KR20120079062A - Process for production of expandable resin particles, pre-expanded beads, and products of expansion molding - Google Patents

Abstract

The manufacturing method of foamable resin particle which obtains foamable resin particle which has ultraviolet-ray shielding property by making the resin particle which can become foamable resin particle impregnate a foaming agent, and making a contact with said resin particle an ultraviolet absorber.

Description

TECHNICAL FOR PRODUCTION OF EXPANDABLE RESIN PARTICLES, PRE-EXPANDED BEADS, AND PRODUCTS OF EXPANSION MOLDING

The present invention relates to a method for producing expandable resin particles, prefoamed particles and expanded molded article. In more detail, this invention relates to the manufacturing method, pre-expanded particle | grain, and foamed molded object of the ultraviolet-ray absorbing function imparted. The foamed molded article obtained from the expandable resin particles of the present invention is suitable for a container for transporting and / or storing an electrical product that may be damaged by ultraviolet rays.

Various products or parts thereof are put in containers to be protected from damage during transportation or storage. A container made of a resin is usually used for such a container, and a container made of a foamed molded article having a buffer against shock is particularly suitably used.

By the way, in the case of a product, the manufacturing place and sales place may be separated. In the case of parts, the place where a part is manufactured and the place where it is assembled to a product may be separated. With the recent globalization of the economy, these places often cross borders. For this reason, the transportation or storage of a product or a part may be extended for a long time. For example, it is known that electrical appliances deteriorate by irradiation of ultraviolet rays. In the case of long-term transportation or storage, the chances of exposure of electrical appliances to ultraviolet rays increase. Accordingly, the container is required to provide excellent shock resistance and shield against ultraviolet rays exposed during transportation and storage.

In order to manufacture the foamed molded article to which the ultraviolet absorber is applied, Japanese Laid-Open Patent Publication No. 2002-155161 (Patent Document 1) can be cited as a document that examines a method of previously presenting a ultraviolet absorber in a resin component. In this document, mixing of the resin component and the ultraviolet absorber is carried out by an extruder, and the extruded pellets are impregnated with a blowing agent to obtain expandable resin particles.

Japanese Patent Application Laid-Open No. 2002-155161

This publication uses a ultraviolet absorber for the purpose of improving weather resistance. In addition, the ultraviolet absorber is mixed with the resin component by an extruder. For this reason, the foamed molded article obtained can shield a certain amount of ultraviolet rays. However, there has been a demand for providing a foamed molded article having an impact resistance and a foamed resin particle for producing the same, which can be efficiently and simply and easily mixed with a resin component to further improve ultraviolet shielding properties.

As a manufacturing method of a resin particle, various methods, such as an extrusion method, suspension polymerization method, an emulsion polymerization method, are known, for example. As a result of examining the addition time of an ultraviolet absorber, the present inventors found that the addition time of an ultraviolet absorber is not impregnated at the time of manufacture of a resin particle but at the time of impregnation of a foaming agent, and can provide a foamed molded body which combines the shielding and impact resistance of an ultraviolet ray in a high dimension. The present invention was surprisingly found out that a foamable resin particle can be obtained.

Thus, according to this invention, when impregnating a foaming agent with the resin particle which may become foamable resin particle, the manufacturing method of foamable resin particle which obtains foamable resin particle which has ultraviolet-shielding property by making a contact with an ultraviolet absorber to the said resin particle is provided.

Moreover, according to this invention, the prefoamed particle obtained by prefoaming the expandable resin particle obtained by the said method by 5 to 60 times of volume multiples is provided.

Moreover, according to this invention, it is a foamed molded object obtained from the foamable resin particle containing a ultraviolet absorber,

The foamed molded article is provided with a molded foam having a transmittance of light of 365 nm wavelength of 3% or less in a sample cut to a thickness of 5 mm from the skin.

According to the present invention, when the contact time between the resin particles and the ultraviolet absorber is impregnated with the blowing agent, the ultraviolet absorber can be easily and efficiently absorbed into the resin particles. Therefore, according to this invention, the foamable resin particle which can provide the foam molding which has the shielding of the ultraviolet-ray and impact resistance can be obtained.

Moreover, when a ultraviolet absorber is a benzotriazole type or a benzophenone type ultraviolet absorber and 0.01-0.5 weight part is used with respect to 100 weight part of resin particles, foamable resin particle which can provide the foamed molded object which further improved the shielding of an ultraviolet-ray. Can be obtained.

Furthermore, when the resin particles are resin particles containing a polyolefin resin and a polystyrene resin, a foamed molded article excellent in impact resistance and crack resistance is provided while maintaining shielding of ultraviolet rays even when the polystyrene resin component is increased to improve bead life. Expandable resin particles can be obtained.

Further, when the resin particles are resin particles containing 100 parts by weight of polyolefin resin and 120 to 560 parts by weight of polystyrene resin, the dimension of improvement of bead life, impact resistance and crack resistance is maintained while maintaining shielding of ultraviolet rays. Compatible foamable resin particles can be obtained.

The pre-expanded particles obtained by pre-expanding the expandable resin particles in a volume multiple of 5 to 60 times are pre-expanded particles capable of providing a foamed molded article having a high degree of shielding and impact resistance.

The foamed molded article of the present invention has a high degree of shielding and impact resistance of ultraviolet rays.

BRIEF DESCRIPTION OF THE DRAWINGS It is a graph which shows the relationship of the wavelength and the transmittance | permeation of irradiation light with respect to the foamed molded object of Example 1.
2 is a graph showing the relationship between the wavelength of the irradiated light and the transmittance of the foamed molded article of Example 2. FIG.
3 is a graph showing the relationship between the wavelength of the irradiated light and the transmittance with respect to the expanded molded article of Example 3. FIG.
4 is a graph showing the relationship between the wavelength of the irradiated light and the transmittance with respect to the expanded molded article of Example 4. FIG.
5 is a graph showing the relationship between the wavelength of the irradiated light and the transmittance with respect to the expanded molded article of Comparative Example 1. FIG.
6 is a graph showing the relationship between the wavelength of the irradiated light and the transmittance with respect to the expanded molded article of Example 7. FIG.
It is a schematic diagram of the measuring apparatus of the ultraviolet transmittance of foamed molded object.
It is a graph which shows the radiation degree for every wavelength of the foamed molded object of UV light, Example 1, and the comparative example 1. FIG.

(Foamable resin particles)

In the manufacturing method of foamable resin particle, contact of a resin particle and a ultraviolet absorber is performed at the time of impregnation of a foaming agent. Here, contact of the ultraviolet absorber with the resin particles is performed by the presence of the ultraviolet absorber in the vicinity of the resin particles during impregnation of the blowing agent. A ultraviolet absorber may be added simultaneously with the impregnation of a blowing agent, and may be added to the system in which resin particle exists before impregnation of a blowing agent.

(1) resin particles

The resin particles are not particularly limited as long as they are particles capable of becoming expandable resin particles, in other words, particles capable of impregnating a blowing agent. For example, the resin particle which consists of resin components, such as a polyolefin resin, a polystyrene resin, and a mixture of these resin, is mentioned. Moreover, the rubber component (polybutadiene, butadiene-styrene copolymer, etc.) may be contained in the resin component in the range which does not prevent the effect of this invention.

It does not specifically limit as polyolefin resin, Well-known resin can be used. Moreover, polyolefin resin may be bridge | crosslinking. For example, polyethylene type resins, such as a branched low density polyethylene, a linear low density polyethylene, a medium density polyethylene, a high density polyethylene, an ethylene-vinyl acetate copolymer, an ethylene-methyl methacrylate copolymer, the crosslinked material of these polymers, and propylene only And polypropylene resins such as polymers, ethylene-propylene random copolymers, propylene-1-butene copolymers, and ethylene-propylene-butene random copolymers. Among the above examples, the low density is preferably 0.91 to 0.94 g / cm 3, and more preferably 0.91 to 0.93 g / cm 3. It is preferable that it is 0.95-0.97g / cm <3>, and, as for high density, it is more preferable that it is 0.95-0.96g / cm <3>. Medium density is the intermediate density between these low and high density.

As polystyrene resin, it is a copolymer of the other monomer which has polystyrene or styrene as a main component, and is copolymerizable with styrene. A main component means that styrene occupies 70 weight% or more of all monomers. Other monomers include α-methyl styrene, p-methyl styrene, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, acrylic acid alkyl ester, methacrylic acid alkyl ester, divinylbenzene, polyethylene glycol dimethacrylate, and the like. This is illustrated. In the example, alkyl means alkyl having 1 to 8 carbons.

It is preferable that a resin component contains polyolefin resin and polystyrene resin simultaneously. In this case, the polyolefin resin used is preferably branched low density polyethylene, linear low density polyethylene or ethylene-vinyl acetate copolymer, and the polystyrene resin is polystyrene, styrene-acrylic acid alkyl ester copolymer or styrene-methacrylate alkyl. It is preferable that it is an ester copolymer.

It is preferable that polystyrene resin is contained in 120-560 weight part with respect to 100 weight part of polyolefin resin particles in a resin particle.

When content of polystyrene resin is more than 560 weight part, the crack resistance of a foamed molded object may fall. On the other hand, if it is less than 120 parts by weight, the crack resistance is greatly improved, but there is a tendency that the monoacid of the blowing agent from the surface of the expandable resin particles is faster. For this reason, the bead life of foamable resin particle may become short when the retention property of a foaming agent falls. Content of more preferable polystyrene resin is 140-450 weight part, and still more preferable content is 150-400 weight part.

As a method of simultaneously including a polyolefin resin and a polystyrene resin, for example, a method in which both resins are kneaded in an extruder, particles made of polyolefin resin are impregnated with a styrene monomer in an aqueous medium, and then the monomer is polymerized. And the like. Among these, the latter method is preferable from the viewpoint of being able to mix both resins more uniformly and to obtain particles closer to the spherical shape. Here, the resin particle obtained by the latter method is called the composite resin particle which consists of polyolefin and polystyrene.

The latter method will be described below.

First, the polyolefin resin particle as a raw material can be obtained by a well-known method. For example, the polyolefin resin particle can be produced by melt-extruding a polyolefin resin first using an extruder, and then granulating by an underwater cut, a strand cut, etc. The shape of the polyolefin resin normally used is, for example, a spherical shape, an elliptic spherical shape (egg shape), a columnar shape, a columnar shape, a pellet shape, or a granular shape. Hereinafter, polyolefin resin particles are also referred to as micropellets.

The radical olefin may be contained in polyolefin resin. The radical scavenger may be previously added to the polyolefin resin or may be added simultaneously with melt extrusion. The radical complementing agent is a compound having a function of trapping radicals such as a polymerization inhibitor (including a polymerization inhibitor), a chain transfer agent, an antioxidant, a hindered amine light stabilizer, and the like, which is difficult to dissolve in water.

It is preferable that it is 0.005-0.5 weight part with respect to 100 weight part of polyolefin resins as an usage-amount of a radical complement agent.

The polyolefin-based resin particles may also be foamed nucleating agents such as talc, calcium silicate, calcium stearate, synthetic or natural silicon dioxide, ethylene bis stearate amide, methacrylic acid ester copolymers, and triallyl isocyanurate 6 It may contain flame retardants such as bromide, colorants such as carbon black, iron oxide and graphite.

Next, polyolefin resin particle is disperse | distributed in the aqueous medium in a polymerization container, and it superposes | polymerizes, impregnating a styrene monomer to polyolefin resin particle.

As an aqueous medium, the mixed medium of water, water, and a water-soluble solvent (for example, alcohol) is mentioned.

Styrene-based monomers can be used both styrene and substituted styrene (substituents include lower alkyl, halogen atoms (especially chlorine atoms) and the like). The styrene monomer may be a mixture of styrene and substituted styrene, a small amount of other monomers copolymerizable with styrene (for example, acrylonitrile, methacrylic acid alkyl ester (about 1 to 8 carbon atoms in the alkyl moiety), and maleic acid to mono); And mixtures of polyalkyl (about 1 to 4 carbon atoms in the alkyl moiety), divinylbenzene, mono to diacrylic acid to methacrylic acid esters of ethylene glycol, maleic anhydride, N-phenylmaleide, and the like. It is preferable that styrene occupies the uppermost amount (for example, 50 weight% or more) in these mixtures.

Moreover, you may add solvent (plasticizer), such as toluene, xylene, cyclohexane, ethyl acetate, and dioctyl adipic acid, to a styrene-type monomer.

Impregnation of the styrene monomer to the polyolefin resin particles may be carried out while polymerization, or may be carried out before starting the polymerization. Among these, it is preferable to carry out polymerization. Moreover, when superposing | polymerizing after impregnation, superposition | polymerization of a styrene-type monomer in the surface vicinity of polyolefin resin particle tends to occur. Moreover, the styrene monomer which was not impregnated in polyolefin resin particle is easy to superpose | polymerize independently. As a result, a large amount of particulate polystyrene resin particles may be produced.

An oil-soluble radical polymerization initiator can be used for superposition | polymerization of a styrene-type monomer. As this polymerization initiator, the polymerization initiator generally used for superposition | polymerization of a styrene-type monomer can be used.

Various methods are mentioned as a method of adding a polymerization initiator to the aqueous medium in a polymerization container. For example,

(1) a method in which a polymerization initiator is dissolved and contained in a styrene monomer in a container different from the polymerization vessel, and the styrene monomer is supplied into the polymerization vessel;

(2) A solution is prepared by dissolving a 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 a styrene monomer into a polymerization vessel,

(3) The dispersion liquid which disperse | distributed the polymerization initiator to the aqueous medium is produced. Method of supplying this dispersion liquid and a styrene-based monomer into a polymerization vessel

And the like.

As for the usage-amount of the said polymerization initiator, it is preferable to add 0.02-2.0 weight% of the total used amount of a styrene-type monomer normally.

It is preferable to dissolve a water-soluble radical polymerization inhibitor in an aqueous medium. The water-soluble radical polymerization inhibitor not only inhibits the polymerization of the styrene monomer on the surface of the polyolefin resin particles, but also prevents the polymerization of the styrene monomer floating in the aqueous medium alone, thereby reducing the generation of fine particles of the polystyrene resin. Because.

As a water-soluble radical polymerization inhibitor, the polymerization inhibitor which melt | dissolves 1g or more with respect to 100g of water can be used.

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 which is an aqueous medium.

Moreover, it is preferable to add dispersing agents, such as an inorganic type dispersing agent, and surfactant in the said aqueous medium.

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. For example, the polymerization vessel provided with the stirring blade is used suitably.

Moreover, there is no restriction | limiting in particular also about the shape of a stirring blade, Specifically, a turbine, such as paddle wings, a turbine blade, a fan turbine blade, such as a V-shaped paddle wing, a paddle wing, an inclined paddle wing, a flat paddle wing, and a full margin wing. Wing, propeller wings, such as a marine propeller wing, etc. are mentioned. Among these stirring vanes, paddle vanes are preferred. The stirring blade may be a single wing or a multistage wing. You may provide a baffle plate in a polymerization container.

Moreover, although the temperature of the aqueous medium at the time of superposing | polymerizing a styrene-type monomer in a micropellet is not specifically limited, It is preferable that it is the range of -30-20 degreeC of melting | fusing point of the polyolefin resin to be used. More specifically, 70-140 degreeC is preferable and 80-135 degreeC is more preferable. The temperature of the aqueous medium may be a constant temperature during the polymerization start to the end of the styrene monomer, or may be raised step by step. When raising the temperature of an aqueous medium, it is preferable to raise at the temperature increase rate of 0.1-2 degree-C / min.

In addition, when using the particle | grain which consists of crosslinked polyolefin resin, crosslinking may be performed before impregnating a styrene monomer, may be performed while impregnating and polymerizing a styrene monomer in a micropellet, and styrene in a micropellet. You may implement after impregnating and superposing | polymerizing a system monomer.

As a crosslinking agent used for the crosslinking of polyolefin resin, for example, 2, 2- di- t-butyl peroxy butane, dicumyl peroxide, 2, 5- dimethyl-2, 5- di- t-butyl peroxy Organic peroxides, such as hexane, are mentioned. In addition, you may use together 2 or more types of crosslinking agents independently. Moreover, as for the usage-amount of a crosslinking agent, 0.05-1.0 weight part is preferable normally with respect to 100 weight part of polyolefin resin particles (micropellets).

As a method of adding a crosslinking agent, for example, a method of directly adding a crosslinking agent to a polyolefin resin, a method of dissolving a crosslinking agent in a solvent, a plasticizer or a styrene monomer, and then adding it, a method of dispersing the crosslinking agent in water and then adding the crosslinking agent Can be mentioned. Among these, the method of melt | dissolving and adding a crosslinking agent to a styrene-type monomer is preferable.

(2) UV absorbers

It does not specifically limit as a ultraviolet absorber, Any well-known ultraviolet absorber can be used. Specifically 2- (2H-benzotriazol-2-yl) -p-cresol, 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) Phenol, 2- [5-chloro- (2H) -benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol, 2,4-di-tert-butyl-6- (5- Benzotriazoles such as chlorobenzotriazol-2-yl) phenol, benzophenones such as octabenzone, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- And ultraviolet absorbers such as triazine and malonic ester such as [(hexyl) oxy] phenol. Among these, benzotriazole type and benzophenone series ultraviolet absorbers are preferable.

UV absorbers are present in the impregnation system at the time of impregnating the blowing agent. The inventors believe that the ultraviolet absorber is coated on the surface layer of the resin particles and penetrates inside by contacting the resin particles with impregnation with the blowing agent. It is preferable that the usage-amount is 0.01-0.5 weight part with respect to 100 weight part of resin particles. When less than 0.01 weight part, the quantity of the ultraviolet absorber contained in the foamable resin particle obtained may become small, and as a result, desired ultraviolet shielding property may not be obtained. In the case of more than 0.5 parts by weight, considering the thickness of the foamed molded article that is usually used, even if it is added more, the effect is only obtained to an equivalent degree, the handling at the time of production is inconvenient, and the impact resistance decreases. More preferable usage-amount is 0.02-0.4 weight part.

(3) blowing agent

As the blowing agent, various known volatile blowing agents can be used. Specific examples thereof include hexane, normal pentane, isopentane, neopentane, industrial pentane, petroleum ether, normal butane, isobutane, propane, cyclohexane and cyclopentane. In particular, it is preferable to use butane and pentane.

Moreover, you may use foaming adjuvant. Examples of the foaming aid include plasticizers (high boiling point solvents) such as solvents such as cyclohexane and d-limonene, diisobutyl adipate, glycerin, diacetylated monolaurate, and palm oil. Moreover, as an addition amount of foaming adjuvant, 0.5-10 weight part is preferable with respect to 100 weight part of resin particles.

Impregnation of a blowing agent can be performed for 0.5 to 6 hours by the method well-known by itself at the temperature of 30-140 degreeC under pressure or normal pressure, for example. For example, a rotary mixer such as V-type, C-type, or DC-type is used to flow resin particles in a sealed internal pressure vessel to introduce a blowing agent to impregnate the resin particles in a sealed pressure vessel with a stirrer. The method of immersing and impregnating into a foaming agent, the method of injecting and impregnating a foaming agent into the container of the closed system after manufacture of resin particle by superposition | polymerization, etc. are mentioned.

It is preferable that content of the foaming agent in foamable resin particle is 7.5-11 weight part with respect to 100 weight part of resin particles. When content of a foaming agent is less than 7.5 weight part, the foamability of foamable resin particle may fall. When foamability falls, it becomes difficult to obtain low volume density prefoamed particles with high volume drainage, and the foamed molded article obtained by molding the prefoamed particles in a mold has a low fusion rate and a decrease in crack resistance. have. On the other hand, when it exceeds 11 weight part, the prefoamed particle | grains of the low volume density of 65 times or more of volume multiple times can be obtained. However, the bubble size in the pre-expanded particles tends to be excessive, and there is a case where a decrease in formability and a decrease in strength characteristics such as compression and warping of the resulting foamed molded article occur. More preferable content of the blowing agent is in the range of 8 to 10.5 parts by weight.

(4) Average particle diameter of the expandable resin particles

It is preferable that the average particle diameter of foamable resin particle is 800-2400 micrometers. The expandable resin particles having an average particle diameter of less than 800 µm have a poor yield when the particles are obtained, and as a result, the cost may be high. Moreover, the retention property of a foaming agent falls and there exists a tendency for bead life to shorten. When it exceeds 2400 micrometers, when shape | molding a foamed molded object of a complicated shape, there exists a tendency for the filling property to a metal mold | die to worsen. Preferable average particle diameter is 1200-2000 micrometers.

(Preliminary expanded particles)

Next, prefoamed particles can be obtained by prefoaming the expandable resin particles in a volume multiple of 5 to 60 times. Specifically, the pre-expanded particles can be obtained by heating the expandable resin particles impregnated with the blowing agent, if necessary, by preliminarily foaming them using a heating medium such as water vapor to a predetermined bulk density.

The prefoamed particles have a volume multiple of 5 to 60 times (volume density of 0.016 to 0.2 g / cm 3). Preferred volume drainage is 10 to 55 times. When the volume drainage is larger than 60 times, the independent bubble ratio of the pre-expanded particles may decrease, and the strength of the foamed molded article obtained by foaming the pre-expanded particles may decrease. On the other hand, when less than 5 times, the weight of the foamed molded object obtained by foaming prefoamed particle may increase.

(Foamed molded body)

The foamed molded article of the present invention is obtained from expandable resin particles containing an ultraviolet absorbent. In addition, the foamed molded article has a light transmittance of 365% of the wavelength of 3% or less on a sample cut to a thickness of 5 mm from the skin. In short, this foamed molded article has a high ultraviolet shielding property in an area of 5 mm thickness from the outer skin. It is preferable that the transmittance | permeability is 2% or less.

A foamed molded article can be obtained by molding the prefoamed particles in a mold. Specifically, the foamed molded article having a desired shape can be obtained by filling the pre-expanded particles into a mold of the molding machine, heating and secondary foaming, and fusion-integrating the pre-expanded particles. As said molding machine, EPS molding machine etc. which are used when manufacturing a foamed molded object from polystyrene resin prefoamed particle | grains can be used.

The obtained foamed molded article can be used for conveying containers such as cushioning materials (cushion materials) such as electric products, electronic parts, toner cartridges, various industrial materials, foods and the like. The foamed molded article is derived from the expandable resin particles in which the ultraviolet absorber is dispersed not only on the surface but also inside. For this reason, a lot of ultraviolet rays in transmitted light can be blocked at the surface of the foamed molded article and can be efficiently blocked by scattering a cell containing an ultraviolet absorber in several layers inside.

For example, when the transmittance | permeability with respect to the light of 350 nm, 500 nm, and 800 nm wavelengths about what sliced the skin part of foamed molded object about 1 mm is measured, in this invention, the transmittance | permeability in 350 nm / 500 nm A foamed molded article having a relationship in which (ratio A) is 1/2 or less and / or transmittance at 350 nm / transmittance (ratio B) at 800 nm is 1/3 or less can be obtained. The ratio A means that the lower the value, the harder the light of 350 nm wavelength to transmit than the light of 500 nm wavelength. Similarly, the ratio B means that the lower the value, the harder the light of 350 nm wavelength to transmit than the light of 800 nm wavelength. That is, the lower the ratios A and B, the higher the effect of selectively shielding ultraviolet rays.

Moreover, it is preferable that ratio A is the range of 0.4-0, and it is preferable that ratio B is the range of 0.3-0. By having a transmittance within these ranges, a foamed molded article having a high effect of selectively shielding ultraviolet rays can be obtained.

The shape of the foamed molded article is not particularly limited and can be appropriately set according to the shape of the product to be transported and / or stored. The foamed molded article of the present invention can not only efficiently block ultraviolet rays but also have excellent impact resistance, so that it can withstand long-distance transportation and long-term storage.

Example

Hereinafter, although an Example is given and it demonstrates further, this invention is not limited by these Examples.

<Foaming agent content of foamable resin particle>

5-20 mg of expandable resin particles are precisely weighed to obtain a measurement sample. The measurement sample is set in a pyrolysis furnace (manufactured by Shimadzu Corporation: PYR-1A) maintained at 180 to 200 ° C., and the measurement sample is sealed and then heated for 120 seconds to release the foaming agent component. The released foaming agent component is subjected to gas chromatography (manufactured by Shimadzu Corporation: GC-14B, detector: FID) to obtain a chart of the foaming agent component under the following conditions. The foaming agent content (weight%) in foamable resin particle is computed from the chart obtained based on the analytical curve of the foaming agent component previously measured.

Measurement conditions of gas chromatography

Column: "Shimalite '60/80' NAW" made by Nobukazu Corporation (φ 3mm * 3m)

Column temperature: 70 degrees Celsius

Detector temperature: 110 degrees Celsius

Inlet temperature: 110 degrees Celsius

Carrier gas: Nitrogen

Carrier gas flow rate: 60 ml / m

<Preliminary foaming condition>

500-2000 g of expandable resin particles were put into an atmospheric preliminary preliminary preheater (50 L in volume), and air was also supplied while introducing steam at a setting of about 0.02 MPa while stirring to provide a predetermined bulk density (volume) for about 2 to 3 minutes. Foam).

<Volume drainage of prefoamed particle>

The weight (a) of about 5 g of pre-expanded particles is weighed to the second position or less. Next, the preliminary expanded particles weighed into a 500 cm 3 mesyl cylinder having a minimum memory unit of 5 cm 3 are placed. A circular resin plate that is slightly smaller than the diameter of the measuring cylinder. A rod-shaped resin plate having a width of about 1.5 cm and a length of about 30 cm is erected at the center thereof, and the volume of the pre-expanded particles is placed on a fixed pressure port. ). Next, the volume multiple of prefoamed particle | grains is calculated | required by Formula (b) / (a).

<Drainage of foam molding>

The weight (a) and the volume (b) of the test piece (Example 75x300x35 mm) cut out from the foamed molded product (after molding and dried at 40 ° C for 20 hours or more) are measured to be at least three significant figures each. Next, the drainage of the foamed molded product is obtained by the formula (b) / (a).

<Transmittance of Foamed Molded Product>

(1) Method A

The foamed molded product is cut (sliced) to 50 x 50 x 5 mm (within ± 1 mm) with respect to the skin part to obtain a sample. As shown in FIG. 7, the light-receiving part 3 of the UV light 1 (HLR100T-2 by SEN_LIGHTS_CORP Co., Ltd., lamp: HL100) is a spectroradiometer 2 (portable spectroradiometer (MS-720 by Eco-Corporation Co., Ltd.)). UV light (1) and spectroradiometer (3) are provided so as to be directly above the) and 90 ± 5 mm from the tip of the UV light (1) to the light receiving portion (3). In the figure, 4 means a light source, 5 means a lamp cover.

First, the raw light emission degree with respect to the light of 365 nm wavelength is measured by the spectroradiometer 1. Thereafter, the sample is placed in the light receiving unit 3 and the transmission radiation to light of 365 nm wavelength is measured. The transmittance | permeability of each sample is calculated | required by substituting the obtained raw light emissivity and the transmittance emissivity of a sample as follows. The transmittance in this specification means the average value of the values measured three times for one sample.

Permeability (%) = transmittance of the sample (365 nm) ÷ raw light emission (365 nm) × 100

If the average value of the transmittance | permeability obtained by the said calculation formula is 3.0% or less, it judges that there exists favorable ultraviolet rays blocking property.

(2) Method B

The foamed molded product is cut and sliced to 40 × 40 × about 1 mm (thickness) with respect to the skin part. The sliced sample is measured using an ultraviolet visible spectrophotometer (UV-2450PC manufactured by Shimadzu Corporation). Three or more points | pieces are measured, changing the measurement location attached to one sample. Measurement conditions are made into the measurement wavelength range 800-200 nm, the slit width 2.0 nm, and the visible light ultraviolet light source switching wavelength 360 nm, and use a halogen lamp and a deuterium lamp as a light source.

From the obtained measurement results, the transmittance of 350 nm (rate A) for the transmittance of 500 nm and the transmittance of 350 nm (rate B) for the transmittance of 800 nm are respectively calculated as shown in the following equations 1 and 2 for each measurement point. do. Next, the average value of the ratio A and the ratio B of three or more measuring points is calculated | required.

When the ratio A is 1/2 or less and / or the ratio B is 1/3 or less, it is judged that there is good ultraviolet ray blocking property. In addition, this judgment is performed about the case where the transmittance | permeability of 500 nm and 800 nm is 1.0% or less.

(Transmission at 350 nm)% / (Transmission at 500 nm)% = 1/2 or less

(Transmission at 350 nm)% / (Transmission at 800 nm)% = 1/3 or less

<Ultraviolet absorber detected amount of foamed molded article>

The ultraviolet absorber is extracted in acetonitrile liquid from a sample using a high speed solvent extraction device (manufactured by Dionex). The amount of ultraviolet absorber in the obtained extract was measured by ultrafast liquid chromatography. From the obtained value, the ultraviolet absorber detection amount in a foam molding is computed by the following formula.

Ultraviolet absorber detection amount (weight%) of foam molding

= UV absorber concentration in the extract (μg / ml) x 50 (ml) / 0.2 (g) / 10000

In addition, extraction conditions and measurement conditions are as follows.

(i) extraction conditions

Measuring device: High-speed solvent extraction device ASE-350 (product made in Dionex)

Extraction temperature: 100 degrees Celsius

Extraction solvent: Acetonitrile / extraction cell = 10 ml

Extraction pressure: 10.5 MPa

Temperature rise time: Five minutes / political time: 15 minutes

Rinse amount: 25%

Purge time: 70 seconds / 3 times (the number of cycles)

Sample preparation method for extraction: 0.2g of a sample is obtained by cutting by a single cutter of width 2mm (length about 2.5 cm, height about 5-15 cm) with a small cutter so that a fixed value may be 0.2 g.

(ii) measurement conditions

Measuring apparatus: Super high-speed liquid chromatograph LaChromUltra made by Hitachi High Technologies Corporation

Column: LaChromUltra C18 2µm (2.0mmI.D. * 50mmL)

Measurement conditions: Column temperature (40 ° C), mobile phase (A = 0.05% TFA 'B = acetonitrile), mobile phase flow rate (0.6 ml / min), mobile phase conditions (0 → 2 minutes = Bconc. 50%, 2 → 4 minutes) Bconc 50% → 100%, 4 → 10 minutes = Bconc.100%), pump temperature (room temperature), measurement time (10 minutes), detection (UV = 225 nm), injection amount (2 μL)

Measurement extract preparation method: 50 ml of extracts with acetonitrile are applied. The extracted extract was filtered through a non-aqueous chromatographic disc having a diameter of 0.20 mu m to obtain an extract for measurement.

<Falling impact strength of foamed molded article>

The test piece of 215 mm (length) x 40 mm (width) x 20 mm (thickness) cut out from the foamed molded object of predetermined | prescribed multiple based on JISKK7211 is mounted on the space | interval 150 mm between points. By dropping 321 g of steel balls onto the test piece, the falling ball impact strength, that is, the 50% breaking height, is calculated by the following equation. In addition, the test piece shall have no skin on all six surfaces.

H50 = Hi + d [Σ (i? Ni) /N±0.5]

H50: 50% breaking height (cm)

Hi: Test height (cm) when height level (i) is 0, The height by which a test piece is anticipated to be destroyed.

d: Height spacing (cm) when raising and lowering test height

i: The height level which makes 0 when Hi and increases and decreases one by one

(i =… -3, -2, -1, 0, 1, 2, 3…)

ni: Number of specimens destroyed (or not destroyed) at each level

N: Total number of specimens that are destroyed (or not destroyed) (N = Σni) (Any number of data is used. Either may be used for the same number.)

± 0.5: Negative (-) when using destroyed data, plus (+) when using undamaged data.

Example  One

(Production of Resin Particles)

0.3 parts by weight of calcium silicate and stearic acid in 100 parts by weight of ethylene-vinyl acetate copolymer resin particles (LV-211 manufactured by Nippon Polyethylene, 0.3 g / 10 minutes of melt flow rate (MI), and 6.2% by weight of vinyl acetate) 0.1 weight part of calcium was added, and it knead | mixed uniformly in the extruder. The kneaded material was granulated pellets by the underwater cut method (the ethylene-vinyl acetate copolymer resin particles were adjusted to 80 mg per 100 grains).

40 parts by weight of the pellet, 120 parts by weight of pure water, 0.45 parts by weight of magnesium pyrolate, and 0.02 parts by weight of sodium dodecylbenzene sulfonic acid were added to a pressure-resistant container with an internal volume of 100 liters of stirrer to obtain a mixture. The mixture was stirred to suspend the pellet in pure water.

Next, the liquid mixture which melt | dissolved 0.03 weight part of dicumyl peroxides in 20 weight part styrene monomer as a radical polymerization initiator was dripped at this suspension over 30 minutes. After dripping was maintained for 30 minutes, the temperature of the reaction system was raised to 135 ° C, held for 2 hours, and then cooled to room temperature.

Next, after adding 0.16 weight part of dodecylbenzene sulfonic-acid soda to this suspension, the temperature of the reaction system was heated up at 90 degreeC. 0.3 part by weight of benzoyl peroxide, 0.02 part by weight of t-butyl peroxybenzoate and 0.8 part by weight of dicumyl peroxide were dissolved in 40 parts by weight of a styrene monomer to obtain a mixed solution. This mixed solution was added dropwise to the reaction system after the temperature increase over 4 hours to polymerize while absorbing the styrene monomer into the pellets. Thereafter, the reaction system was maintained at 90 ° C for 3 hours, then heated up to 135 ° C, and maintained at that temperature for 3 hours to complete polymerization. After the said polymerization was completed, it cooled to room temperature and obtained the composite resin particle.

(Impregnation and prefoaming of foaming agent and ultraviolet absorbent)

100 parts by weight of polyethylene-modified polystyrene-based resin particles in a V-type blender that can be sealed at an internal pressure of 50 liters inside, and 2- (2H-benzotriazol-2-yl) -p-cresol (chiba? Specialty? Chemical) as an ultraviolet absorber. 0.10 part by weight of TINUVIN® P) manufactured by Suzu Corporation, 0.5 part by weight of diisobutyl adipate, and 2.0 parts by weight of an aliphatic quaternary ammonium salt (Cachiogen ES-OW manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) were added, and 14 parts by weight of butane was pressurized. . And after hold | maintaining the inside of group at 60 degreeC for 2 hours, it cooled and taken out foamable resin particle. Content of the foaming agent in the obtained foamable resin particle was 9.0 weight part.

The foamed resin particles taken out were immediately prefoamed at a volume multiple of 30 times with a batch preliminary prefoam to be prefoamed particles, and then stored in a constant temperature room at a temperature of 23 ° C.

(Foaming molding)

In-mold foam molding of the obtained prefoamed particle | grain was performed. The prefoamed particle | grains were introduce | transduced in the metal mold | die of 300 mm (width) x 400 mm (length) x 30 mm (thickness), water vapor of 0.7 kgf / cm <2> was introduce | transduced for 30 second, and it heated. After heating, cooling was carried out until the foaming pressure of the foamed molded article was lowered to 0.05 kgf / cm 2 or less, and the foamed molded article with a multiple of 30 times was taken out.

The foamed molded product taken out was left to stand for 6 hours or more in 35 degreeC atmosphere. The transmittance | permeability of the skin part of the obtained foamed molded object is measured, and a result is shown in FIG. Table 1 shows the transmittances (method B), the ratios A and B, the falling ball impact value, and the ultraviolet absorber detection amount at 350 nm, 500 nm, and 800 nm calculated from the transmittance and the measurement result by the method A.

Example  2

It carried out similarly to Example 1 except having used octabenzone (CHIMASSORB 81 by Chiba-Specialty Chemicals) as a ultraviolet absorber. Content of the foaming agent in the obtained foamable resin particle was 8.9 weight part. Moreover, the transmittance | permeability of the skin part of the obtained foamed molded object is measured, and a result is shown in FIG. Table 1 shows the transmittances (method B), the ratios A and B, the falling ball impact value, and the ultraviolet absorber detection amount at 350 nm, 500 nm, and 800 nm calculated from the transmittance and the measurement result by the method A.

Example  3

It carried out similarly to Example 1 except having used 2- (2H-benzotriazol-2-yl) -4,6-di-tert-pentylphenol (TINUVIN 328 by Chiba Specialty Chemicals) as a ultraviolet absorber. . Content of the foaming agent in the obtained foamable resin particle was 8.9 weight part. Moreover, the transmittance | permeability of the skin part of the obtained foamed molded object is measured, and a result is shown in FIG. Table 1 shows the transmittances (method B), the ratios A and B, the falling ball impact value, and the ultraviolet absorber detection amount at 350 nm, 500 nm, and 800 nm calculated from the transmittance and the measurement result by the method A.

Example  4

It carried out similarly to Example 1 except having used 2- (2H- benzotriazol-2-yl) -6-dodecyl-4-methylphenol (TINUVIN 571 by Chiba Specialty Chemicals) as a ultraviolet absorber. Content of the foaming agent in the obtained foamable resin particle was 9.0 weight part. Moreover, the transmittance | permeability of the skin part of the obtained foamed molded object is measured, and a result is shown in FIG. Table 1 shows the transmittances (method B), the ratios A and B, the falling ball impact value, and the ultraviolet absorber detection amount at 350 nm, 500 nm, and 800 nm calculated from the transmittance and the measurement result by the method A.

Example  5

Impregnation of the foaming agent and the ultraviolet absorber was carried out in the same manner as in Example 1 except that the impregnation of the foaming agent and the ultraviolet absorbent was carried out as follows. Content of the foaming agent in the obtained foamable resin particle was 8.5 weight part. Moreover, the transmittance | permeability of the skin part of the obtained foamed molded object was measured. Table 1 shows the transmittance (method B), the ratios A and B, the falling ball impact value, and the ultraviolet absorbent detection amount at 350 nm, 500 nm, and 800 nm calculated from the transmittance by the method A and the measurement results.

(Wet impregnation)

100 parts by weight of a composite resin particle, 0.04 part by weight of soda dodecylbenzene sulfonic acid, alkyl monoethanol amine (Namine L-201 manufactured by Sunyou Co., Ltd.) in 100 parts by weight of water in a pressure-resistant container with a stirrer capable of being sealed at an internal pressure of 5 liters 0.3 part by weight and 0.10 part by weight of 2- (2H-benzotriazol-2-yl) -p-cresol (TINUVIN P) as a ultraviolet absorber were added, stirred and suspended.

Thereafter, 14 parts by weight of butane was pressed into the container. Then, the temperature of suspension was heated up to 70 degreeC and hold | maintained for 3 hours. After cooling, the obtained expandable resin particles were taken out.

Comparative example  One

It carried out similarly to Example 1 except not having added the ultraviolet absorber. Content of the foaming agent in the obtained foamable resin particle was 8.9 weight part. Moreover, the transmittance | permeability of the skin part of the obtained foamed molded object is measured, and a result is shown in FIG. Table 1 shows the transmittances (method B), the ratios A and B, and the falling ball impact value at 350 nm, 500 nm, and 800 nm calculated from the transmittance by the method A and the measurement results.

Comparative example  2

It carried out similarly to the comparative example 1 except having impregnated with a foaming agent in the wet manner like Example 5. Content of the foaming agent in the obtained foamable resin particle was 8.6 weight part. Moreover, the transmittance | permeability of the skin part of the obtained foamed molded object was measured. Table 1 shows the transmittances (method B), the ratios A and B and the falling ball impact value at 350 nm, 500 nm and 800 nm calculated from the transmittance by the method A and the measurement results.

Example  6

It carried out similarly to Example 1 except having made the addition amount of a ultraviolet absorber into 0.05 weight part. Content of the foaming agent in the obtained foamable resin particle was 8.8 weight part. Moreover, the transmittance | permeability of the skin part of the obtained foamed molded object was measured. Table 2 shows the transmittance (method B), the ratios A and B, the falling ball impact value, and the ultraviolet absorbent detection amount at 350 nm, 500 nm and 800 nm calculated from the transmittance and the measurement result by the method A.

Example  7

It carried out similarly to Example 1 except having made the addition amount of a ultraviolet absorber into 0.05 weight part. Content of the foaming agent in the obtained foamable resin particle was 9.2 weight part. Moreover, the transmittance | permeability of the skin part of the obtained foamed molded object is measured, and a result is shown in FIG. Table 2 shows the transmittances (method B), the ratios A and B, the falling ball impact value, and the ultraviolet absorbent detection amount at 350 nm, 500 nm, and 800 nm calculated from the transmittance by the method A and the measurement results.

Example  8

It carried out similarly to Example 1 except having made the addition amount of a ultraviolet absorber into 0.02 weight part. Content of the foaming agent in the obtained foamable resin particle was 9.0 weight part. Moreover, the transmittance | permeability of the skin part of the obtained foamed molded object was measured. Table 2 shows the transmittance (method B), the ratios A and B, the falling ball impact value, and the ultraviolet absorbent detection amount at 350 nm, 500 nm and 800 nm calculated from the transmittance and the measurement result by the method A.

Example  9

It carried out similarly to Example 1 except having made the addition amount of a ultraviolet absorber into 0.005 weight part. Content of the foaming agent in the obtained foamable resin particle was 8.9 weight part. Moreover, the transmittance | permeability of the skin part of the obtained foamed molded object was measured. Table 2 shows the transmittance (method B), the ratios A and B, the falling ball impact value, and the ultraviolet absorbent detection amount at 350 nm, 500 nm and 800 nm calculated from the transmittance and the measurement result by the method A.

Example  10

It carried out similarly to Example 5 except having made the addition amount of a ultraviolet absorber into 0.02 weight part. Content of the foaming agent in the obtained foamable resin particle was 8.9 weight part. Moreover, the transmittance | permeability of the skin part of the obtained foamed molded object was measured. Table 2 shows the transmittance (method B), the ratios A and B, the falling ball impact value, and the ultraviolet absorbent detection amount at 350 nm, 500 nm and 800 nm calculated from the transmittance and the measurement result by the method A.

Example  11

It carried out similarly to Example 1 except having made the volume drainage of preexpanded particle | grains, and the drainage of foamed molded object 15 times. Content of the foaming agent in the obtained foamable resin particle was 8.8 weight part. Table 3 shows the transmittance and falling impact values by Method A.

Example  12

(Production of Resin Particles)

LLDPE synthesized using a metallocene catalyst as a straight chain low density polyethylene resin not crosslinked (trade name "NF-444A" manufactured by Japan Polyethylene Co., Ltd., melt index (MI) = 2.0 g / 10 min, density: 0.912 g / cm 3) Was used. This resin was thrown into the extruder and melt-kneaded. The kneaded material was made into granulated pellets by the underwater cut method (approximately spherical, polyethylene resin particles were adjusted to about 60 mg per 100 grains).

0.8 parts by weight of magnesium pyrolate and 0.02 parts by weight of soda dodecyl benzene sulfonic acid were dispersed in 100 parts by weight of water in a pressure-resistant container with a 100 liter stirrer to obtain a dispersion medium. 100 weight part of said polyethylene-type resin particle was disperse | distributed to the dispersion medium, and suspension was obtained.

Next, 0.2 weight part of dicumyl peroxide was previously melt | dissolved in 100 weight part of styrene monomers as a polymerization initiator, and the 1st styrene monomer solution was obtained. The temperature of the suspension was adjusted to 60 ° C. and the first styrene monomer solution was added to the suspension quantitatively over 30 minutes. Then, it stirred at 60 degreeC for 1 hour, and impregnated the styrene monomer in the polyethylene-type resin particle. Next, the temperature of the dispersion was raised to 130 ° C. and 130 ° C. was maintained for 2 hours to polymerize the styrene monomer in the polyethylene resin particles.

Subsequently, 0.35 weight part of dicumyl peroxide as a polymerization initiator was melt | dissolved in 300 weight part of styrene monomers, and the 2nd styrene monomer solution was obtained. The 2nd styrene monomer solution was continuously dripped at the ratio of 60 weight part per hour over 5 hours to the previous polymerization system. The styrene monomer in the second styrene monomer solution was polymerized while being impregnated in the polyethylene resin particles. After the said polymerization, it cooled to normal temperature and obtained composite resin particle.

(Impregnation and prefoaming of foaming agent and ultraviolet absorbent)

Foamed resin particles were obtained in the same manner as in Example 1 except that the amount of diisobutyl adipate was 0.9 parts by weight, the amount of butane was 18 parts by weight, and no aliphatic quaternary ammonium salt was used. Content of the foaming agent in the obtained foamable resin particle was 9.1 weight part. By pre-expanding the expandable resin particles in the same manner as in Example 1, pre-expanded particles having a volume multiple of 50 times were obtained, and then stored in a constant temperature room at a temperature of 23 ° C.

(Foaming molding)

In-mold foam molding was performed in the same manner as in Example 1 to obtain a foam molded product having a multiple of 50 times. Table 3 shows the transmittance and falling impact values by Method A.

Example  13

It carried out similarly to Example 12 except having made the addition amount of a ultraviolet absorber into 0.02 weight part. Content of the foaming agent in the obtained foamable resin particle was 9.1 weight part. Table 3 shows the transmittance and falling impact values by Method A.

Example  14

(Production of Resin Particles)

40000 parts by weight of water, 100 parts by weight of tricalcium phosphate and 2.0 parts by weight of calcium dodecylbenzene sulfonate were supplied to a polymerization vessel with a stirrer of 100 liters content to obtain a dispersion. Next, 40000 parts by weight of styrene monomer, 96.0 parts by weight of benzoyl peroxide and 28.0 parts by weight of t-butyl peroxybenzoate were added to the dispersion under stirring. It heated up at 90 degreeC after addition, and superposed | polymerized the styrene-type monomer. And it maintained at this temperature for 6 hours, and heated up further at 125 degreeC. After raising the temperature, the polystyrene resin particles (A) were obtained by cooling to room temperature after 2 hours.

By sorting the polystyrene resin particles (A) into a sieve, polystyrene resin particles (B) having a particle diameter of 0.5 to 0.71 mm were obtained as seed particles.

Next, 2000 parts by weight of water, 500 parts by weight of polystyrene-based resin particles (B), 6.0 parts by weight of magnesium pyrolate, and 0.3 parts by weight of calcium dodecylbenzene sulfonate were fed into a polymerization vessel with a stirrer of 5 vol. The feed was heated to 70 ° C. while stirring.

Next, 4.5 parts by weight of benzoyl peroxide and 1.1 parts by weight of t-butyl peroxybenzoate were dissolved in 200 parts by weight of styrene monomer to obtain a solution. This solution was supplied to the said 5 liter polymerization vessel. After 30 minutes had elapsed, the temperature was raised to 100 ° C., and 1300 parts by weight of the styrene monomer was fed into the 5 liter polymerization vessel by a constant amount by a pump over 2 hours. After supplying, it heated up at 120 degreeC and after heating up, it cooled to room temperature after 2 hours, and obtained polystyrene resin particle (C).

(Impregnation of foaming agent and ultraviolet absorbent)

Subsequently, 2200 parts by weight of water, 1800 parts by weight of polystyrene-based resin particles (C), 6.0 parts by weight of magnesium pyrolate, 0.4 parts by weight of calcium dodecylbenzene sulfonate, and a UV absorber were added to a polymerization vessel with a stirrer having a different content of 5 liters. 1.8 parts by weight of (2H-benzotriazol-2-yl) -p-cresol (TINUVIN P) (0.1 parts by weight relative to the polystyrene resin) was fed and heated to 70 ° C while stirring. Next, 18.0 parts by weight of cyclohexane as a foaming aid and 12.6 parts by weight of diisobutyl adipate as a plasticizer were placed in a polymerization vessel and sealed, and the temperature was raised to 100 ° C.

Next, 100 parts by weight of n-butane was pressed into a polymerization vessel containing polystyrene-based resin particles (C) as a blowing agent, and held for 3 hours. Then, after cooling to 30 degrees C or less, foamable resin particle was taken out from the inside of a polymerization container. The foamed resin particles taken out were dried and left for 5 days in a constant temperature chamber at 13 ° C.

(Preliminary foaming and foam molding)

It carried out similarly to Example 1 except using the said foamable resin particle. Content of the foaming agent in the obtained foamable resin particle was 8.5 weight part. Table 3 shows the transmittance and falling impact values by Method A.

In Tables 1-3, (circle), (triangle | delta), and x in an evaluation result are based on the following criteria. That is, it is preferable that the foamed molded product has both ultraviolet ray shielding properties and falling ball impact values. Therefore, in this specification, it is prescribed | regulated that it is preferable that ultraviolet-ray shielding property satisfy | fills the following conditions (I), and a fall ball impact value satisfy | fills the following conditions (II).

Condition (I): The transmittance | permeability by method A is 3.0% or less

Condition (II): Falling impact value of 35 cm or more

(Circle), (triangle | delta), and (x) evaluate an Example and a comparative example as follows from a viewpoint of conditions (I) and (II).

○: Both conditions (I) and (II) are satisfied.

(Triangle | delta): Only one of condition (I) and (II) is satisfied.

X: The condition (I) is not satisfied.

In Table 3, EVA means ethylene-vinyl acetate copolymer, PS means polystyrene, and mLLDPE means non-crosslinked linear low density polyethylene resin by metallocene catalyst, respectively.

It is understood from Examples 1 to 14 and Comparative Examples 1 to 2 that the expandable resin particles contain an ultraviolet absorber, thereby improving the shielding of the ultraviolet rays of the foamed molded article obtained by using it as a raw material. The improvement of the shielding of an ultraviolet-ray is also evident from FIGS. That is, in the drawing, Examples 1 to 5 are clearly reduced than Comparative Example 1 with respect to light having a wavelength of 400 to 300 nm, which is the wavelength region of ultraviolet rays. Thus, it is shown that the shielding of ultraviolet rays is improved by including an ultraviolet absorber. have.

Moreover, even if it changes the ultraviolet absorber by Examples 1-4, it turns out that the shielding property of the ultraviolet-ray of the foamed molded object obtained using foamable resin particle as a raw material is improving. In addition, the conventional ultraviolet absorber was disperse | distributed in resin particle by kneading with resin which requires comparatively high temperature. However, in Examples 1-5, the ultraviolet absorber is impregnated inside resin by the impregnation process of the foaming agent performed at 50-70 degreeC low temperature. For this reason, it turns out that the foamed molded object which can block an ultraviolet-ray can be obtained simply and easily.

In addition, it is understood that the foamed molded article obtained in Examples 1 to 14 has a falling ball impact strength that is sufficiently applicable to the transportation and storage container of an electric product.

Moreover, from Example 1 and 5, even if a ultraviolet absorber is provided in either dry or wet, it turns out that favorable ultraviolet-ray shielding property is obtained.

In addition, it can be seen from Examples 1 and 6 to 9 that the shielding of ultraviolet rays is improved by increasing the amount of the ultraviolet absorber.

Moreover, from Example 1, 12, and 14, it turns out that the favorable ultraviolet-ray shielding property is obtained even if it changes a resin species. Moreover, it turns out that the fall ball impact value is better in which the polyolefin component is contained.

In addition, it can be seen from Examples 1 and 11 that good shielding of ultraviolet rays is obtained even if the expansion ratio is changed.

Next, a graph showing the emissivity for each wavelength of UV light used in the method A is shown in Fig. 8 (a), and a graph showing the emissivity for each wavelength of the foamed molded article of Example 1 and Comparative Example 1 is shown in Fig. 8 (b). Shown in In FIG.8 (b), the dotted line shows Example 1 and the solid line shows Comparative Example 1. FIG. It can be seen from FIG. 8B that the foamed molded article of Example 1 can meaningfully shield light having a wavelength around 365 nm.

1 UV light
2 spectroradiometer
3 light receiver
4 light source
5 lamp cover

Claims (7)

The manufacturing method of foamable resin particle which obtains foamable resin particle which has ultraviolet-ray shielding property by making the resin particle which can become foamable resin particle impregnate a foaming agent, and making a contact with said resin particle an ultraviolet absorber. The method according to claim 1,
The said ultraviolet absorber is a benzotriazole type or a benzophenone type ultraviolet absorber, and 0.01-0.5 weight part of manufacturing methods of foamable resin particle are used with respect to 100 weight part of said resin particles. The method according to claim 1,
The said resin particle is a manufacturing method of foamable resin particle which is a resin particle containing polyolefin resin and polystyrene resin. The method according to claim 1,
The said resin particle is a manufacturing method of foamable resin particle which is a resin particle containing 100 weight part of polyolefin resin and 120-560 weight part of polystyrene resins. Preliminary expanded particles obtained by prefoaming the expandable resin particles obtained by the method according to claim 1 in a volume multiple of 5 to 60 times. It is a foamed molded article obtained from expandable resin particles containing a ultraviolet absorber,
The foamed molded article has a transmittance of light having a wavelength of 365 nm of 3% or less in a sample cut to a thickness of 5 mm from the skin. The method of claim 6,
The said resin contains polyolefin resin and polystyrene resin, The said ultraviolet absorber is a benzotriazole type or a benzophenone type ultraviolet absorber, 0.01-0.5 weight part is used with respect to 100 weight part of said resins.

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