JP2010070684A - Biomass plastic material and method for producing biomass plastic molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biomass plastic material which is suitable for blow molding and excellent in moldability, is well environment-friendly by reducing the degree of dependence on fossil fuels and having high biodegradability, and has lower cost, and to provide a method for producing biomass plastic molded products. <P>SOLUTION: The biomass plastic material is produced by adding a crosslinkable polymer to a mixture in which a biomass plastic material based on a rice starch having biodegradability is melt blended with a noncrosslinkable polymer such as polypropylene. In the crosslinkable polymer, crosslinking treatment with electron beam irradiation is conducted. The biodegradable resin biomass plastic molded product is produced by melt blending the produced biomass plastic material again and by blow molding. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a biomass plastic material and a biomass plastic molded product, and more particularly, to an environment-friendly biomass plastic material and a method for producing a biomass plastic molded product made mainly from plant-derived raw materials.

  Plastic products derived from fossil fuels are widely used because they are lightweight, inexpensive and have good moldability. For example, beverage bottles made mainly of polyethylene terephthalate are very lightweight compared to glass bottles, so they are easy to carry, are produced in large quantities, and contribute greatly to the lives and distribution of consumers. is doing.

  However, as a result of being used in large quantities and in large quantities as described above, problems such as the depletion of fossil fuels such as petroleum and environmental problems such as the generation of large amounts of garbage after use due to poor biodegradability occur. Solving these problems is an important issue all over the world.

From the viewpoint of protecting the natural environment as described above, it is strongly desired to develop a product using a material that has low dependence on fossil fuel and is excellent in biodegradability, instead of a plastic product that has been conventionally used.
As an alternative to such conventional plastic products, biodegradable plastic products based on polylactic acid have been proposed.
This plastic based on polylactic acid is a so-called biomass plastic that can be extracted in large quantities from plants such as corn and potatoes, and has an excellent dependency on fossil fuels such as petroleum compared to conventional plastics. Have a face. Moreover, since the plant used as a raw material absorbs carbon dioxide during growth, it is also useful for preventing global warming, which has become a problem in recent years. Furthermore, since most of them have high biodegradability that is decomposed in the soil, they are favorably accepted as environmentally friendly products.

However, due to the recent increase in demand for biodegradable plastics and biofuels, there is a situation that the supply of polylactic acid cannot catch up with the market. For this reason, it is difficult to secure polylactic acid, and also causes problems such as high prices.
Therefore, as a practical problem, there is a demand for practical application of a product using a material that replaces the polylactic acid.

  As an alternative to such polylactic acid, biomass plastic derived from starch contained in plants has been developed. Since the biomass plastic mainly composed of starch is derived from plants like polylactic acid, it is possible to solve various problems such as fossil fuel depletion, global warming and dust problems. In addition, since it can be easily produced as compared with that of polylactic acid, it is expected to be an inexpensive material that can be supplied in large quantities.

As such a biomass plastic mainly composed of starch, a rice-blended polyolefin resin composition disclosed in Patent Document 1, a production method thereof, a film molded product thereof, and a molding method of this molded product have been proposed.
The rice-blended polyolefin resin composition disclosed in Patent Document 1 is based on polyolefin resin and rice, and polyolefin resin produced from fossil fuel by using surplus rice that is in need of disposal It is possible to reduce the amount of use. In addition, the molded product of this rice-blended polyolefin resin composition suppresses the generation of combustion heat and carbon dioxide even if it is incinerated, and it is easy to be decomposed even if it is landfilled. it can.
JP-A-2005-330402

  However, the above-mentioned rice-blended polyolefin resin composition has many problems in terms of heat resistance and strength, and its fluidity is high, so it is difficult to say that it is suitable for all molding methods. In particular, when molding is performed by blow molding which is generally performed, the moldability becomes a problem.

  The present invention has been made in view of the above problems, and has excellent moldability suitable for blow molding, and also has sufficient biodegradability by reducing dependence on fossil fuels, giving sufficient consideration to the environment. Another object of the present invention is to provide a method for producing a biomass plastic material and a biomass plastic molded product that achieves cost reduction.

  In order to achieve this object, the present invention is a resin material used for blow molding, and is produced by melt-kneading rice starch, a non-crosslinkable polymer and a crosslinkable polymer subjected to a crosslinking treatment. And

  Moreover, the biomass plastic material in the present invention uses polypropylene as a non-crosslinkable polymer, linear low density polyethylene as a crosslinkable polymer, 40-80% by weight of rice starch, 10-30% by weight of polypropylene, and subjected to a crosslinking treatment. It is produced by mixing 10 to 30% by weight of the applied linear low density polyethylene.

  According to the present invention, the crosslinking treatment is characterized by using an irradiation crosslinking method in which ionizing radiation is irradiated or a chemical crosslinking method in which an organic peroxide is used as a crosslinking agent.

  In addition, the method for producing a biomass plastic molded product according to the present invention includes a crosslinking step in which a crosslinkable polymer is subjected to a crosslinking treatment, rice starch, a crosslinkable polymer that has been subjected to a crosslinking treatment, and a non-crosslinkable polymer, and then cooled. It has a solid production | generation process which produces | generates a solid substance, and the shaping | molding process which melt-kneads the solid substance produced | generated by the solid production | generation process, and performs blow molding.

  Further, according to the present invention, the solid production step uses polypropylene as the non-crosslinkable polymer and linear low density polyethylene as the crosslinkable polymer, and contains 40 to 80% by weight of rice starch and 10 to 30% by weight of polypropylene. The linear low density polyethylene is 10 to 30% by weight.

  According to the present invention, the molding step is characterized in that the cross-linked solid material is melt-kneaded at 160 to 170 ° C., extruded and molded.

  According to the present invention, biodegradability and strength resistance can be obtained by adding a crosslinkable polymer that has been subjected to a crosslinking treatment by irradiating an electron beam to a mixture of rice starch and non-crosslinkable polymer excellent in biodegradability. It is possible to provide a biomass plastic material excellent in heat resistance and blow moldability.

<Outline of the present embodiment>
In the embodiment of the present invention, a biomass plastic material having not only biodegradability but also strength and heat resistance exceeding a predetermined level and excellent moldability suitable for blow molding is generated, and this biomass plastic material is blown. A biomass plastic molding such as a bottle container is manufactured by molding or the like.
Hereinafter, the “composition of the biomass plastic material” and the “manufacturing method of the biomass plastic molded product” will be described in detail, and further the specific examples (Examples 1, 2, and 3) of the present embodiment will be described.

<Composition of biomass plastic material>
First, the composition of the biomass plastic material in the embodiment of the present invention will be described.
Biomass plastic material in the present embodiment is a crosslinkable polymer such as polyethylene irradiated with an electron beam into a mixture obtained by melting and kneading a non-crosslinkable polymer such as polypropylene into a main material of rice starch having biodegradability. Is generated.

Since this biomass plastic material has biodegradable and easily available rice starch as a main material, it is possible to easily provide an environmentally friendly resin material.
Moreover, since this biomass plastic material contains the crosslinkable polymer which crosslinks by electron beam irradiation, it is possible to improve the strength and heat resistance of the molded biomass plastic product.
Furthermore, since this biomass plastic material contains a non-crosslinkable polymer that maintains a predetermined degree of stretching even after electron beam irradiation, it has excellent moldability suitable for blow molding.

  In order to increase the compatibility with the crosslinkable polymer and the non-crosslinkable polymer, the rice starch that is the main material of the biomass plastic material in the present embodiment is immersed in water and boiled, or steamed with raw rice The water content is preferably 17% or more and gelatinized (gelatinized).

  The said non-crosslinkable polymer is a polymer which does not have radically polymerizable functional groups, such as an ethylenic double bond, Comprising: For example, 1 or 2 types of polypropylene, a polystyrene, polyethyleneglycol, or poly (N-isopropylacrylamide) A mixture of the above is used.

  The crosslinkable polymer is a polymer that undergoes a crosslinking reaction by electron beam irradiation or the like. For example, linear low density polyethylene (LLDPE), low density polyethylene (HPPE), high density polyethylene (HDPE), etc. One or a mixture of two or more kinds of polyethylene, ethylene-based copolymers such as ethylene-vinyl acetate copolymer (EVA) or ethylene-ethyl acrylate copolymer (EEA), and polybutylene succinate ( PBS), polybutylene succinate adipate (PBSA), aromatic dicarboxylic acid-based polyester elastomer and the like, or a mixture of two or more.

  Moreover, since it changes to brown when high heat is applied to rice starch, the non-crosslinkable polymer and the crosslinkable polymer preferably have a melting point of 150 ° C. or lower. For example, it is preferable to use polypropylene as the non-crosslinkable polymer and linear low density polyethylene (LLDPE) as the crosslinkable polymer.

Moreover, it is preferable to add a compatibilizing agent as appropriate in order to enhance the compatibilizing property between rice starch and the various resins described above.
As the compatibilizing agent, for example, a saturated carboxylic acid, an unsaturated carboxylic acid or a derivative thereof is used. This compatibilizing agent is preferably added in an amount of about 0.1 to 20% by weight with respect to 100% by weight of the total amount of rice starch, crosslinkable polymer and non-crosslinkable polymer.

  Further, in order to impart biodegradability to the crosslinkable polymer and the non-crosslinkable polymer, a biodegradability imparting agent may be appropriately added. Examples of the biodegradability-imparting agent include monosaccharides such as glucose, galactose, mannose and fructose, disaccharides such as maltose, lactose and sucrose, polysaccharides such as starch, dextrin, cellulose, inulin, agarose and fructan, chitin and chitosan And amino sugars such as amikacin and sisomaxin, reducing sugars such as aldose, ketose and heptose, and sugar alcohols such as detritol and pentitol.

<Manufacturing method of biomass plastic molding>
Next, the manufacturing method of the biomass plastic molding in this Embodiment is demonstrated.
In the present embodiment, as an example, the bottle container is molded using a direct blow molding method.

First, the above-mentioned pregelatinized rice starch and non-crosslinkable polymer are 130 to 200 ° C., preferably 150 to 190 ° C., 20 seconds to 30 minutes, preferably 30 seconds to 20 minutes, using a single or twin screw extruder or the like. Heat knead.
At this time, if necessary, an additive can be appropriately added to the mixture of the rice starch and the non-crosslinkable polymer. For example, as this additive, a compatibilizer for improving the affinity at the interface between pregelatinized rice starch and a non-crosslinkable polymer, and imparts biodegradability to the non-crosslinkable polymer and the crosslinkable polymer described later. For example, a biodegradability-imparting agent is added.

  When a mixture of the rice starch and the non-crosslinkable polymer is melt-kneaded with an extruder or the like, the rice starch is refined in a matrix of the heat-flowable non-crosslinkable polymer to obtain a uniformly dispersed state. From this state, for example, it is formed into pellets or granules and cooled to room temperature to solidify, and a mixture of rice starch and non-crosslinkable polymer is obtained.

  Next, the pellet-like or granular solid crosslinkable polymer is irradiated with an electron beam of 10 to 50 kGy to carry out a crosslinking treatment.

Next, the pellet-like or granular solid crosslinkable polymer subjected to the crosslinking treatment and the aforementioned pellet-like or granular solid mixed material are mixed at a predetermined ratio.
With the above, a biomass plastic material having aptitude excellent in blow molding can be obtained.

  Next, the biomass plastic material obtained as described above is blow-molded as follows to obtain a biomass plastic molded product.

  First, the above-mentioned biomass plastic material is heated and kneaded with an extruder, and as a molten parison while maintaining the temperature of the molten mixture in the range of melting point to melting point + 10 ° C, preferably melting point + 5 ° C, in an unmelted state. Extrude continuously.

The continuously extruded molten parison is supplied to an open split mold for molding, the split mold is closed and the molten parison is clamped (held) at the neck, and the bottom surface is pinched off (melt cut). By doing so, the parison bottom part used as a container bottom part is formed.
Note that the molten parison may be slightly inflated (pre-blow) when it is clamped with a split mold in order to improve the cut-off property and the clamp property.

Next, when the molten parison clamped to the split mold is pressed against the blowing port of the molten parison and a gas such as compressed air is blown to blow up the molten parison, it is cooled and solidified simultaneously with expansion. Thus, for example, a cylindrical biomass plastic molding is formed.
Then, the blowing nozzle is released, the gas pressure is released, the split mold is opened, and the biomass plastic molded product is taken out.
Thus, the biomass plastic molding is completed.

  According to the present embodiment, a biomass plastic material is obtained by adding a crosslinkable polymer that has been subjected to a crosslinking treatment by irradiating an electron beam to a mixture of non-crosslinkable polymers such as rice starch and polypropylene excellent in biodegradability. Therefore, it is possible to obtain this biomass plastic material excellent in strength resistance and heat resistance.

In addition, according to the present embodiment, the biomass plastic material has a predetermined degree of stretching because it contains a non-crosslinkable polymer such as polypropylene.
Accordingly, the biomass plastic material in the present embodiment has the above-described excellent strength resistance and heat resistance, and the molten parison using this biomass plastic material has a predetermined shape stability and a suitable degree of stretch and is suitable for blow molding. Since it has moldability, it becomes possible to produce a biomass plastic molded article having a uniform film thickness, a beautiful appearance, and excellent quality with few defects such as cracks and pinholes.

In the present embodiment, both the mixture of rice starch and non-crosslinkable polymer and the crosslinkable polymer are pellets or granular solids in a dry state, so that mixing at a ratio according to the purpose is easy. It is.
For example, when polypropylene is used as the non-crosslinkable polymer and linear low density polyethylene (LLDPE) is used as the crosslinkable polymer, the blending ratio is 40 to 40 kg of rice starch in a dry state (in pellet form or granular molding). 80% by weight, 10-30% by weight of polypropylene and 10-30% by weight of linear low density polyethylene (LLDPE), preferably 56% by weight of rice starch, 24% by weight of polypropylene, linear low Density polyethylene (LLDPE) is 20% by weight.

  Also, in general, it is difficult to set up an electron beam irradiation facility in a plastic molding factory for administrative and economic reasons. Biomass plastic with excellent strength and heat resistance even in molding factories that do not have electron beam irradiation facilities by irradiating with electron beams at the material stage before molding and supplying them to plastic molding factories It becomes possible to mold the molded product.

As described above, the biomass plastic molded product in the present embodiment is molded by direct blow molding. The co-extruded multilayer parison is sandwiched between split molds, and the pressurized fluid is placed in the parison. Biomass plastic moldings can also be molded by so-called coextrusion multilayer blow molding, which is introduced and expanded.
When molding this multilayer blow-molded product, the biomass plastic material in the present embodiment is used for the outer layer, and the inner layer (core layer) is molded using a material suitable for the application. For example, when extremely high gas barrier properties are required by regulations, such as sealed containers for foods, etc., a resin such as polyethylene specified in the regulations, etc. is used for the inner layer that is in direct contact with the contents of the food, etc. The biomass plastic material in the present embodiment is used.
In this way, even when non-biomass plastic such as polyethylene is specified as the material of the container, molding is made in consideration of the environment by minimizing that part and making the other part a biomass plastic material. Objects can be molded.

  Moreover, the biomass plastic molding in this Embodiment can also be shape | molded by injection blow molding. In this case, a preform is molded by injection using the biomass plastic material in the present embodiment, and blow molding is performed by blowing air into the molded preform.

In addition, although the biomass plastic molding in this Embodiment demonstrated the example produced by blow molding, multilayer blow molding, or injection blow molding, the molding method is not limited to these, It shape | molds by another shaping | molding method You can also
Moreover, when shape | molding the cap part etc. of a bottle using a biomass plastic material, it is preferable to shape | mold by injection molding (injection molding) or injection blow molding.

Example 1
1. Production conditions of biomass plastic material As a mixture of rice starch and non-crosslinkable polymer, polypropylene is mixed with pregelatinized raw rice, and a compatibilizer and biodegradability-imparting agent are added (Agriwood Resource Rice) Type (SRP70-3F): agrifuture manufactured by Joetsu Co., Ltd. was used. This rice mixture was prepared by mixing and adding 70% by weight of raw rice, 27% by weight of polypropylene, 2.2% by weight of a compatibilizer, and 0.8% of a biodegradability imparting agent.

Next, 20% by weight of linear low density polyethylene (LLDPE) (UE-320: manufactured by Nippon Polychem) was mixed as a crosslinkable polymer with respect to 80% by weight of the mixed material.
The mixture was irradiated with an electron beam of 30 kGy by an electron accelerator (acceleration voltage 2 MeV, current value 1 mA) under an inert atmosphere excluding air to obtain a biomass plastic material.

2. Production conditions for biomass plastic molding The biomass plastic material obtained as described above was blow-molded to obtain a biomass plastic molding.
In this example, the resin was extruded from the extruder into a mold as shown below.
First, the resin is introduced into a cylinder adjusted to the melting point of the resin or higher from an inlet called a hopper, melted and kneaded in the cylinder, then passed through the flange and the head and the die in this order, and the most advanced of the extruder. Extruded from the lip into the mold.
The cylinder used was composed of three cylinders 1, 2, 3 from the upstream side to the downstream side in the extrusion direction. In this example, the temperature was adjusted independently for each cylinder.

The molding conditions in this example were as follows.
Molding machine (extruder + mold): VTD-250 (Maywa Shoko)
Melting and kneading temperature: Cylinder 1 160 ° C
: Cylinder 2 165 ° C
: Cylinder 3 170 ° C
: Flange 160 ° C
: Head 170 ° C
: Dice 165 ° C
: Lip 40 ° C
Blowing time 14 seconds

As described above, the temperatures of the cylinders 1 to 3 were set so that the temperature in the cylinder gradually increased from 160 ° C. to 165 ° C. to 170 ° C. in the extrusion direction.
As described above, by setting the temperature of the molding machine (extruder) and adjusting the blowing time, it was possible to obtain a beautiful resin molded product having a high gas barrier property.

3. Measurement result of MFR (melt flow rate) of biomass plastic material The MFR of the biomass plastic material obtained as described above was measured, and the moldability when performing blow molding using the biomass plastic material was examined.
MFR is a physical property value measured by “Testing Method for Melt Flow Rate (MFR) and Melt Volume Flow Rate (MVR) of Plastics—Thermoplastic Plastics” (JIS-K7210) specified by Japanese Industrial Standards (JIS). Point to. Specifically, it is the amount of a substance defined by the amount of resin (g) that flows out during a certain period of time when a load is applied in the temperature range in which the plastic flows, and is expressed by the following formula 1.

(Formula 1)

t _ref is the reference time (600 seconds = 10 minutes) for measuring the resin (biomass plastic material) flowing out, t is the resin cutting time interval (seconds), m is the amount of resin flowing out during the time t seconds (g) is there.

This MFR measurement was performed under the following conditions.
As a measuring instrument, IMC-1540C (manufactured by Imoto Seisakusho) was used.
The biomass plastic material inserted into a cylinder provided vertically in this measuring device was loaded with a piston on which a weight was placed, and extruded from a die (a small hole exit jig) to measure MFR.
The die was tungsten carbide with a length of 8.000 mm ± 0.025 mm and the diameter was within 0.005 mm with a nominal value of 2.095 mm. The temperature in the cylinder was 230 ° C., and the piston load was 2.16 kgf.
In addition to the biomass plastic material of this example, the following resin materials were used as comparative examples.
Comparative Example 1: High-density polyethylene (HDPE) (8300A: manufactured by Tosoh Corporation), electron beam non-irradiated Comparative Example 2: High-density polyethylene (HDPE) (8300A: manufactured by Tosoh Corporation), electron-beam irradiated Comparative Example 3: linear low Density polyethylene (LLDPE) (UE-320: manufactured by Nippon Polychem), non-irradiated with electron beam Comparative Example 4: Linear low-density polyethylene (LLDPE) (UE-320: manufactured by Nippon Polychem), irradiated with electron beam Table 1 below shows the MFR measurement results of the biomass plastic materials and the resins of Comparative Examples 1 to 4.

In general, a resin having an MFR of about 0.100 to 2.000 (g / 10 min) can be used for blow molding, and in particular, a resin having an MFR of about 0.300 to 0.500 (g / 10 min). It is preferable to use it.
As shown in the measurement results in the above table, the MFR of the biomass plastic material in this example is 0.340 (g / 10 min) and has fluidity (MFR) that is very suitable for blow molding. I understood it.
Therefore, when a container or the like was molded using this biomass plastic material, it was possible to obtain a so-called “stiff” molten parison having excellent stretchability and not being drawn down by its own weight.
Moreover, MFR of high density polyethylene was 0.404 (g / 10min), and MFR of linear low density polyethylene was 1.040 (g / 10min). From this measurement result, the biomass plastic material in this example has substantially the same or better moldability as compared with high-density polyethylene and linear low-density polyethylene, which are resins derived from 100% fossil fuel. I understood it.

4). Comparison of Heat Resistance of Biomass Plastic Molded Products Next, the heat resistance of the biomass plastic molded products formed in the bottle-type containers and other resin materials as comparative examples were measured and compared.
FIG. 1 is a side view of a heat resistance inspection jig 10 used when measuring the heat resistance of this biomass plastic molded product and another resin material as a comparative example.
As shown in the drawing, the heat resistance inspection jig 10 positions a measurement position of the container 20 on the plate-shaped base plate 11 on which the container 20 to be measured for heat resistance is placed. A guide 12, a bar-like member standing substantially perpendicular to the base plate 11, a height adjustment bar 13 for adjusting the height of a load bar 15, which will be described later, and the height adjustment bar 13 A plurality of shaft members 14 provided substantially vertically (substantially horizontal with respect to the base plate 11), and pivotally mounted in any of the plurality of shaft members 14 in the direction of arrow A in FIG. A load bar 15 that applies a load to the container 20 and a measurement bar 16 that is erected substantially vertically on the base plate 11 and provided with a scale indicating the height, like the height adjustment bar 13 described above. Is done.

Using the heat resistance inspection jig 10 configured as described above, a heat resistance measurement experiment of the bottle-shaped container 20 formed of each resin material was performed by the following method.
First, the guide 12 is slid in the direction of arrow B on the base plate 11 and fixed at a predetermined position, and the bottle-shaped container 20 is placed on the base plate 11 while being in close contact with the guide 12, The container 20 was positioned on the plate 11.
Next, the other end of the load bar 15 having a total weight of 5 kg, which is provided with a weight of a predetermined weight at one end, is pivotally attached to the shaft member 14 at a position slightly higher than the height of the container 20 of the base plate 11 and is directly attached to the container 20. It was rotated vertically downward until contacted, and a load was applied to the container 20.
With the start of this weighting, the scale of the measurement bar 16 was read, and the height of the container 20 placed on the base plate 11 was measured.
Then, after 1 minute with the load applied, the scale of the measurement bar 16 is read, the height of the container 20 placed on the base plate 11 is measured, and the load bar 15 is rotated upward to apply the load. finished.
Next, the measured value at the end of weighting was subtracted from the measured value at the start of weighting, and the difference was calculated.

  With the measurement method described above, the calculated value of the difference was obtained for each resin under a plurality of temperature conditions. That is, in this measurement experiment, it can be said that the lower the calculated value, the more difficult the bottle-shaped container is deformed under the measurement temperature condition, and it has excellent heat resistance.

In this measurement experiment, the heat resistance of the following Comparative Examples 1 to 5 in which a resin material was molded into a bottle-shaped container was measured together with the biomass plastic molded product in this example.
Biomass plastic molding in this example: 20% high density polyethylene (HDPE) (8300A: manufactured by Tosoh) as a crosslinkable polymer, Agriwood resource rice type SRP70-3F: agrifuture as a mixture of rice starch and non-crosslinkable polymer・ 80% made by Jyoetsu was used.
Comparative Example 1: High-density polyethylene (HDPE) (8300A: manufactured by Tosoh Corp.), non-irradiated with electron beam Comparative Example 2: Polylactic acid-containing resin (Foseas J9503J: manufactured by Mitsubishi Chemical), non-irradiated electron beam Comparative Example 3: Polylactic acid-containing resin (Fozeas J9503JT: manufactured by Mitsubishi Chemical), electron beam irradiation after molding, TAIC (triallyl isocyanurate) 3% mixed Comparative Example 4: Rice Starch-Containing Resin (Agriwood Resource Rice Type SRP70-3F: Agrifuture Jyoetsu) Comparative example 5: Rice starch-containing resin (Agriwood resource rice type SRP70-3F: manufactured by Agrifuture / Jyoetsu), electron beam irradiation after molding, TAIC 3% dry blend. It means that the granular or powdery resins are uniformly mixed.
Table 2 below summarizes the samples used in these measurement experiments.

First, in the state which removed the cap of the biomass plastic molding in the above-mentioned Example and Comparative Examples 1 to 5 and opened the cap, the above-mentioned was performed under two types of temperature conditions of 20 ° C. and 60 ° C. An experiment for measuring heat resistance was conducted.
Table 3 below summarizes the measurement experiment results.

As shown in Table 3, the calculated value of the difference between the biomass plastic moldings in this example does not change even when the outside air temperature changes from room temperature (20 ° C.) to high temperature (60 ° C.). It was also found that it has excellent heat resistance that is the same as that at room temperature.
Moreover, the calculated value of the difference of the biomass plastic molding in the present example shows a value that is substantially equal to or lower than that of Comparative Examples 1 to 5 at both normal temperature and high temperature, In comparison, it was found to have the same or better heat resistance.

Next, water (hot water) of two kinds of temperatures of 15 ° C. and 95 ° C. was injected into the biomass plastic molded product and the bottle-type containers of Comparative Examples 1 to 5 in the above-described Example, and the cap was attached and the lid was closed. In the state, a heat resistance measurement experiment was performed.
Table 4 below summarizes the measurement experiment results.

As shown in Table 4, the calculated difference of the biomass plastic molded product in the present example is almost the same when the water temperature in the molded product is normal temperature (15 ° C) and high temperature (95 ° C). It was also found that it has excellent heat resistance that is the same as that at room temperature even at high temperatures.
Moreover, the calculated value of the difference of the biomass plastic molding in the present example shows a value that is substantially equal to or lower than that of Comparative Examples 1 to 5 at both normal temperature and high temperature, In comparison, it was found to have the same or better heat resistance.

  From the results of the above heat resistance measurement experiments, the biomass plastic molded product in this example has environmentally friendly biodegradability and ease of molding under all temperature conditions, and other fossil fuel-derived resins, etc. It was found to have the same or better heat resistance as the molded product by.

(Example 2)
In Example 1, biomass plastic material was produced by mixing 80% by weight of a mixture of rice starch and polypropylene with 20% by weight of linear low density polyethylene.
In this example, the linear low-density polyethylene to be mixed was reduced to 10% by weight, and polybutylene succinate (PBS) was mixed at 10% by weight to produce a biomass plastic material.
As this polybutylene succinate, PBS biodegradable resin Bionore (manufactured by Showa Polymer) was used.
Other manufacturing conditions were the same as in Example 1.
The biomass plastic material in this example also had excellent strength and heat resistance as in Example 1, and had good moldability for blow molding.
Furthermore, compared with Example 1, since the polybutylene succinate rich in biodegradability was mixed as much as the mixing amount of the linear low density polyethylene was reduced, the biodegradability of the biomass plastic material as a whole is improved. It became possible.

(Example 3)
In this example, an aromatic dicarboxylic acid polyester elastomer excellent in biodegradability was used in place of polybutylene succinate (PBS) in Example 2, and 80% by weight of a mixture of rice starch and polypropylene was directly added. Crosslinking was performed by adding 10% by weight of chain low density polyethylene and 10% by weight of aromatic dicarboxylic acid polyester elastomer to produce a biomass plastic material.
Ecoflex (manufactured by BASF) was used as the aromatic dicarboxylic acid-based polyester elastomer.
Other manufacturing conditions were the same as in Example 1.
The biomass plastic material in this example also had excellent strength and heat resistance as in Examples 1 and 2, and had good moldability for blow molding.
Furthermore, as compared with Example 1, since the aromatic dicarboxylic acid-based polyester elastomer rich in biodegradability was mixed as much as the mixing amount of the linear low-density polyethylene was reduced, the biodegradability of the biomass plastic material as a whole It became possible to improve.

<Summary of Embodiment>
According to the present embodiment, biomass plastic is obtained by adding a crosslinkable polymer that has been subjected to a crosslinking treatment by irradiating an electron beam to a mixture of non-crosslinkable polymers such as rice starch and polypropylene excellent in biodegradability. Since the material is manufactured, it is possible to provide a biomass plastic material excellent in biodegradability, strength resistance, heat resistance, and blow moldability.

  In addition, since the biomass plastic material in the present embodiment is made of rice starch which is relatively easily available as a main material, it can be used for blow molding in consideration of the environment by effectively using the remaining rice as old rice and old used rice. Material can be provided.

In addition, according to the present embodiment, by irradiating an electron beam before forming a biomass plastic molded product, even in a molding factory or the like that does not have an electron beam irradiation facility, the biomass having excellent strength resistance and heat resistance. It becomes possible to mold a plastic molding.
In addition, since there is no need to irradiate the electron beam every time it is molded, the total number of times of electron beam irradiation can be minimized, and the cost of the electron beam emission can be reduced and the biomass plastic molded product can be reduced. It is possible to simplify the manufacturing process.

  In addition, according to the present embodiment, a crosslinkable polymer irradiated with an electron beam is further added to rice starch and a non-crosslinkable polymer, and melted to form a parison, so that the stable shape is less likely to be drawn down by its own weight. It is possible to extrude a so-called “stiff” molten parison. When linear low density polyethylene (LLDPE) is used as the crosslinkable polymer added at this time, a particularly excellent drawdown melted parison is obtained.

  The above-described embodiment is an example of a preferred embodiment of the present invention. The embodiment of the present invention is not limited to this embodiment, and various modifications may be made without departing from the scope of the present invention. Is possible.

According to this embodiment, a mixture of rice starch and a non-crosslinkable polymer is first generated, and a biomass plastic material is generated by adding a crosslinkable polymer subjected to a crosslinking treatment to this mixture. A mixture of starch and a crosslinkable polymer that has undergone a crosslinking treatment may be first produced, and a non-crosslinkable polymer may be added to the mixture.
In addition, rice starch, a non-crosslinkable polymer, and a crosslinkable polymer subjected to a crosslinking treatment may be simultaneously melt-kneaded and then cooled to be formed into pellets or granules.

In the present embodiment, electron beam irradiation is used as a crosslinking method, but the present invention is not limited to this, and crosslinking may be performed by other methods.
For example, as another crosslinking method, an irradiation crosslinking method in which other ionizing radiation such as X-ray, γ-ray, proton beam, deuteron beam, α-ray, and β-ray is irradiated may be used. Also, organic peroxides such as 1,3-bis (tertiarybutylperoxyisopropyl) benzene, 1,1-bis (tertiarybutylperoxy) -3,3,5-trimethylcyclohexane, dicumyl peroxide and the like are used as crosslinking agents. You may make it use the chemical crosslinking method used as these.

In addition, the main material of the biomass plastic material in the present embodiment is rice starch, but the same effect can be obtained as long as it is not biodegradable and derived from non-fossil fuel.
For example, in addition to rice starch, one or a mixture of two or more starches obtained from various plants such as corn starch, potato starch, sweet potato starch, wheat starch, rice starch, tapioca starch and sorghum starch can be used.

It is a side view of the heat resistance test | inspection jig used when measuring the heat resistance of the biomass plastic molding in embodiment of this invention and the other resin material used as a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Heat resistance inspection jig 11 Base board 12 Guide 13 Height adjustment bar 14 Shaft material 15 Load bar 16 Measurement bar 20 Container

Claims (6)

A resin material used for blow molding,
A biomass plastic material produced by melt-kneading rice starch, a non-crosslinkable polymer and a crosslinkable polymer subjected to a crosslinking treatment.   Polypropylene as the non-crosslinkable polymer, linear low density polyethylene as the crosslinkable polymer, 40-80% by weight of rice starch, 10-30% by weight of polypropylene, and linear low density polyethylene subjected to crosslinking treatment The biomass plastic material according to claim 1, wherein the biomass plastic material is produced by mixing 10 to 30% by weight.   The biomass plastic material according to claim 1 or 2, wherein the crosslinking treatment uses an irradiation crosslinking method in which ionizing radiation is irradiated or a chemical crosslinking method in which an organic peroxide is used as a crosslinking agent. A crosslinking step of crosslinking the crosslinkable polymer;
A solid production step of producing a solid after cooling and kneading rice starch, the crosslinkable polymer and the noncrosslinkable polymer subjected to the crosslinking treatment;
A molding step of melt-kneading the solid produced by the solid production step and performing blow molding;
A method for producing a biomass plastic resin molded product, comprising:   The solid production step uses polypropylene as the non-crosslinkable polymer and linear low density polyethylene as the crosslinkable polymer, 40-80% by weight of rice starch, 10-30% by weight of polypropylene, linear low 5. The method for producing a biomass plastic molded product according to claim 4, wherein the density polyethylene is 10 to 30% by weight.   The method for producing a biomass plastic molded product according to claim 4 or 5, wherein in the molding step, the solid material is kneaded, melt-kneaded at 160 to 170 ° C, extruded, and molded.

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