set as the odor level value.
(2) Foam molded body The odor level value is measured in the same manner as the composite resin particles except that the foam molded body cut into 20 × 20 × 30 mm is used as sample 2 instead of 4 g of the composite resin particles.

<Softening temperature>
Measured according to the method described in JIS K7196 “Testing method for softening temperature of thermoplastic film and sheet by thermomechanical analysis”. That is, the modified polystyrene resin particles were hot-pressed at 180 ° C. for 5 minutes to produce a plate-like molded product having a thickness of 3 mm, and then a test piece having a length of 5 mm × width of 5 mm × thickness of 3 mm was cut out, and heat / stress / strain Using a measuring device (trade name “EXSTRAR TMA / SS6100” manufactured by SII Nano Technology, Inc.), with a needle insertion test mode (needle tip φ1 mm) and a load of 500 mN, the needle is applied to the test piece, and the heating rate is 5 Increase the temperature in degrees Celsius / min. In the TMA curve, extend the straight line portion that is recognized on the low temperature side from the start of the indenter (needle) to the high temperature side. The point of intersection with the extension to the penetration is the penetration temperature, and the penetration temperature is the softening temperature of the resin particles.
In addition, when there are two softening temperatures, the numerical value on the high temperature side is taken as the softening temperature.

<Pre-foaming conditions>
Introducing foamable resin particles into a normal pressure pre-foaming machine (SKK-70 manufactured by Sekisui Koki Co., Ltd. or PSX40 manufactured by Kasahara Kogyo Co., Ltd.) preheated with steam, and steaming to a setting of about 0.02 to 0.20 MPa while stirring. Introducing air, air is also supplied and foamed to a predetermined bulk density (bulk multiple) in about 2 to 3 minutes.

<In-mold molding conditions>
The pre-expanded particles are filled in the mold of the molding machine, heated and cooled under the following conditions, and then the molded foam is removed from the mold.
Molding machine: ACE-11QS manufactured by Sekisui Machinery Co., Ltd.
Mold dimension: 400mm (width) x 300mm (length) x 30mm (thickness)
Molding conditions Total heating time: 50 seconds Set steam pressure: 0.05-0.25 MPa
Cooling: Until the surface pressure is 0.001 MPa or less

<Bulk density and bulk expansion ratio of pre-expanded particles>
Pre-expanded particles are filled into a graduated cylinder to a scale of 500 cm ³ . When the graduated cylinder is visually observed from the horizontal direction and any pre-expanded particles reach a scale of 500 cm ³ , the filling of the pre-expanded particles into the graduated cylinder is terminated at that point.
Next, the mass of the pre-expanded particles filled in the measuring cylinder is weighed to the second significant figure after the decimal point, and the mass is defined as W (g).
Then, the bulk density of the pre-expanded particles is calculated by the following formula.
Bulk density (g / cm ³ ) = W / 500

<Density and expansion ratio of foamed molded product>
Measured by the method described in JIS K7222: 1999 "Foamed plastics and rubber-Measurement of apparent density".
A test piece of 50 cm ³ or more (100 cm ³ or more in the case of semi-hard and soft materials) is cut so as not to change the original cell structure of the material, its mass is measured, and it is 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 out from samples that had passed 72 hours or more after molding, and were subjected to atmospheric conditions of 23 ° C. ± 2 ° C. × 50% ± 5% or 27 ° C. ± 2 ° C. × 65% ± 5%. It has been left for more than an hour.

Example 1
a) Production of Modified Styrenic Resin Particles of Polyethylene Resin (PE) / Polystyrene Resin (PS) = 40/60 As a polyethylene resin, an ethylene-vinyl acetate copolymer (hereinafter referred to as EVA) (Nippon Polyethylene) Product name “LV-115”, ethylene component content: 96 wt%, melting point: 108 ° C., melt flow rate: 0.3 g / 10 min) 100 parts by weight and synthetic hydrous silicon dioxide 0.5 part by weight are extruded. It was supplied to a machine, melted and kneaded, and granulated by an underwater cutting method to obtain elliptic spherical (egg-shaped) EVA resin particles (polyolefin resin particles). The average weight of the EVA resin particles was 0.6 mg.
Next, 128 g of magnesium pyrophosphate and 32 g of sodium dodecylbenzenesulfonate were dispersed in 40 kg of water to obtain a dispersion medium.
16 kg of the above synthetic silicon dioxide-containing EVA resin particles were dispersed in a dispersion medium to obtain a suspension.
Further, 12.2 g of t-butyl peroxybenzoate as a polymerization initiator was dissolved in 6.4 kg of a styrene monomer to prepare a first styrene monomer.

The temperature of the suspension containing the EVA resin particles is adjusted to 60 ° C., and the styrene monomer is added in a fixed amount over 30 minutes, and then stirred for 1 hour, whereby the first styrene monomer is added to the EVA resin particles. Impregnated.
Next, the temperature of the reaction system was raised to 130 ° C., which is 23 ° C. higher than the melting point of EVA, and maintained for 3 hours to polymerize the styrene monomer in the EVA resin particles (first polymerization).
Next, the temperature of the reaction system was lowered to 90 ° C., and a second styrene monomer in which 33.4 g of t-butyl peroxybenzoate and 88 g of dicumyl peroxide were dissolved in 17.6 kg of styrene monomer as a polymerization initiator. Was continuously added dropwise at a rate of 4.4 kg per hour to polymerize (second polymerization) while impregnating the EVA resin particles with the second styrene monomer.
After completion of this dropping, the mixture was held at 90 ° C. for 1 hour, then heated to 143 ° C. and held for 3 hours to complete the polymerization, thereby obtaining modified styrene resin particles.
It was 105 degreeC when the softening temperature of the obtained modified styrene resin particle was measured.
Further, from the photograph of the cross section of the modified styrene resin particles, the particles had a co-continuous structure in which bands made of polystyrene resin were continuous.

b) Reduction of odor Next, 70 kg of the modified styrene resin particles prepared by the above method was modified styrene using a fluidized bed dryer (model: SGD-3, 1 m ² area of the pan) manufactured by Okawara Seisakusho. The gas (air) at 92 ° C., which is 13 ° C. lower than the softening temperature T ° C. of the resin particles, was introduced into the apparatus being blown from the lower portion at a speed of 1.2 m / second, and treated for 6 hours to reduce odor. A fresh gas was always used at a ventilation air volume of 72 m ³ / min.
Next, it was cooled to room temperature, and the modified styrene resin particles were taken out from the particle size layer dryer to obtain modified polystyrene resin particles with reduced odor.

c) Prefoaming Subsequently, 100 parts by weight of modified resin particles, 1.0 part by weight of water, 0.15 part by weight of stearic acid monoglyceride and 0.5 parts of diisobutyl adipate were added to a pressure-resistant V-type rotary mixer having an internal volume of 1 m ^3. 14 parts by weight of butane (n-butane: i-butane = 7: 3) was press-fitted at room temperature while supplying and rotating the parts by weight. Then, the inside of the rotary mixer was heated to 70 ° C. and held for 4 hours, and then cooled to 25 ° C. to obtain expandable resin particles.
The obtained expandable resin particles were immediately supplied to a pre-foaming machine (trade name “SKK-70” manufactured by Sekisui Koki Seisakusho Co., Ltd.) and pre-foamed using steam at a pressure of 0.02 MPa to obtain a bulk density of 0.033 g. / Cm ³ of pre-expanded particles were obtained.

d) Foam molding Next, the pre-foamed particles were allowed to stand at room temperature for 7 days and then filled into a mold of a molding machine. Then, water vapor was supplied into the mold, and the pre-expanded particles were subjected to foam molding to produce a foam molded body having a rectangular parallelepiped shape of 0.033 g / cm ³ in length of 400 mm × width of 300 mm × height of 30 mm. Both the fusion rate and appearance of the obtained foamed molded article were good.
Various measurement results are shown in Table 1.

Example 2
a) Production of Modified Styrene Resin Particles of Polyethylene Resin (PE) / Polystyrene Resin (PS) = 30/70 In the same manner as in Example 1, as a polyethylene resin, EVA (trade name “LV” manufactured by Nippon Polyethylene Co., Ltd.) -115 ") 100 parts by weight and 0.5 parts by weight of synthetic hydrous silicon dioxide are fed to an extruder, melted and mixed, granulated by an underwater cutting method, and oval (egg) EVA resin particles (polyolefin type) Resin particles) were obtained. The average weight of the EVA resin particles was 0.6 mg.
Next, 128 g of magnesium pyrophosphate and 32 g of sodium dodecylbenzenesulfonate were dispersed in 40 kg of water to obtain a dispersion medium.
12 kg of the above-mentioned synthetic silicon dioxide-containing EVA resin particles were dispersed in a dispersion medium to obtain a suspension.

Furthermore, 9.5 g of t-butyl peroxybenzoate as a polymerization initiator was dissolved in 5.0 kg of a styrene monomer to prepare a first styrene monomer.
The temperature of the suspension containing the EVA resin particles is adjusted to 60 ° C., and the styrene monomer is added in a fixed amount over 30 minutes, and then stirred for 1 hour, whereby the first styrene monomer is added to the EVA resin particles. Impregnated.
Next, the temperature of the reaction system was raised to 130 ° C., which is 23 ° C. higher than the melting point of EVA, and maintained for 3 hours to polymerize the styrene monomer in the EVA resin particles (first polymerization).
Next, the temperature of the reaction system was lowered to 90 ° C., and a second styrene monomer in which 39.2 g of t-butyl peroxybenzoate and 66 g of dicumyl peroxide were dissolved in 23.0 kg of styrene monomer as a polymerization initiator. Was continuously added dropwise at a rate of 4.4 kg per hour to polymerize (second polymerization) while impregnating the EVA resin particles with the second styrene monomer.
After completion of this dropping, the mixture was held at 90 ° C. for 1 hour, then heated to 143 ° C. and held for 3 hours to complete the polymerization, thereby obtaining modified styrene resin particles.
The softening temperature of the obtained modified styrene resin particles was measured and found to be 107 ° C.
A photograph of the cross section of the modified styrene resin particles is shown in FIG. 2 (12800 times). The particles had a co-continuous structure in which bands made of polystyrene resin were continuous.
b) to d) Odor Reduction to Foam Molding Step a) and subsequent steps were performed in the same manner as in Example 1.
Various measurement results are shown in Table 1.

Example 3
As a polyethylene resin, EVA (trade name “LV-211” manufactured by Nippon Polyethylene Co., Ltd., ethylene-derived component amount: 94% by weight, melting point: 103 ° C., melt flow rate: 0.3 g / 10 min) 100 parts by weight, synthetic water content 0.5 parts by weight of silicon dioxide and 7.7 parts by weight of carbon black masterbatch (DOE 28E-40) containing 40% by weight are fed into an extruder, melted and mixed, granulated by an underwater cutting method, and then elliptical. Spherical (egg-like) EVA resin particles (polyolefin resin particles) were obtained. The average weight of the EVA resin particles was 0.6 mg.
Next, 128 g of magnesium pyrophosphate and 32 g of sodium dodecylbenzenesulfonate were dispersed in 40 kg of water to obtain a dispersion medium.
12 kg of the above-mentioned synthetic silicon dioxide-containing EVA resin particles were dispersed in a dispersion medium to obtain a suspension.
After the first polymerization in the same manner as in Example 1, the temperature of the reaction system was lowered to 115 ° C., and 84 g of dicumyl peroxide was dissolved in 11.6 kg of styrene monomer as a polymerization initiator. The second styrene monomer was continuously added dropwise at a rate of 4.4 kg per hour, thereby polymerizing the second styrene monomer while impregnating the EVA resin particles (second polymerization).

After the completion of the dropping, the mixture was held at 115 ° C. for 1 hour, then heated to 140 ° C. and held for 3 hours to complete the polymerization, thereby obtaining modified styrene resin particles.
It was 102 degreeC when the softening temperature of the obtained modified styrene resin particle was measured.
A photograph of the cross section of the modified styrene resin particles is shown in FIG. 3 (12800 times). The particles had a structure in which polystyrene resin particles were dispersed.
b) to d) Reduction of odor to foam molding As in Example 1, except that the obtained modified styrene resin particles were used, the processing temperature for odor reduction was 90 ° C., and the processing time was 5 hours. A foamed molded product with reduced odor was obtained.
Various measurement results are shown in Table 1.

Example 4
a) Production of modified styrene resin particles of polyethylene resin (PE) / polystyrene resin (PS) = 20/80 As polyethylene resin, LLDPE (trade name “NF-464A” manufactured by Nippon Polyethylene Co., Ltd., melting point: 124 C., melt flow rate: 2 g / 10 min) 100 parts by weight and 0.5 parts by weight of synthetic hydrous silicon dioxide are supplied to an extruder, melted and kneaded, and granulated by an underwater cutting method to form an oval (egg-like) shape. LLDPE resin particles (polyethylene resin particles) were obtained. The average weight of the LLDPE resin particles was 0.6 mg.
Next, 128 g of magnesium pyrophosphate and 32 g of sodium dodecylbenzenesulfonate were dispersed in 40 kg of water to obtain a dispersion medium.
8 kg of the above synthetic silicon dioxide-containing LLDPE resin particles were dispersed in a dispersion medium to obtain a suspension.

Further, 7.6 g of t-butyl peroxybenzoate as a polymerization initiator was dissolved in 4 kg of styrene monomer to prepare a first styrene monomer.
The temperature of the suspension containing the LLDPE resin particles is adjusted to 60 ° C., and the styrene monomer is added in a fixed amount over 30 minutes, and then stirred for 1 hour, whereby the first styrene monomer is added to the LLDPE resin particles. Impregnated.
Next, the temperature of the reaction system was raised to 135 ° C., which is 11 ° C. higher than the melting point of LLDPE, and maintained for 3 hours to polymerize the styrene monomer in the LLDPE resin particles (first polymerization).

Next, the temperature of the reaction system was lowered to 115 ° C., and a second styrene monomer obtained by dissolving 53.2 g of t-butyl peroxybenzoate as a polymerization initiator in 28 kg of styrene monomer was 4.6 kg per hour. By continuously dropping at a ratio, polymerization (second polymerization) was performed while impregnating the second styrene monomer into the LLDPE resin particles.
After the completion of the dropping, the mixture was held at 115 ° C. for 1 hour, then heated to 140 ° C. and held for 3 hours to complete the polymerization, thereby obtaining modified styrene resin particles.
The softening temperature of the obtained modified styrene resin particles was measured and found to be 107 ° C.
Moreover, the photograph of the cross section of this modified styrene resin particle is shown in FIG. 4 (12800 times). The particles had a structure in which polystyrene resin particles were dispersed.
b) to d) Odor Reduction to Foam Molding The obtained modified styrene resin particles were used, and the treatment temperature for odor reduction was 92 ° C. and the treatment time was 4 hours. A foamed molded product with reduced odor was obtained.
Various measurement results are shown in Table 1.

Example 5
a) Production of Modified Styrenic Resin Particles of Polyethylene Resin (PE) / Polystyrene Resin (PS) = 30/70 As a polyethylene resin, LLDPE (trade name “NF-464A” manufactured by Nippon Polyethylene Co., Ltd., melting point: 124 C., melt flow rate: 2 g / 10 min) 100 parts by weight, synthetic water-containing silicon dioxide 0.5 part by weight and 40% by weight of carbon black masterbatch (28E-40 manufactured by DOW) 7.7 parts by weight in the extruder The mixture was melted and mixed, and granulated by an underwater cutting method to obtain elliptical (egg-like) LLDPE resin particles (polyethylene resin particles). The average weight of the LLDPE resin particles was 0.6 mg.
Next, 128 g of magnesium pyrophosphate and 32 g of sodium dodecylbenzenesulfonate were dispersed in 40 kg of water to obtain a dispersion medium.
A suspension was obtained by dispersing 12 kg of the above-mentioned synthetic silicon dioxide-containing LLDPE resin particles in a dispersion medium.

Further, 11.4 g of t-butyl peroxybenzoate as a polymerization initiator was dissolved in 6 kg of styrene monomer to prepare a first styrene monomer.
The temperature of the suspension containing the LLDPE resin particles is adjusted to 60 ° C., and the styrene monomer is added in a fixed amount over 30 minutes, and then stirred for 1 hour, whereby the first styrene monomer is added to the LLDPE resin particles. Impregnated.
Next, the temperature of the reaction system was raised to 135 ° C., which is 11 ° C. higher than the melting point of LLDPE, and maintained for 3 hours to polymerize the styrene monomer in the LLDPE resin particles (first polymerization).

Next, the temperature of the reaction system was lowered to 115 ° C., and a second styrene monomer obtained by dissolving 41.8 g of t-butyl peroxybenzoate as a polymerization initiator in 22 kg of styrene monomer was 4.6 kg per hour. By continuously dropping at a ratio, polymerization (second polymerization) was performed while impregnating the second styrene monomer into the LLDPE resin particles.
After the completion of the dropping, the mixture was held at 115 ° C. for 1 hour, then heated to 140 ° C. and held for 3 hours to complete the polymerization, thereby obtaining modified styrene resin particles.
The softening temperature of the obtained modified styrene resin particles was measured and found to be 107 ° C.
Moreover, the photograph of the cross section of this modified styrene resin particle is shown in FIG. 4 (12800 times). The particles had a structure in which polystyrene resin particles were dispersed.
b) to d) Odor Reduction to Foam Molding The obtained modified styrene resin particles were used, and the treatment temperature for odor reduction was 92 ° C. and the treatment time was 4 hours. A foamed molded product with reduced odor was obtained.
Various measurement results are shown in Table 1.

Example 6
a) Production of Modified Styrene Resin Particles of Polypropylene Resin (PP) / Polystyrene Resin (PS) = 40/60 As polypropylene resin, trade name “F-744NP” (melting point: 140 ° C., manufactured by Prime Polymer Co., Ltd.) Melt flow rate: 7.0 g / 10 min) 100 parts by weight are supplied to an extruder, melt kneaded, granulated by an underwater cutting method, and oval (egg-like) polypropylene resin particles (polyolefin resin particles) Got. The average weight of the polypropylene resin particles at this time was 0.8 mg.
Next, 400 g of magnesium pyrophosphate and 10 g of sodium dodecylbenzenesulfonate were dispersed in 40 kg of water in a 100 L autoclave equipped with a stirrer to obtain a dispersion medium.
A suspension was obtained by dispersing 16 kg of the synthetic polypropylene resin particles in a dispersion medium.

Further, 16 g of dicumyl peroxide as a polymerization initiator was dissolved in 8.0 kg of styrene monomer to prepare a first styrene monomer.
The temperature of the suspension containing the polypropylene system is adjusted to 60 ° C., and the styrene monomer is added in a fixed amount over 30 minutes, and then stirred for 1 hour, whereby the first styrene monomer is added to the polypropylene resin particles. Impregnated.
Next, the temperature of the reaction system was raised to 140 ° C., which is the same as the melting point of the polypropylene resin, and maintained for 2 hours to polymerize the styrene monomer in the polypropylene resin particles (first polymerization).

Next, the temperature of the reaction system is lowered to 120 ° C., and a second styrene monomer in which 72 g of dicumyl peroxide is dissolved in 16 kg of styrene monomer as a polymerization initiator is continuously dropped at a rate of 4 kg per hour. Thus, the second styrene monomer was polymerized (second polymerization) while impregnating the polypropylene resin particles.
After completion of the dropping, the mixture was held at 120 ° C. for 1 hour, then heated to 143 ° C. and held for 3 hours to complete the polymerization to obtain modified styrene resin particles.
It was 126 degreeC when the softening temperature of the obtained modified styrene resin particle was measured.
Further, from the photograph of the cross section of the modified styrene resin particles, the particles had a co-continuous structure in which bands made of polystyrene resin were continuous.

b) Reduction of Odor Next, 18 kg of the modified styrene resin particles produced by the above method was replaced with the modified styrene resin particles using a fluidized bed drying apparatus (model: FB-0.5) manufactured by Okawara Seisakusho. A gas (air) at 102 ° C., which is 24 ° C. lower than the softening temperature T ° C., was introduced into the apparatus blown from the lower part at a speed of 1.2 m / second, and treated for 4 hours to reduce odor. A fresh gas was always used at a ventilation air volume of 72 m ³ / min.
Next, it was cooled to room temperature, and the modified styrene resin particles were taken out from the particle size layer dryer to obtain modified polystyrene resin particles with reduced odor.

c) Prefoaming Subsequently, 2 kg of modified styrene resin particles and 2 L of water are put into a 5 L autoclave with stirring, and 15 parts by weight of butane (n-butane: i-butane = 7: 3) is injected at room temperature as a blowing agent. did. After the injection, the temperature was raised to 70 ° C. and stirring was continued for 4 hours.
Then, after cooling to room temperature, it was taken out from the 5 L autoclave, dehydrated and dried, and then foamed modified styrene resin particles were obtained.
The obtained expandable resin particles were immediately supplied to a pre-foaming machine (trade name “PSX40” manufactured by Kasahara Kogyo Co., Ltd.) and pre-foamed using water vapor at a pressure of 0.15 MPa to obtain a bulk density of 0.033 g / cm ³ . Pre-expanded particles were obtained.

d) Foam molding Next, the pre-foamed particles were allowed to stand at room temperature for 7 days and then filled into a mold of a molding machine. Then, water vapor was supplied into the mold, and the pre-expanded particles were subjected to foam molding to produce a foam molded body having a rectangular parallelepiped shape of 0.033 g / cm ³ in length of 400 mm × width of 300 mm × height of 30 mm. Both the fusion rate and appearance of the obtained foamed molded article were good.
Various measurement results are shown in Table 1.

Example 7
As a polypropylene resin, 100 parts by weight of Prime Polymer's trade name “F-744NP” and 12.5 parts by weight of 45% by weight carbon black masterbatch (PP-RM10H381 made by Dainichi Seika Kogyo Co., Ltd.) are supplied to the extruder. The mixture was melt-kneaded and granulated by an underwater cutting method to obtain elliptical (egg-like) polypropylene resin particles (polyolefin resin particles). The average weight of the polypropylene resin particles at this time was 0.8 mg.
A foamed molded product was obtained in the same manner as in Example 6 except that the obtained polypropylene resin particles were used.
Various measurement results are shown in Table 1.

Example 8
To reduce odor, the total gas volume blown from the bottom to the fluidized bed dryer is 82 m ³ / min, and the total gas volume is 78 m ³ / min (ventilation air volume). A foamed molded article was obtained in the same manner as in Example 7, except that the air volume of the circulating gas introduced from the lower part of the apparatus was changed to 4 m ³ / min (circulating air volume).
Various measurement results are shown in Table 1.

Example 9
To reduce odor, the total air volume of the gas blown from the bottom to the fluidized bed dryer is 72 m ³ / min, and the total gas volume is 8 m ³ / min (ventilation air volume). A foamed molded article was obtained in the same manner as in Example 7 except that the flow rate of the circulating gas introduced from the lower part of the apparatus was 64 m ³ / min (circulation flow rate).
Various measurement results are shown in Table 1.

Comparative Example 1
A foamed molded article was obtained in the same manner as in Example 1 except that the modified polystyrene resin particles obtained in Example 1 were not subjected to odor reduction treatment.
Various measurement results are shown in Table 2.
Comparative Example 2
A foam molded article was obtained in the same manner as in Example 1 except that the treatment temperature was 60 ° C. and the treatment time was 12 hours.
Various measurement results are shown in Table 2.
Comparative Example 3
An attempt was made to reduce odor in the same manner as in Example 1 except that the treatment temperature was set to 97 ° C. However, the treatment temperature was too high with respect to the softening temperature of the modified styrene resin particles. Processing could not be continued because they were connected.
Various measurement results are shown in Table 2.

  From Examples 1-9 and Comparative Examples 1-3, when the softening temperature of the composite resin particles is T ° C, the composite resin particles are blown while blowing a gas of (T-40) to (T-10) ° C from the bottom of the container. It can be seen that when it is flowed, the odor contained in the composite resin particles can be efficiently reduced, and as a result, a foam molded article having a low level of odor content can be obtained from the resin particles.

1 is a sample bottle, 2 is a sample (composite resin particle or foam molding), 3 is an odor collection bottle, 4 is an odor extraction outlet, 5 is an odor circulation inlet, 6 is an odor sensor, 7 is an odor introduction port, and 8 is an odor Circulation outlet

Claims (12)

  A composite resin particle for producing a foamed molded article containing a polyolefin resin and a polystyrene resin was blown from the lower part of the container into a gas (T-40) ° C. to (T-10) ° C. (T In the composite resin particles, wherein the odor in the composite resin particles is reduced to an odor level value of 200 or less in a measurement atmosphere of 55 ° C. by flowing at a softening temperature of the composite resin particles. Odor reduction method.   The gas blown from the lower part of the container is discharged outside the container, and again blown and circulated together with a new gas from the lower part of the container, and the circulating gas contains 4% by volume or more of the new gas. The odor reduction method in the composite resin particle as described in 1.   The method for reducing odor in composite resin particles according to claim 1 or 2, wherein the polyolefin-based resin is a polyethylene-based resin, and the gas is blown at (T-30) ° C to (T-10) ° C.   The method for reducing odor in composite resin particles according to claim 1 or 2, wherein the polyolefin resin is a polypropylene resin, and the gas is blown at (T-40) ° C to (T-15) ° C.   The method for reducing odor in composite resin particles according to any one of claims 1 to 4, wherein the composite resin particles are placed in a container into which gas is blown from below.   The method for reducing odor in composite resin particles according to any one of claims 1 to 5, wherein the gas is blown from the bottom of the container at a flow rate of 0.5 to 2.0 m / sec.   Composite resin particles with reduced odor obtained by the method according to any one of claims 1 to 6.   The composite resin particle according to claim 7, wherein the composite resin particle contains carbon black.   Expandable particles obtained by impregnating the composite resin particles according to claim 7 or 8 with a foaming agent.   Pre-expanded particles obtained by pre-expanding the expandable particles of claim 9.   A foamed molded product obtained by in-mold molding of the pre-expanded particles of claim 10 and having an odor level value of 200 or less in a measurement atmosphere at 55 ° C.   An automotive interior material derived from the foamed molded article according to claim 11.