JP2009001693A - Plastic-molded article comprising regenerated plastic and elastic polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic-molded article comprising regenerated plastics and an elastic polymer, improved with physical properties such as impact resistance, flexibility, bending property, etc. <P>SOLUTION: The plastic-molded article comprises a regenerated plastics and an elastic polymer, wherein the regenerated plastics contain a polyethylene resin, polypropylene resin and polystyrene resin, and the total weight of the polyethylene resin, polypropylene resin and polystyrene resin is ≥90 wt.% based on the total weight of the regenerated plastics, and the plastic-molded article is provided by containing 50 to 99 wt.% regenerated plastics and 1 to 50 wt.% elastic polymer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a plastic molded article containing recycled plastic and an elastic polymer.

Due to the recent increase in awareness of the protection of the natural environment, the so-called Containers and Packaging Recycling Law (the Law Concerning the Collection and Recycling of Containers and Packaging) has been enforced, and the tendency to recycle used plastic is becoming stronger. . The following method is mentioned as a typical example of the method of recycling used plastic.
・ Use of recovered used plastic as a raw material component in a blast furnace (conversion to blast furnace raw material), method of using used plastic as a raw material component in a coke oven (conversion to coke oven chemical raw material), and can decompose used plastic to a monomer state Using plastic monomers again to make plastics (raw materials / monomerization), extracting and using hydrogen, methanol and other gases from used plastics (gasification), and reusing used plastics as naphtha Chemical recycling such as method (oilification).
-Thermal recycling, such as a method of preparing solid fuel using used plastic, and a heat-based incineration method using the used plastic as fuel.
-Material recycling in which used plastics are collected, passed through washing and sorting processes at a recycling plant, then recycled for each plastic of the same material, processed again and reused as recycled plastic products.

  Used plastics such as “Other plastic containers and packaging” (which may be abbreviated as “Ripura”), which are collected separately by the Containers and Packaging Recycling Law, are generally recycled as recycled plastic products. Chemical recycling such as blast furnace raw material conversion, coke oven chemical raw material conversion, raw material / monomerization, oil conversion or gasification has been performed.

  By the way, as such a used plastic recycling method, there is a social demand for a recycling method in which used plastic is used at a lower cost and at a higher rate. Used plastic is generally a mixture of various plastics. For this reason, recycled plastics that have been material-recycled with used plastics are also generally plastic mixtures containing various plastics. A plastic molded product molded using such recycled plastic has a problem that it is inferior in impact resistance and flexibility because it is a plastic mixture. This poor performance has been an obstacle to the expansion of recycled products made from recycled plastics.

  On the other hand, the plastic produced by raw material / monomerization in chemical recycling does not have the problem of being inferior in impact resistance and flexibility as described above. However, in raw materials and monomers in chemical recycling, there is a problem that the investment amount and running cost of the equipment are very high. Therefore, there is a problem that it cannot respond to a social request for a cheaper recycling method. In addition, in the raw material / monomerization in chemical recycling, a large amount of energy is required to decompose once polymerized to the monomer stage again. Therefore, there is also a problem that it does not conform to the current energy saving requirements.

  JP-A-2005-23191 (Patent Document 1) describes a polyolefin resin and / or a copolymer having a polyolefin skeleton, a polyvinyl chloride resin, an ionomer resin, an oxazoline-based compatibilizer, and an elastomer-based compatibilizer. A recycled plastic material comprising at least one compatibilizer selected from the group consisting of an agent and a reactive compatibilizer is described (claim 1). However, the used plastic used in this plastic material differs from the present invention in that it does not contain polystyrene resin. Further, the present invention improves the compatibility between the recycled plastic and the elastic polymer by using a recycled plastic containing polyethylene resin, polypropylene resin and polystyrene resin, and an elastic polymer. This is different from the invention described in 1.

JP-A-2005-23191

  The present invention aims to solve these problems, and an object of the present invention is to provide a plastic molded article containing recycled plastic and an elastic polymer having improved physical properties such as impact resistance, flexibility and bendability. .

The present invention
A plastic molded product containing recycled plastic and elastic polymer,
This recycled plastic contains polyethylene resin, polypropylene resin and polystyrene resin, and the total weight of polyethylene resin, polypropylene resin and polystyrene resin contained in this recycled plastic is 90% by weight or more with respect to the total weight of recycled plastic. Yes, and
Containing 50 to 99% by weight of this recycled plastic and 1 to 50% by weight of elastic polymer,
A plastic molded article is provided, whereby the above object is achieved.

  The recycled plastic preferably contains 45 to 65% by weight of polyethylene resin, 25 to 45% by weight of polypropylene resin, and 5 to 20% by weight of polystyrene resin.

  The elastic polymer is preferably one or more selected from the group consisting of recycled rubber, styrene butadiene rubber, ethylene-propylene rubber, styrene butadiene styrene block polymer, and styrene isoprene styrene block polymer.

  The plastic molded article is preferably obtained by mixing recycled plastic and an elastic polymer.

  The plastic molded article preferably has a hardness (type D) of 10 to 55.

  The plastic molded article of the present invention has good physical properties such as impact resistance, bendability and bendability despite being manufactured using recycled plastic obtained by material recycling. According to the present invention, it is possible to prepare a plastic molded product having such good physical properties using a recycled plastic obtained by material recycling. Therefore, it is possible to manufacture a plastic molded product that is a recycled product with a relatively low capital investment and running cost. The present invention makes it possible to recycle used plastics previously discarded or used as fuel by a cheaper method and with the added value of having good physical properties. The method of the present invention is an invention with high industrial utility value corresponding to the current demand for energy saving.

  The plastic molded article of the present invention is characterized by containing recycled plastic and an elastic polymer. The “recycled plastic” in this specification means a plastic obtained by material recycling. The material cycle is a recycling method in which used plastics are collected, subjected to a cleaning process and a sorting process in a recycling factory, recycled for each plastic of the same material, processed again, and reused as a recycled plastic product. For example, even plastics obtained using used plastics, plastics produced by raw materials and monomerization in chemical recycling are not included in “recycled plastics” in the present invention.

  Examples of the recycled plastic component include polyethylene resin, polypropylene resin, polystyrene resin, vinyl chloride resin, and their modified thermoplastic elastomers. The recycled plastic used in the present invention includes a polyethylene resin, a polypropylene resin, and a polystyrene resin. In the present invention, the total weight of these polyethylene resin, polypropylene resin and polystyrene resin contained in the recycled plastic is 90% by weight or more based on the total weight of the recycled plastic.

  The amount of polyethylene resin contained in the recycled plastic is preferably 45 to 65% by weight based on the total weight of the recycled plastic. When the amount of the polyethylene resin is less than 45% by weight, the melting temperature rises, the fluidity at the time of molding deteriorates, and it may be difficult to produce a fine molded product. Further, since a higher temperature is required as the temperature during kneading, it may be difficult to secure a heat source. Further, a special processing and molding machine is required due to an increase in melting temperature, which increases running costs and capital investment, and may make it difficult to supply inexpensive products. On the other hand, when the amount of the polyethylene resin exceeds 65% by weight, the obtained plastic molded product has insufficient rigidity, and there is a possibility that the usage of the plastic molded product is limited.

  The amount of polypropylene resin contained in the recycled plastic is preferably 25 to 45% by weight based on the total weight of the recycled plastic. When the amount of the polypropylene resin is less than 25% by weight, the obtained plastic molded product has insufficient rigidity, and there is a possibility that the usage of the plastic molded product is limited. On the other hand, when the amount of the polypropylene resin exceeds 45% by weight, the melting temperature rises, the fluidity at the time of molding deteriorates, and it may be difficult to produce a fine plastic molding. Further, since a higher temperature is required as the temperature during kneading, it may be difficult to secure a heat source.

  The recycled plastic used in the present invention contains a polystyrene resin. By including the polystyrene resin in the recycled plastic, the compatibility between the recycled plastic and the elastic polymer is improved, thereby obtaining a plastic molded article having excellent impact resistance and flexibility. The amount of polystyrene resin contained in the recycled plastic is preferably 5 to 20% by weight based on the total weight of the recycled plastic. When the amount of the polystyrene resin is less than 5% by weight, the compatibility between the recycled plastic and the elastic polymer is lowered, and there is a possibility that poor dispersion occurs. Furthermore, there is a possibility that the kneading time at the time of molding a plastic molded product becomes long. When the amount of the polystyrene resin exceeds 20% by weight, the impact property and flexibility of the obtained plastic molding may be inferior.

  Used plastics that are generally discarded at home and the like are mostly polyolefin-based, and occupy about half of all used plastics. In view of such a situation, it is most suitable to use a recycled plastic in which the amount of polyethylene resin is 45 to 65% by weight and the amount of polypropylene resin is 25 to 45% by weight with respect to the recycling ratio of the used plastic. ing.

  Although it does not limit as a preparation method of the said recycled plastic, For example, the following method is mentioned. An example of a separation method when supplying used plastic to the refining process will be described with reference to FIG. The used plastic 100 of the general waste that has been collected is subjected to processing such as magnetic separation as necessary, and then crushed to an appropriate size by the crusher 50. The crushed used plastic is separated into one having a small specific gravity and one having a large specific gravity, and a low specific gravity component is recovered. Such a separation process can be performed using, for example, a wet specific gravity separator.

  An example of a wet specific gravity separator that can be used for the separation treatment is shown in FIG. This is a separation apparatus that performs a separation process by specific gravity by a centrifugal separation method. In FIG. 2, a water 66 in which used plastic is dispersed is charged into a main body 60 configured to be rotatable. When the main body 60 rotates, a structure having a specific gravity greater than water (high specific gravity component) 101 gathers on the outer peripheral portion of the main body 60, and a specific gravity smaller than water (low specific gravity component) 102 gathers on the water surface (inside). ing. And what was gathered in the outer peripheral part and what gathered in the water surface part (inner side) are separately extracted with a screw, respectively, so that the used plastics charged are separated into those having a small specific gravity and those having a large specific gravity. . In FIG. 2, 62 is an inlet for water in which used plastic is dispersed, 63 is a screw that scrapes out high specific gravity components and low specific gravity components in the left and right directions, 64 is a discharge port for high specific gravity components, and 65 is a low specific gravity. It is an outlet for ingredients.

  By using such a specific gravity separator, PVC (polyvinyl chloride), PVDC (polyvinylidene chloride), PET (polyethylene terephthalate) and the like can be removed as a high specific gravity component from the collected used plastic. And the plastic which mainly contains polyolefin-type plastics, such as PE (polyethylene) and PP (polypropylene), can be obtained as a low specific gravity component. The low specific gravity component plastic 102 thus obtained is drained and then processed into a granular shape by the granulator 52. In this way, the used plastic 103 subjected to the separation process is obtained. The fractionated used plastic 103 obtained in this way mainly contains polyolefin plastics such as PE and PP.

  It is desirable that the fractionated used plastic thus obtained is then subjected to a purification treatment. As a purification process step of the used plastic after the separation treatment, for example, a step shown in FIG. In FIG. 3, the extruder 10 has an electrothermal heating means, and is connected to a vacuum pump for maintaining a part of the inside of the machine in a highly depressurized state, and has a function of heating the charge and the charge. It has a function to deaerate.

  In the refining process, the used plastic 103 subjected to the separation process is charged into the extruder 10 and heated to melt. The heating temperature of the used plastic that has been subjected to the sorting process varies depending on the type of plastic to be collected. The heating temperature is generally in the range of about 180 ° C. to 250 ° C. If a high melting point plastic other than polyolefin plastic is mixed, the heating temperature should be set lower than the melting point of the high melting point plastic. preferable.

  In the extruder 10, the water contained in the used plastic that has been charged evaporates, organic substances such as attached foods are volatilized or decomposed, and a part of the plastic is further decomposed. Gas that cannot be ignored, such as gasification. However, since the inside of the extruder 10 is sucked by the vacuum pump 14 and is in a highly decompressed state, the generated gas is sucked and exhausted without remaining in the molten used plastic. Since the exhausted gas contains a component that emits a bad odor, it is introduced into the deodorizing device 15 filled with the adsorbent and subjected to a deodorizing process.

  Next, the melt discharged from the extruder 10 is press-fitted into a filtration device 12 equipped with a screen by a gear pump 11 and filtered. By this filtration treatment, the solid matter 104 such as high melting point plastic or aluminum foil that could not be removed by the separation treatment in the previous step is removed. In this filtration process, it is preferable to arrange a plurality of screens having different mesh sizes in series in the order of large and small to perform multi-stage filtration to reduce clogging of the screen.

  The melt from which the solid material 104 has been removed is introduced into the granulator 13, and after being cooled and solidified by a hot cut method or a strand method, it is cut. In this way, a purified recycled plastic 105 can be obtained. The recycled plastic 105 does not contain a metal or a high melting point plastic that is present in a solid state when melted, and further, a malodor generating substance is removed. For this reason, by using this recycled plastic 105 as a material of a plastic molded product, a plastic molded product having excellent quality can be manufactured.

  Examples of the elastic polymer contained in the plastic molded article of the present invention include natural rubber, styrene butadiene rubber, butadiene rubber, acrylonitrile butadiene rubber, ethylene propylene rubber (such as ethylene-propylene terpolymer), butyl rubber, chloroprene rubber, Examples include silicone rubber, fluorine rubber, acrylic rubber, epichlorohydrin rubber, recycled rubber, styrene butadiene styrene block polymer, styrene isoprene styrene block polymer, urethane rubber, and other elastic polymer polymers. Two or more elastic polymers may be mixed and used. Among these, for example, recycled rubber, styrene butadiene rubber, ethylene propylene rubber, styrene butadiene styrene block polymer, styrene isoprene styrene block polymer, and the like are preferably used.

  Examples of the recycled rubber include butyl recycled rubber. By using such recycled rubber as an elastic polymer, there is an advantage that it is possible to form a plastic molded product having a very high recycling rate and excellent physical properties such as impact resistance and flexibility. Examples of the butyl recycled rubber that can be preferably used in the present invention include Hayakawa Rubber, butyl recycled rubber (Mooney viscosity 30 to 70), and the like.

  The plastic molded article of the present invention preferably contains 50 to 99% by weight of recycled plastic and 1 to 50% by weight of elastic polymer. When the amount of the elastic polymer is less than 1% by weight, the impact resistance and flexibility of the plastic molded product may be deteriorated. On the other hand, when the amount of the elastic polymer exceeds 50% by weight, the rigidity required for the plastic molded product is not exhibited, and there is a possibility that the plastic molded product is not suitable for use.

  The plastic molded article of the present invention may contain additives such as fillers and softeners as necessary. Examples of the filler that can be used include fillers such as calcium carbonate, clay, talc, magnesium carbonate, barium sulfate, mica, aluminum hydroxide, silicon oxides, and silica sand. Two or more fillers may be mixed and used as the filler.

  Examples of softeners that can be used include plant softeners, mineral oil softeners, and synthetic plasticizers. Two or more softening agents may be mixed and used. Furthermore, additives such as anti-aging agents, stabilizers and processing aids may be added as necessary.

  The plastic molded product of the present invention preferably has a hardness (type D) of 10 to 55. When the altitude (type D) is less than 10, the rigidity is insufficient and the plastic molded product may be inappropriate. Moreover, when hardness (type D) exceeds 55, there exists a possibility that impact property and flexibility may be inferior. The hardness (type D) of a plastic molded product can be measured according to, for example, JIS K 6253.

  Examples of the method for producing a plastic molded product of the present invention include a method in which an elastic polymer and a recycled plastic are mixed in advance and then the resulting mixture is molded. For example, the recycled plastic and the elastic polymer are mixed at a temperature of, for example, 150 to 250 ° C. with a mixer such as a kneader or a Banbury mixer, and processed into a predetermined size by an extruder. In this way, a compound containing an elastic polymer and recycled plastic can be obtained. There is also a method in which a pelletized recycled plastic and an elastic polymer are simultaneously put into an extruder or the like to obtain a compound having a predetermined size.

  By processing and molding the compound containing the elastic polymer and the recycled plastic thus obtained with an extruder, an injection molding machine, a press or the like, a plastic molded product having a desired shape can be obtained.

  The following examples further illustrate the present invention, but the present invention is not limited thereto. In the examples, “parts” and “%” are based on weight unless otherwise specified.

Examples 1-7 and Comparative Examples 1-3
The recycled plastic and the elastic polymer were blended in the amounts shown in the following table, heated to 160 ° C. with a 1 L pressure kneader, and kneaded for 10 minutes. Thereafter, extrusion was performed with a 75 mm biaxial extruder at a head temperature of 140 ° C., and extrusion into a sheet having a thickness of 2 mm and a width of 100 mm was made.

※ 各成分の品番及びメーカー名
・再生プラスチック：ＰＥ／ＰＰ／ＰＳ＝５３／３７／１０（重量比）、ＪＦＥ環境株式会社
・再生ゴム：ブチル再生ゴム、早川ゴム株式会社
・ＥＰＴ：エチレン−プロピレンゴム、ＥＰＴ ５７Ｃ、ＪＳＲ株式会社
・ＳＩＳブロックポリマー：スチレン−イソプレン−スチレンブロックポリマー、クレイトン １１０７、ＪＳＲ株式会社
・ＳＢＲ：スチレン−ブタジエン−ゴム、ＳＢＲ １５０２、ＪＳＲ株式会社
・ＳＢＳブロックポリマー：スチレン−ブタジエン−スチレン−ブロックポリマー、クレイトン １１０２、ＪＳＲ株式会社
・炭酸カルシウム：軽質炭酸カルシウム、白石工業株式会社
・軟化剤：鉱物油（パラフィン系）軟化剤、ＰＳ−３２、出光興産株式会社

* Part number and manufacturer name of each component / Recycled plastic: PE / PP / PS = 53/37/10 (weight ratio), JFE Environmental Co., Ltd./Recycled rubber: Butyl recycled rubber, Hayakawa Rubber Co., Ltd./EPT: Ethylene-propylene Rubber, EPT 57C, JSR Corporation, SIS block polymer: Styrene-isoprene-styrene block polymer, Kraton 1107, JSR Corporation, SBR: Styrene-butadiene-rubber, SBR 1502, JSR Corporation, SBS block polymer: Styrene-butadiene -Styrene-block polymer, Kraton 1102, JSR Corporation-Calcium carbonate: Light calcium carbonate, Shiroishi Kogyo Co., Ltd.-Softener: Mineral oil (paraffinic) softener, PS-32, Idemitsu Kosan Co., Ltd.

  Evaluation was performed as follows using the obtained specimens.

Tensile Stress and Elongation Test specimens obtained in the above Examples and Comparative Examples were punched out with a No. 1 dumbbell to prepare a measurement sample. About the obtained measurement sample, tensile stress and elongation were measured at a speed of 500 mm / min using a tensometer (manufactured by Shimadzu Corporation).

Hardness The hardness of the specimens obtained in the above Examples and Comparative Examples was measured using a hardness meter type D according to JIS K 6253.

Impact Resistance Test An impact resistance test was conducted using a weight drop tester specified in JIS K 5600-5-3. A weight (300 g) was dropped from a height of 550 mm on the test specimens (thickness 2 mm × Ф 40 mm) obtained in the above examples and comparative examples. The presence or absence of abnormality of the sample generated by the drop test was visually confirmed.

  As shown in the above table, it can be confirmed that the plastic molded product containing the recycled plastic and elastic polymer of the present invention has excellent physical properties such as tensile stress and elongation, and also has excellent impact resistance. It was. On the other hand, the plastic molded product of Comparative Example 1 containing no elastic polymer was inferior in impact resistance. In Comparative Examples 2 and 3 in which the amount of the elastic polymer exceeds 50% by weight, the physical properties of elongation are excellent, but the hardness is very low and the practicality as a plastic molded product is lacking.

  The plastic molded article of the present invention has good physical properties such as impact resistance, bendability and bendability despite being manufactured using recycled plastic obtained by material recycling. According to the present invention, it is possible to prepare a plastic molded product having such good physical properties using a recycled plastic obtained by material recycling. Therefore, it is possible to manufacture a plastic molded product that is a recycled product with a relatively low capital investment and running cost. The present invention makes it possible to recycle used plastics previously discarded or used as fuel by a cheaper method and with the added value of having good physical properties. The method of the present invention is an invention with high industrial utility value corresponding to the current demand for energy saving. Furthermore, since the plastic molded product obtained by the present invention does not contain halogen and other substances subject to laws and regulations, it has an advantage that it is environmentally friendly and can be recycled and commercialized again.

It is a figure which shows an example of the method of classifying a used plastic. It is a figure which shows the structure of a centrifugation system wet specific gravity separator. It is a figure which shows an example of the refinement | purification process of the used plastic by which the separation process was carried out.

Explanation of symbols

10: Extruder,
11 ... Gear pump,
12 ... Filtration device,
13 ... Granulator,
14 ... vacuum pump,
15 ... deodorizing device,
50 ... Crusher,
51. Specific gravity separator,
52 ... Granulator,
60 ... the body,
62 ... Inlet,
63 ... Screw,
64 ... High specific gravity component outlet,
65: Low specific gravity component outlet,
66 ... water,
100 ... used plastic recovered,
101 ... high specific gravity component,
102 ... Low specific gravity component,
103 ... used plastic after separation,
104: unmelted material,
105: Recycled plastic.

Claims (5)

A plastic molded product containing recycled plastic and elastic polymer,
The recycled plastic contains polyethylene resin, polypropylene resin and polystyrene resin, and the total weight of polyethylene resin, polypropylene resin and polystyrene resin contained in the recycled plastic is 90% by weight or more based on the total weight of the recycled plastic. Yes, and
Containing 50 to 99% by weight of the recycled plastic and 1 to 50% by weight of an elastic polymer,
Plastic molded product.   2. The plastic molded product according to claim 1, wherein the recycled plastic includes 45 to 65 wt% polyethylene resin, 25 to 45 wt% polypropylene resin, and 5 to 20 wt% polystyrene resin. 3.   The elastic polymer is one or more selected from the group consisting of recycled rubber, styrene butadiene rubber, ethylene-propylene rubber, styrene butadiene styrene block polymer, and styrene isoprene styrene block polymer. Plastic molded product.   The plastic molded product according to any one of claims 1 to 3, which is obtained by mixing recycled plastic and an elastic polymer.   The plastic molded product according to any one of claims 1 to 4, wherein the plastic molded product has a hardness (type D) of 10 to 55.

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