JP2005023252A - Reclaimed foaming styrenic resin particle, reclaimed foaming bead, and reclaimed foaming styrenic resin moulding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a preparation method of spherical reclaimed foaming styrenic resin particles from drawn pellets. <P>SOLUTION: The method of producing reclaimed foaming styrenic resin particles comprises: suspending reclaimed styrenic resin pellets of each with a cylindrical shape having the length of ≤5.0 mm, diameter of ≤3.0 mm and a size shrinkage rate along the length-wise direction of ≤50 % in an aqueous medium as nuclei, successively impregnating the styrenic pellets with a polymerization initiator and a styrenic monomer, then adding a styrenic monomer to the pellets to carry out polymerization, and impregnating the pellets with a foaming agent at a temperature ≥100 °C. The ratio of the reclaimed styrene-based resin pellets to the reclamation foaming styrenic particles is ≤70 wt.%. The spherical reclaimed styrenic resin particles are prepared by the above method. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４８】
実施例２
実施例１において、押出機の材料フィードモーター回転数を１．５ｒｐｍ、ペレタイザーの回転数を５５０ｒｐｍとした以外は、実施例１と同様な操作を行い、再生スチレン系樹脂ペレットを得た。このペレットの延伸方向の長さは、２．５〜３．０ｍｍであり、径は、０．８〜１．１ｍｍであった。また、ペレットを２００℃雰囲気下で１０分加熱後の延伸方向の寸法収縮率は３３〜３９％であった。
この再生スチレン系樹脂ペレットを用い、実施例１と同様な操作を行い、再生発泡性スチレン系樹脂粒子、及び発泡成形品を得た。
【００４９】
比較例１
実施例１において、押出機の材料フィードモーター回転数を１．２ｒｐｍ、ペレタイザーの回転数を７００ｒｐｍとした以外は、実施例１と同様な操作を行い、再生スチレン系樹脂ペレット得た。このペレットの延伸方向の長さは、２．８〜３．３ｍｍであり、径は、０．６〜０．９ｍｍであった。また、ペレットを２００℃雰囲気下で１０分加熱後の延伸方向の寸法収縮率は６５〜７２％であった。
この再生スチレン系樹脂ペレットを用い、実施例１と同様な操作を行い、再生発泡性スチレン系樹脂粒子、及び発泡成形品を得た。
【００５０】
比較例２
実施例１において、発泡剤の圧入を９０℃で行い、１０時間保持して発泡剤の含浸を行った以外は、実施例１と同様な操作を行い、再生発泡性スチレン系樹脂粒子、及び発泡成形品を得た。
【００５１】
比較例３
５リットルの耐圧撹拌容器に脱イオン水２０００ｇ、実施例１と同様の方法で作製した再生スチレン系樹脂ペレット１７６０ｇ、リン酸三カルシウム１７．６ｇ、ドデシルベンゼンスルホン酸ナトリウム０．０４ｇを仕込み、撹拌しながら７５℃に昇温した。
次いで、単量体分散容器に脱イオン水３００ｇとポリビニルアルコール０．１ｇを入れ混合し、これにｔ−ブチルパーオキサイド０．１ｇ、ベンゾイルパーオキサイド０．９ｇを溶解したスチレン単量体３００ｇを加え、ホモミキサー（特殊機化工業製）を用いて５８００ｒｐｍで１２０秒撹拌しスチレン単量体を微細（単量体油滴の平均径１０〜１００μｍ）に分散させた。このスチレン単量体分散液を容器内に添加し、６０分保温したのち、９０℃に昇温した。ついで、スチレン単量体１４０ｇを連続的に１時間かけて等速度（２．３ｇ／分）で添加した。
次いで、リン酸三カルシウム２．２ｇ、ドデシルベンゼンスルホン酸ナトリウム０．０５ｇを添加した後、１１５℃に昇温し、２時間保温した。ついで、１００℃まで冷却し、発泡剤としてブタン（ｉ／ｎ比＝４／６、重量比以下同じ）１８０ｇを２回に分けて圧入し、２時間保持した後、１２０℃に昇温し発泡剤の含浸を行った。
室温まで冷却後、発泡剤が含浸された再生発泡性スチレン系樹脂粒子を取り出し、脱水乾燥した。
次いでこの重合体粒子を目開き２．８ｍｍ及び１．２ｍｍの篩で分級し、
１５２０ｇの樹脂粒子を得た。得られた樹脂粒子に対し、ステアリン酸亜鉛１．１ｇ、次いで硬化ひまし油２．２ｇを順次加えて混合し、再生発泡性スチレン系樹脂粒子を得た。
この再生発泡性スチレン系樹脂粒子を用い、実施例１と同様な操作を行い、発泡成形品を得た。
【００５２】
比較例４
実施例１において、押出機の材料フィードモーター回転数を８．５ｒｐｍ、ペレタイザーの回転数を３５０ｒｐｍとした以外は、実施例１と同様な操作を行い、再生スチレン系樹脂ペレット得た。このペレットの延伸方向の長さは、６．５〜７．８ｍｍであり、径は、２．６〜３．４ｍｍであった。また、ペレットを２００℃雰囲気下で１０分加熱後の延伸方向の寸法収縮率は１５〜１８％であった。
この再生スチレン系樹脂ペレットを用い、実施例１と同様な操作を行い、再生発泡性スチレン系樹脂粒子、及び発泡成形品を得た。
【００５３】
【発明の効果】
本発明によれば、発泡スチレン系樹脂成形品の再利用において、延伸ペレットから、球形の再生発泡性スチレン系樹脂粒子を製造する方法を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to regenerated foamable styrene resin particles, regenerated foam beads, and regenerated foamed styrene resin molded articles obtained by regenerating foamed styrene resin molded articles.
[0002]
[Prior art]
Conventionally, foamed styrene resin molded products have been used once and then incinerated, or they are heat-shrinked and recovered and reused as polystyrene. However, the reuse ratio is insufficient and will be reused in the future. Increasing the utilization rate is a social issue.
[0003]
The technology for recovering foamed styrene resin molded products as contracted lumps has already been completed. In 1999, about 33% of the amount of foamed styrene resin molded products distributed in Japan was recovered as heat contracted lumps. It is mainly used for miscellaneous goods by injection molding and building materials by extrusion molding. Thus, at present, the recycling method of the foamed styrene resin molded product is limited, and its application is urgently expanded.
[0004]
On the other hand, from the definition of recycling, foamable styrene resin particles are foam-molded, and the styrene resin finally used as the foamed styrene-resin molded product is not used for other purposes as polystyrene. It is considered that it is preferable to reuse as expandable styrenic resin particles, but at present, styrene resin recovered from expanded styrene resin molded products is industrially regenerated as expandable styrene resin particles. There are few.
[0005]
As a method for regenerating the expandable styrene resin particles from the shrinkage of the foamed styrene resin molded product, the method of pelletizing the shrinkage with an extruder and impregnating it with a foaming agent is the most technically easy. However, in the most commonly used strand type extruder, strain remains in the stretching direction, and thus the regenerated expandable styrenic resin particles impregnated with the foaming agent contract in the stretching direction, resulting in a flat or oval shape. It becomes a shape. For this reason, when filling the expanded beads with the foamed foam into the mold, the shape is not spherical, so that the filling property is inferior, there are many defects due to insufficient filling, and the appearance of the obtained molded product is inferior. .
[0006]
As a method of regenerating expandable styrene resin particles from shrinkage of expanded styrene resin molded products, etc., pellets obtained by heating and melting a pulverized expanded styrene resin molded product in an extruder are dispersed in water. Then, a method of adding and polymerizing a styrene monomer solution containing a catalyst has been proposed. (For example, see Patent Document 1)
However, this method is effective for relatively clean molded products such as defective products that occur during molding. However, when a molded product that is actually used in the market and is contaminated with foreign matter is used as a raw material, an extruder is used. However, it is necessary to increase the diameter of the die for mass production, and the resulting pellet size increases. When the pellet size is large, the proposed method has a problem of poor filling property to the mold and appearance of the molded product because the particles are difficult to spheroidize and have a flat or oval shape.
[0007]
In addition, as a method for regenerating spherical expandable styrene resin particles from shrinkage of foamed styrene resin molded products, etc., styrene resin particles obtained by non-stretching melting and pulverizing shrinkage of foamed styrene resin molded products Has been proposed in which re-expandable styrene resin particles are produced by dispersing in an aqueous medium containing an organic dispersant and impregnated with a readily volatile foaming agent (see, for example, Patent Document 2).
However, in this method, it is necessary to make the shrinkage of the foamed styrene resin molded product into an unstretched pellet with an extruder or the like, but since an extruder that can produce an unstretched pellet is not common, there is equipment that can be produced. Therefore, the production amount is limited, and the pellet size is larger than the pellets obtained by a general strand type extruder. Therefore, it is necessary to finely pulverize to the desired size. It was disadvantageous in terms of cost.
[0008]
[Patent Document 1]
JP-A-5-98062
[Patent Document 2]
JP-A-6-87973
[0009]
[Problems to be solved by the invention]
Accordingly, the present invention provides spherical regenerated foamable styrene resin particles from regenerated styrene resin pellets (stretched pellets) obtained from a foamed styrene resin molded product using the most widely adopted strand type extruder. A method of manufacturing is provided.
[0010]
[Means for Solving the Problems]
According to the present invention, a regenerated styrene resin pellet having a columnar shape with a length of 5.0 mm or less and a diameter of 3.0 mm or less and a dimensional shrinkage of 50% or less in the length direction is used as a core, and is aqueous. Suspended in a medium, impregnated with a polymerization initiator and a styrene monomer into a regenerated styrene resin pellet, subsequently added with a styrene monomer to perform polymerization, and then foamed at an impregnation temperature of 100 ° C. or higher. Of regenerated expandable styrene resin particles impregnated with an agent, wherein the ratio of regenerated styrene resin pellets to regenerated expandable styrene resin particles is 70% by weight or less A method is provided.
[0011]
According to the present invention, there is provided regenerated expandable styrene resin particles obtained by the method for producing regenerated expandable styrene resin particles.
[0012]
According to the present invention, there is provided a regenerated styrene-based expanded bead obtained by expanding the regenerated expandable resin particles.
[0013]
According to the present invention, there is provided a regenerated expanded styrene resin molded product obtained by foam molding of the above regenerated styrene expanded beads.
[0014]
According to the present invention, a regenerative foaming property comprising a regenerated styrene resin pellet having a columnar shape having a length of 5.0 mm or less and a diameter of 3.0 mm or less and a dimensional shrinkage in the length direction of 50% or less. Nuclei for use in the production of styrenic resin particles are provided.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the method for producing the regenerated expandable styrene resin particles of the present invention and the foam molded product obtained by foam molding thereof will be described in detail.
The method for producing regenerated expandable styrene resin particles of the present invention comprises suspending regenerated styrene resin pellets as a core in an aqueous medium and impregnating the regenerated styrene resin pellets with a polymerization initiator and a styrene monomer. Then, a styrene monomer is added and polymerized, and then impregnated with a foaming agent.
[0016]
The regenerated styrene resin pellets used in the present invention can be produced by extruding a pulverized product obtained by roughly pulverizing a shrinkage or melt of a used expanded styrene resin to an appropriate size as required.
The shrinkage or melt of the used expanded styrene resin is preferably prepared by excluding the used expanded styrene resin molded product previously colored with a dye or the like. If a colored molded product is mixed, the regenerated expandable styrene resin particles and foamed molded product obtained from the colored product are colored, which is not preferable.
[0017]
In addition, used styrene resin shrinkage or melted pulverized product, fatty acid monoamides such as oleic acid amide and stearic acid amide, fatty acid bisamides such as methylene bisstearic acid amide and ethylene bisstearic acid amide, talc, etc. The inorganic substance can be mixed as a bubble regulator. In this case, the pulverized material and the air bubble adjusting agent are mixed in advance and then extruded. Although the quantity of a bubble regulator can be mix | blended suitably, it is 0.01 to 2.0 weight%, for example.
Mixing of the pulverized product and the bubble adjusting agent can be performed by a conventionally known means. For example, a blender such as a ribbon blender, a V blender, a Henschel mixer, or a ready game mixer can be used.
[0018]
Such a pulverized product is extruded using a known extruder, for example, a single-screw extruder, a twin-screw extruder or the like with a strand die attached (strand-type extruder), and a regenerated styrene type Resin pellets can be produced.
Specifically, a used expanded styrene resin shrinkage or melted pulverized product, or a mixture of this and an air conditioner is charged into an extruder and melt kneaded. The melt extruded in the form of a strand from the die at the tip of the extruder is introduced into a pelletizer while being cooled, cut to an appropriate length, and made into a substantially cylindrical regenerated styrenic resin pellet.
[0019]
The length of the regenerated styrene resin pellets in the stretching direction is preferably 5.0 mm or less, more preferably 3.0 mm or less. If the length in the stretching direction exceeds 5.0 mm, the particles are difficult to spheroidize. Moreover, since there is no demand if the regenerated foamable styrene resin particles are too small, the length of the pellet is preferably 0.3 mm or more.
[0020]
The diameter of the pellet is preferably 3.0 mm or less, more preferably 2.0 mm or less. When the diameter of the pellet exceeds 3.0 mm, the particles are difficult to spheroidize. In addition, since there is no demand if the regenerated expandable styrene resin particles are too small, the diameter of the pellet is preferably 0.3 mm or more.
The ratio of the length and diameter of the pellets is preferably 4: 1 to 1: 2, more preferably 2: 1 to 1: 1.
[0021]
The dimensional shrinkage ratio in the stretching direction after heating the pellet in a 200 ° C. atmosphere for 10 minutes is 50% or less, preferably 30% or less. When the dimensional shrinkage rate exceeds 50%, the obtained particles are difficult to spheroidize.
Note that “stretched” means forming while pulling out, for example, having a dimensional shrinkage of 10% or more.
[0022]
The length of the regenerated styrene resin pellet in the stretching direction can be controlled by adjusting the cutting speed, for example, adjusting the rotation speed of the pelletizer.
Moreover, the diameter and dimensional shrinkage ratio of the pellet can be controlled by adjusting the discharge amount and cutting speed (take-off speed) of the extruder.
[0023]
The weight average molecular weight of the obtained regenerated styrene resin pellets is preferably 100,000 to 250,000. If the weight average molecular weight is less than 100,000, sufficient strength tends not to be obtained, and if it exceeds 250,000, the particles tend to be difficult to be spheroidized. More preferably, it is 150,000-230,000.
[0024]
The recycled styrene resin pellets may be blended with the same additive as the above-mentioned used expanded styrene resin shrinkage or crushed melt.
[0025]
The regenerated styrene resin pellets produced as described above are suspended in an aqueous medium to form a suspension. Dispersion in an aqueous medium is usually performed using an apparatus equipped with a stirring blade, and there are no restrictions on the conditions.
[0026]
The regenerated styrene resin pellet is preferably dispersed together with a dispersant. The dispersant used in the present invention is generally only required to be used for suspension polymerization. For example, organic dispersants such as polyvinyl alcohol, polyvinyl pyrrolidone, and methyl cellulose, magnesium phosphate, tricalcium phosphate, etc. Examples include hardly soluble inorganic salts.
Furthermore, a surfactant can also be used. For example, sodium oleate, sodium dodecylbenzenesulfonate, other anionic surfactants commonly used in suspension polymerization, and nonionic surfactants can be used. .
Among these dispersants, it is preferable to use an organic dispersant from the viewpoint of the stability of the oil droplets of the styrene monomer.
[0027]
Next, a styrene monomer in which a polymerization initiator is dissolved in advance is added to the above suspension, and impregnated into regenerated styrene resin pellets serving as nuclei.
The styrenic monomer used in the present invention is one or more styrene derivatives such as styrene, α-methylstyrene, and vinyltoluene, or these and methacrylic acid esters such as methyl methacrylate and ethyl methacrylate. And combinations with other polymerizable monomers such as vinyl cyanide such as acrylate, acrylonitrile and methacrylonitrile, and vinyl chloride.
In addition, a crosslinking agent such as divinylbenzene or diallyl phthalate may be used.
[0028]
As the polymerization initiator used in the polymerization reaction, any polymerization initiator may be used, for example, t-butyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexyl carbonate, t-butylperoxide. One or more organic peroxides such as benzoate and azo compounds such as azobisisobutyronitrile can be used.
[0029]
The polymerization initiator may be added after being dissolved in a solvent and impregnated into regenerated styrene resin pellets. In this case, as the solvent, aromatic hydrocarbons such as ethylbenzene and toluene, aliphatic hydrocarbons such as heptane and octane, etc. are used. When these are used, usually 3% by weight based on the styrene monomer. Used in:
Although the usage-amount of a polymerization initiator changes with kinds of polymerization initiator, generally the range of 0.1 to 0.5 weight% is preferable with respect to a monomer.
[0030]
In the present invention, fatty acid monoamides such as oleic acid amide and stearic acid amide, fatty acid bisamides such as methylene bis stearic acid amide and ethylene bis stearic acid amide, etc. are dissolved in the styrenic monomer or the solvent as a bubble regulator. May be used.
[0031]
As a method of impregnating a styrene monomer into a core composed of regenerated styrene resin pellets dispersed in an aqueous medium, a method of adding a styrene monomer alone, or a styrene monomer in an aqueous medium Alternatively, there is a method of adding as a dispersion finely dispersed by adding a dispersant or the like. Moreover, you may combine these methods.
A method of adding a styrenic monomer, a dispersant, or the like to an aqueous medium to finely disperse is usually performed using an apparatus equipped with a stirring blade. The conditions are not limited, but it is preferable to use a homomixer as a method for finer dispersion. At this time, it is preferable to disperse until the oil droplet diameter of the dispersion liquid in which the styrene monomer is dispersed is equal to or smaller than the particle diameter of the core. When added to an aqueous medium in a state where the oil droplet size is larger than the core particle size, a plurality of resin particles are taken into the oil droplets of the dispersion liquid in which the styrenic monomer is dispersed, and the resin particles are adhered and plasticized. This is because crystallization and coalescence occur and excessive particles are likely to be generated.
[0032]
A styrene monomer in which a polymerization initiator is dissolved is added to the suspension and impregnated in a regenerated styrene resin pellet as a core, and then a styrene monomer is added to perform polymerization.
The addition of the styrenic monomer may be performed separately or continuously. Further, the addition rate varies depending on the capacity, shape, polymerization temperature, etc. of the polymerization apparatus and is appropriately selected. The polymerization temperature is preferably in the range of 60 to 105 ° C.
[0033]
The total molecular weight can be adjusted by adjusting the concentration of the polymerization initiator, using a chain transfer agent together, or both. As the chain transfer agent, conventionally known ones such as octyl mercaptan, dodecyl mercaptan, α-methylstyrene dimer can be used.
[0034]
Subsequently, the foaming agent is impregnated into the resin particles obtained by polymerizing the styrenic monomer in the pellets serving as nuclei during or after the polymerization.
In the impregnation with the foaming agent, the foaming agent is press-fitted into the container, and the temperature is usually raised to a temperature equal to or higher than the softening point of the regenerated styrene resin particles, and the resin particles are impregnated.
As the foaming agent, those that do not dissolve or slightly swell resin particles are preferable. Specifically, aliphatic hydrocarbons such as propane, normal butane, isobutane, normal pentane, isopentane, normal hexane, cyclohexane, cyclopentane, and the like. An alicyclic hydrocarbon such as is used. These may be used alone or in combination of two or more.
These foaming agents are usually used in an amount of 3 to 15% by weight based on the regenerated styrene resin particles.
[0035]
The impregnation temperature of the foaming agent is preferably 100 ° C. or higher, more preferably 110 ° C. or higher. When the impregnation temperature of the foaming agent is less than 100 ° C., the particles are difficult to spheroidize. Further, when the temperature is too high, the particles are easily united with each other. Therefore, the temperature is preferably 140 ° C or lower, and more preferably 130 ° C or lower.
After the impregnation with the foaming agent is completed, regenerated foamable styrene resin particles can be obtained by discharging from the polymerization system.
[0036]
After the regenerated foaming styrene resin particles are dehydrated and dried, a surface coating agent can be coated as necessary. As this coating agent, those used for conventionally known expandable styrene resin particles can be applied. For example, zinc stearate, stearic acid triglyceride, stearic acid monoglyceride, castor hardened oil, beef tallow hardened oil, silicones, antistatic agent and the like.
[0037]
The ratio of the regenerated styrene resin pellets to the regenerated expandable styrene resin particles (before impregnation with the foaming agent) is preferably 70% by weight or less, more preferably 60% by weight or less. If it exceeds 70% by weight, the particles are difficult to spheroidize. Further, when the ratio is too small, the particles are easily united in the polymerization process, and therefore, 20% by weight or more is preferable.
[0038]
The regenerated expandable styrene resin particles produced by the method of the present invention can be obtained as spherical particles, although regenerated styrene resin pellets shrinking in the length direction are used as the core of polymerization.
Therefore, regenerated expandable styrene resin particles can be produced using regenerated pellets obtained by a general molding method, regardless of a special method for producing unstretched regenerated styrene resin pellets.
[0039]
Next, the recycled foam molded product of the present invention will be described.
The regenerated foam molded article of the present invention is produced by foam molding regenerated foamable styrene resin particles.
In general, regenerated expandable styrene resin particles are heated with steam or the like to be pre-foamed to a predetermined bulk density, filled with foam beads that have undergone an aging process, and again heated and foamed with steam or the like, Manufacture foam molded products.
[0040]
【Example】
Next, the present invention will be described in more detail by way of examples.
The regenerated expandable styrene resin particles were evaluated by the following methods.
1. Pellet dimensions
Measured with calipers.
2. Pellet shrinkage
Pellets were put into a thermostat set at 200 ° C., taken out of the thermostat after heating for 10 minutes, the dimensions of the length before heating and after heating (pellet stretching direction) were measured, and obtained by the following calculation formula.
Pellet shrinkage = (dimension before heating−dimension after heating) / (dimension before heating) × 100
[0041]
3. Pellet ratio
It calculated | required with the following formula from the weight (W1) of the used reproduction | regeneration styrene-type resin pellet and the weight (W2) of the obtained reproduction | regeneration foamable styrene-type resin particle.
Pellet ratio = W1 / W2 x 100
4). Shape of resin particles after containing foaming agent
The length A of the longest part and the dimension B of the shortest part of the regenerated expandable styrenic resin particles are measured with a caliper, and when A / B = 0.8 to 1.3, it is determined to be spherical. When B was less than 0.8 or more than 1.3, it was determined to be flat.
In addition, the number of the measured particle | grains was 100 selected arbitrarily, and took the average value.
5. Surface smoothness of molded products
For the surface smoothness of the molded product, first, the surface of the molded product was thinly coated with printing ink with a roller, and this surface portion was applied to an image processing apparatus, and the area of the black portion relative to the total area was obtained to obtain the surface smoothness.
[0042]
Example 1
[Preparation of recycled styrene resin pellets]
The foamed styrene resin molded product was shrunk with hot air at 220 ° C. to obtain a shrunk product having an apparent specific gravity of 0.75, a size of 500 mm × 400 mm × 100 mm, and a weight of 15 kg. The shrinkage was coarsely pulverized by a pulverizer (product of Horai Co., Ltd., ZA-560 type pulverizer) equipped with a 10 mm screen. The maximum length of the coarsely pulverized product obtained at this time was approximately 10 mm and the bulk specific gravity was 0.5.
Next, 2000 g of this coarsely pulverized product, 20 g of talc (Hayashi Kasei Co., Ltd., White Micron # 5000) having an average particle size of 10 μm, and 0.6 g of ethylene bisstearyl amide are placed in a Henschel mixer (Mitsui Miike Chemicals, FM10B). For 2 minutes at 2000 rpm.
[0043]
The coarsely pulverized material whose surface was coated with talc and ethylenebisstearylamide was charged into the material feed section of a vented twin screw extruder (die hole diameter 2 mm, Ikegai PCM-30), and the cylinder temperature was 230 ° C. The material feed motor was extruded into strands under the conditions of a rotational speed of 8 rpm and a screw rotational speed of 100 rpm.
The strand was cut at a pelletizer rotational speed of 400 rpm to produce a regenerated styrene resin pellet. The length of the pellet in the stretching direction was 2.5 to 3.0 mm, and the diameter was 1.8 to 2.0 mm. Further, the dimensional shrinkage in the stretching direction after heating the pellet for 10 minutes at 200 ° C. was 12 to 17%.
[0044]
[Impregnation / polymerization process]
A 5 L pressure-resistant stirring vessel was charged with 1100 g of the regenerated styrene resin pellets, 1500 g of deionized water, 12.0 g of tricalcium phosphate and 0.09 g of sodium dodecylbenzenesulfonate, and the temperature was raised to 70 ° C. while stirring.
Next, 350 g of deionized water and 0.36 g of polyvinyl alcohol were mixed in a monomer dispersion container, and 200 g of a styrene monomer in which 3.2 g of t-butyl peroxide was dissolved was added thereto. The styrene monomer was finely dispersed (average monomer oil droplet diameter of 10 to 100 μm) by stirring at 5800 rpm for 120 seconds using an industrial product.
This styrene monomer dispersion was added to the container, kept warm for 90 minutes, and then heated to 90 ° C. Thereafter, 900 g of styrene monomer was continuously added at a constant rate (3.3 g / min) over 3 hours.
Subsequently, after adding 2.4 g of tricalcium phosphate and 0.05 g of sodium dodecylbenzenesulfonate, the temperature was raised to 115 ° C. and kept for 2 hours.
[0045]
Thereafter, it was cooled to 100 ° C., butane (isobutane / n-butane weight ratio = 4/6) as a blowing agent was injected in 160 g portions in two portions, held for 2 hours, then heated to 120 ° C., The foaming agent was impregnated for 8 hours.
After cooling to room temperature, the styrene resin particles impregnated with the blowing agent were taken out and dehydrated and dried. Next, the polymer particles were classified with a sieve having an opening of 2.8 mm and 1.2 mm to obtain 2080 g of resin particles. To the obtained resin particles, 1.1 g of zinc stearate and then 2.2 g of hardened castor oil were sequentially added and mixed to obtain regenerated expandable styrene resin particles. The regenerated expandable styrene resin particles obtained were spherical.
[0046]
[Recycled foamed styrene resin molded product]
The obtained regenerated expandable styrene resin particles were pre-expanded into 50 ml / g expanded beads by heating with steam using an expansion machine for expanded styrene resin (HBP-500LW manufactured by Hitachi Chemical Technoplant).
Then, after aging for about 18 hours, it was molded at a molding pressure of 0.08 MPa using a foamed styrene resin molding machine (Daisen Kogyo VS-300), and a recycled foamed styrene resin molded product (hereinafter referred to as a foam molded product). )
Table 1 shows the evaluation results of the regenerated styrene resin pellets, regenerated foamable styrene resin particles, and foamed molded products prepared in Example 1, Example 2 described later, and Comparative Examples 1 to 4.
[0047]
[Table 1]

[0048]
Example 2
In Example 1, the same operation as in Example 1 was performed except that the material feed motor rotation speed of the extruder was 1.5 rpm and the rotation speed of the pelletizer was 550 rpm, to obtain regenerated styrene resin pellets. The length of the pellet in the stretching direction was 2.5 to 3.0 mm, and the diameter was 0.8 to 1.1 mm. Further, the dimensional shrinkage in the stretching direction after heating the pellet for 10 minutes in a 200 ° C. atmosphere was 33 to 39%.
Using the regenerated styrene resin pellets, the same operation as in Example 1 was performed to obtain regenerated expandable styrene resin particles and a foam molded product.
[0049]
Comparative Example 1
In Example 1, the same operation as in Example 1 was performed except that the material feed motor rotation speed of the extruder was 1.2 rpm and the rotation speed of the pelletizer was 700 rpm, to obtain regenerated styrene resin pellets. The length of the pellet in the stretching direction was 2.8 to 3.3 mm, and the diameter was 0.6 to 0.9 mm. In addition, the dimensional shrinkage in the stretching direction after heating the pellet in a 200 ° C. atmosphere for 10 minutes was 65 to 72%.
Using the regenerated styrene resin pellets, the same operation as in Example 1 was performed to obtain regenerated expandable styrene resin particles and a foam molded product.
[0050]
Comparative Example 2
In Example 1, the same procedure as in Example 1 was performed except that the foaming agent was injected at 90 ° C. and maintained for 10 hours to impregnate the foaming agent. A molded product was obtained.
[0051]
Comparative Example 3
A 5 liter pressure-resistant stirring vessel was charged with 2000 g of deionized water, 1760 g of regenerated styrene resin pellets prepared in the same manner as in Example 1, 17.6 g of tricalcium phosphate, and 0.04 g of sodium dodecylbenzenesulfonate, and stirred. The temperature was raised to 75 ° C.
Next, 300 g of deionized water and 0.1 g of polyvinyl alcohol are mixed in a monomer dispersion container, and then 0.1 g of t-butyl peroxide and 300 g of styrene monomer in which 0.9 g of benzoyl peroxide are dissolved are added thereto. Then, the mixture was stirred for 120 seconds at 5800 rpm using a homomixer (manufactured by Koki Kogyo Kogyo Co., Ltd.) to disperse the styrene monomer finely (average diameter of monomer oil droplets of 10 to 100 μm). This styrene monomer dispersion was added to the container, kept warm for 60 minutes, and then heated to 90 ° C. Subsequently, 140 g of styrene monomer was continuously added at an equal rate (2.3 g / min) over 1 hour.
Subsequently, after adding 2.2 g of tricalcium phosphate and 0.05 g of sodium dodecylbenzenesulfonate, the temperature was raised to 115 ° C. and kept for 2 hours. Next, it is cooled to 100 ° C., 180 g of butane (i / n ratio = 4/6, weight ratio is the same) as a foaming agent is injected in two portions, held for 2 hours, then heated to 120 ° C. and foamed The agent was impregnated.
After cooling to room temperature, the regenerated expandable styrene resin particles impregnated with the foaming agent were taken out and dehydrated and dried.
Next, the polymer particles are classified with a sieve having an opening of 2.8 mm and 1.2 mm,
1520 g of resin particles were obtained. To the obtained resin particles, 1.1 g of zinc stearate and then 2.2 g of hardened castor oil were sequentially added and mixed to obtain regenerated expandable styrene resin particles.
Using the regenerated expandable styrene resin particles, the same operation as in Example 1 was performed to obtain a foam molded product.
[0052]
Comparative Example 4
In Example 1, the same operation as in Example 1 was performed except that the material feed motor rotation speed of the extruder was 8.5 rpm and the rotation speed of the pelletizer was 350 rpm, to obtain regenerated styrene resin pellets. The length of this pellet in the stretching direction was 6.5 to 7.8 mm, and the diameter was 2.6 to 3.4 mm. Further, the dimensional shrinkage in the stretching direction after heating the pellet for 10 minutes in a 200 ° C. atmosphere was 15 to 18%.
Using the regenerated styrene resin pellets, the same operation as in Example 1 was performed to obtain regenerated expandable styrene resin particles and a foam molded product.
[0053]
【The invention's effect】
According to the present invention, it is possible to provide a method for producing spherical regenerated foamable styrene resin particles from stretched pellets in the reuse of a foamed styrene resin molded article.

Claims (5)

Suspended in an aqueous medium with a regenerated styrene resin pellet having a columnar shape having a length of 5.0 mm or less and a diameter of 3.0 mm or less and a dimensional shrinkage in the length direction of 50% or less as a core. Let
The regenerated styrene resin pellets are impregnated with a polymerization initiator and a styrene monomer, and subsequently a styrene monomer is added to perform polymerization.
Thereafter, at the impregnation temperature of 100 ° C. or higher, a method for producing regenerated expandable styrene resin particles impregnated with a foaming agent,
The manufacturing method of the reproduction | regeneration foamable styrene resin particle whose ratio of the said reproduction | regeneration styrene resin pellet with respect to the said reproduction | regeneration foamable styrene resin particle is 70 weight% or less. Regenerated expandable styrene resin particles obtained by the method for producing regenerated expandable styrene resin particles according to claim 1. Regenerated styrene-based foam beads obtained by foaming the regenerated expandable resin particles according to claim 2. A regenerated expanded styrene resin molded product obtained by expansion molding of the regenerated styrene expanded beads according to claim 3. Recycled foamable styrene resin particles made of recycled styrene resin pellets having a columnar shape with a length of 5.0 mm or less and a diameter of 3.0 mm or less and a dimensional shrinkage in the length direction of 50% or less. The core used for manufacturing.