JP2006021502A - Starch-blended resin composition, its manufacturing method, film molded object and method for molding film molded object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique to blend a starch substance with a thermoplastic resin without sophisticated pretreatment and thereby, obtain a starch-blended resin composition in which starch particles are finely and uniformly dispersed, with regard to the technique to blend the starch substance which is a naturally derived substance in order to reduce the consumption of the thermoplastic resin which is a chemically synthesized substance. <P>SOLUTION: The method for manufacturing the starch-blended resin composition comprises the following processes: (A) a raw material charging process to charge a raw material containing the thermoplastic resin and a moistened starch substance into a raw material charging part of a kneading extrusion device regulated to such a low temperature as not allowing evaporation of most of the moisture content; (B) a thermal fluidizing process to gelatinize the starch substance in an atmosphere regulated to high pressure and high temperature; (C) a dispersion process to finely grind/disperse the gelatinized starch by kneading and (D and F) a dehydration process to evaporate the contained moisture. Also, the starch-blended resin composition, the film molded object and the method for molding the film molded object are provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a composition in which a naturally occurring substance is blended with this chemically synthesized substance in order to reduce the amount of the chemically synthesized substance used, and in particular, a method for producing a resin composition in which a starch-based substance is blended, and It relates to the technology related to this.

  Even agricultural products produced for edible use must be discarded if they have passed a suitable period for edible use. In addition, rice is currently oversupplied, so surplus rice held by Japan will continue to increase year by year and will eventually be discarded. In order to effectively use such discarded agricultural products and to reduce the stock of surplus rice, in addition to edible uses, uses of these agricultural products are being sought.

Among these agricultural products, it has been conventionally practiced to obtain a molded product by blending starch-based substances (rice, wheat, corn, potato, sweet potato, tapioca, etc.) with a thermoplastic resin (polyolefin resin, etc.) (for example, Patent Document 1). By blending such a starch-based material, not only the amount of thermoplastic resin produced from fossil fuel is reduced, but also the amount of carbon dioxide generated during incineration is reduced (compared with olefin resin: about 20%). ) Can contribute to the conservation of the global environment.
JP 2004-2613 A

  However, when a starch-based material is blended with a thermoplastic resin, it is difficult to obtain a starch-blended resin composition in which a starch-based material is finely and uniformly mixed in a thermoplastic resin matrix. In particular, when a film molded product is obtained by stretching, if the starch granule powder having a large particle size is unevenly distributed, the film thickness becomes non-uniform or cracks occur during the stretching process. As a result, there is a problem in that deterioration of various properties is unavoidable, for example, there is a limit to thinning the film, and mechanical properties, appearance, and texture of the film after molding are extremely inferior.

  Conventionally, in order to deal with such problems, after performing advanced pretreatment such as finely pulverizing starch-based materials or extracting only starch components, they are blended into thermoplastic resins and heat-fluidized. The starch-containing resin composition was obtained by kneading at a temperature. However, the starch-containing resin composition obtained by such a conventional method has a problem in terms of cost because of the pretreatment process described above. Further, the degree of refinement of the starch granules dispersed in the starch-blended resin composition is almost determined by the particle size achieved by the above-mentioned pulverization, and there is a limit to reducing the particle size. By the way, in the film molded product, the particle size of the starch granules to be dispersed is required to be equal to or less than the film thickness. For this reason, there has been a technical problem that the starch grains must be reduced in size to the extent appropriate for the film thickness in response to the request for thin film formation (thickness of about several tens of μm).

  The present invention solves the above problems, and a starch-containing resin composition in which a starch-based material is blended in a thermoplastic resin without performing advanced pretreatment, and the starch granules are finely and uniformly dispersed. It is made for the purpose of providing the manufacturing method of this, and the technique relevant to this.

  The present invention was devised to solve the above-described problems and achieve the above-described object. First, the first invention is a raw material charging step as described in claims 1 and 4. In (A), water, starch-based material, and thermoplastic resin are charged into the raw material charging part, but since this raw material charging part is adjusted to a low temperature of 140 ° C. or lower, Most do not evaporate immediately. Next, in the heat fluidization treatment step (B), the water, starch-based material, and thermoplastic resin that have been charged are exposed to a high temperature (higher than the adjustment temperature of the raw material charging portion and the upper limit is about 200 ° C.). The whole fluidizes. However, since the atmosphere is higher than atmospheric pressure, water does not vaporize even at a high temperature of 100 ° C. or higher. For this reason, gelatinization progresses in a shorter time for the starch substance of the starch-based substance containing high-temperature water.

  Next, in the dispersion treatment step (C), when the gelatinized starch and the heat-flowable thermoplastic resin are kneaded, the gelatinized starch becomes finely crushed starch granules and uniformly in the matrix of the thermoplastic resin. Will be distributed. Thus, gelatinized starch is easily refined because its molecular structure has an amorphous structure, and thus has a property of being easily scattered at the molecular chain level. Next, in the dehydration treatment step (D), water that has been added together with the starch-based material and the thermoplastic resin and contributed to the gelatinization of the starch-based material is discharged after finishing its role. This is because moisture is originally an unnecessary component for the starch-containing resin composition that is the final product. This discharge of water is automatically performed only by changing the high-pressure atmosphere, which was higher than the atmospheric pressure in the dispersion treatment step (C) in the previous step, to the atmospheric pressure in the dehydration treatment step (D). Furthermore, if the forced disposal device is used to change the atmosphere to a low-pressure atmosphere below atmospheric pressure, a high dehydration effect is exhibited. Furthermore, the starch-containing resin composition obtained through the discharging step (G) and the molding step (I) has a structure in which starch granules dispersed therein are refined and more uniformly distributed.

  Further, according to the second invention, as described in the second to tenth aspects, in the atomization step (H), the heat of the thermoplastic resin in which starch particles of a certain size or gelatinized starch is already dispersed is obtained. When the fluid passes through the gap between the heat rolls, further refinement of the starch granules and the like is achieved.

The starch-containing resin composition, the production method thereof, the film molded product thereof, and the molding method of this molded product according to the present invention have the following excellent effects.
That is, it is possible to obtain a starch-containing resin composition in which a starch-based substance is blended into a thermoplastic resin without performing advanced pretreatment, and the starch granules are finely and uniformly dispersed. For this reason, if this starch-blended resin composition is used, a film molded product having low costs and excellent properties can be obtained.
Furthermore, since a starch-containing resin composition and a film molded product thereof with an increased ratio of starch-based materials to be blended can be obtained, it is manufactured from fossil fuels using a large amount of starch-based materials (for example, surplus rice) that are difficult to dispose of. It is possible to reduce the amount of thermoplastic resin used. Furthermore, the amount of combustion heat and carbon dioxide generated can be suppressed even after incineration, and by using a biodegradable thermoplastic resin, it will be decomposed 100% even when landfilled. Contributes greatly to conservation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an overall perspective view showing a granulation apparatus for producing a starch-containing resin composition (pellet) according to this embodiment.
The granulating apparatus 10 includes a twin-screw kneading and extruding apparatus 20 that heat-fluidizes and kneads a thermoplastic resin that is a raw material of the starch-blended resin composition and a hydrous-treated starch-based material, and a drive required for this kneading. A drive unit 22 for applying a force to the biaxial kneading and extruding device 20, a heat roll 40 for further refinement of starch granules contained by passing the thermal fluid that has been kneaded and extruded from the discharge port 28, and the heat roll The side hot-cut device 50 is formed by chopping and solidifying the thermal fluid passing through 40 into pellets 51, 51.

The biaxial kneading extruder 20 will be described with reference to FIG. Here, Fig.2 (a) shows the side sectional drawing of the biaxial kneading extrusion apparatus 20, (b) shows a horizontal sectional view.
The biaxial kneading and extruding apparatus 20 has an outer peripheral portion constituted by a hollow cylinder 21, and two screws 30 that rotate in mesh with each other in the same direction by the driving force of the driving portion 22 inside the hollow of the cylinder 21. 30 is arranged. A hopper 23 for charging the raw material is provided in the uppermost stream of the biaxial kneading and extruding apparatus 20 where the drive unit 22 is disposed. Further, above the opening of the hopper 23, a feed pot 23a for feeding the raw material thermoplastic resin into the hopper 23 and the raw water-treated rice (starch-based material) are also fed into the hopper 23. An infeed pot 23b is arranged.

Here, the raw material thermoplastic resin accumulated in the feeding pot 23a forms a matrix of the starch-containing resin composition, and is composed of low density polyethylene (HPPE), high density polyethylene (HDPE), polypropylene ( Polypropylene resins such as PP), ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA) and the like are typical examples, but other than these, polycarbonate resin (PC), polyethylene terephthalate resin (PET), acrylic / butylene / styrene (ABS), and the like may also be used, and any resin can be used without particular limitation as long as it has a property of being thermally fluidized by heating. Moreover, you may use these thermoplastic resins in mixture of 2 or more types.
On the other hand, if a thermoplastic resin having biodegradability such as polylactic acid (PLA), polybutylene succinate (PBS), polycaptolactone (PCL) is used, all of them are reduced to soil. And a suitable starch-containing resin composition from the viewpoint of environmental protection. Similarly, from the viewpoint of environmental conservation, polyolefin resins to which additives that impart biodegradability such as Tegranobon (trademark) and ECM Masterbatch (trade name) of Macrotech Research (USA) are added. To preferred.

In addition, the “moisture-treated rice” accumulated in the feeding pot 23b is specifically processed by immersing raw rice in water for a predetermined time and draining it with a centrifuge. Is. The raw rice used here may be in the form of brown rice or polished rice, and there is no need for any special treatment such as pulverization or heat treatment in advance. In addition, it is possible to use old and cheap rice and waste rice at low prices.
As starch-based substances that can be used, wheat, corn, potato, sweet potato, tapioca and the like can be used in addition to the rice listed here. Even when these substances other than rice are used, they can be used by a simple treatment that removes the core and the skin.

  Then, the thermoplastic resin and the starch-based material are fed into the hopper 23 from the feeding pot 23a and the feeding pot 23b, respectively, so as to have a predetermined blending ratio. The blending ratio of the starch-based material is 80 parts by weight and the lower limit is 5 parts by weight with respect to 100 parts by weight of the total amount of the thermoplastic resin and the starch-based material. The upper limit of 80 parts by weight is that when the amount of the starch-based material is further increased, the starch-containing resin composition matrix is formed with the starch-based material, This is because the desired texture as a film cannot be obtained. The lower limit of 5 parts by weight is because below this, the desired heat generation suppression effect cannot be obtained during incineration.

  In some cases, the hopper 23 may be further fed with a compatibilizing agent that improves the compatibility with the thermoplastic resin and the starch-based material. As this compatibilizer, for example, a saturated carboxylic acid, an unsaturated carboxylic acid, or a derivative thereof is used. Specific examples of the saturated carboxylic acid include succinic anhydride, succinic acid, phthalic anhydride, phthalic acid, tetrahydrophthalic anhydride, and adipic anhydride. Examples of the unsaturated carboxylic acid include maleic acid, maleic anhydride, nadic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, sorbic acid, acrylic acid and the like. As the derivative of the unsaturated carboxylic acid, a metal salt, amide, imide, ester or the like of the unsaturated carboxylic acid can be used. Further, a polyolefin resin modified with an unsaturated carboxylic acid or a derivative thereof can be used. This can be obtained by heating and mixing a polyolefin, an unsaturated carboxylic acid or derivative thereof, and a radical generator in the presence or absence of a solvent. An appropriate blending amount of the compatibilizing agent is obtained experimentally, but may be in the range of 0.2 to 20 parts by weight with respect to 100 parts by weight of the total amount of the thermoplastic resin and the starch-based substance. desirable.

Returning to FIG. 1 and FIG. 2, the description will be continued.
As shown in FIG. 1, in order to obtain a starch-containing resin composition (pellets 51, 51...) Using a granulator 10, a raw material charging process A, a thermal fluidization process B, a dispersion process C, It is necessary to go through a plurality of steps represented by processing steps D and F, chemical reaction step E, discharge step G, atomization step H, and molding step I in order. Of these steps, A to F are executed in a plurality of sections provided at predetermined intervals in the longitudinal direction of the biaxial kneading and extruding apparatus 20, as shown in FIG.

Here, in the raw material charging step A, a raw material (thermoplastic resin, water-treated rice) of the starch-blended resin composition is fed from a hopper 23 to a section of the biaxial kneading extruder 20 indicated by the raw material charging section (low temperature section) a. (Starch-based substance), a mixture of compatibilizers, and the like). These raw materials are transferred to the temperature raising part b1 adjacent to the downstream side by the flights 31 spirally provided on the surfaces of the kneading screws 30, 30 rotating in the same direction at a predetermined interval. By the way, since this raw material charging part (low temperature part) a is adjusted to a low temperature at which the temperature T ₁ is 140 ° C. or lower (preferably 100 ° C. or lower), the water contained in the input rice is supplied to the raw material charging step A Most of it does not evaporate immediately.

Next, the thermal fluidization process B is further classified into a temperature raising process B1 and a gelatinization process B2. Here, the temperature raising step B1 includes raw materials (thermoplastic resin, water-treated rice (starch-based material), compatibilizing agent) from upstream to downstream of a section of the twin-screw kneading extruder 20 indicated by the temperature raising part b1. And the like, while increasing the temperature T ₁ to the heat flow temperature T ₂ (preferably 120 ° C. to 200 ° C.) at which the thermoplastic resin flows.
In the following, in order to indicate the temperature of each section (af) of the twin-screw kneading and extruding apparatus 20, the description of “thermal flow temperature T ₂ ” appears, but this is simply the temperature at which the raw material is thermally fluidized. only it indicates that is, thermal flow temperature T _2, shown as the temperature is not all the same temperature in each compartment (a to f). Of course, the set temperature in each compartment (af) should be selected such that each process is optimized.

And gelatinization process B2 is the process of gelatinizing the rice thrown in as a raw material in one division of the twin-screw kneading extrusion apparatus 20 shown as high temperature high pressure part (weak kneading part) b2. The high-temperature high-pressure part (weakly kneaded part) b2 is uniformly held at the heat flow temperature T ₂ from the upstream side to the downstream side. Further, the pitch of the flights 32, 32... Provided in a spiral shape on the surface of the corresponding kneading screws 30, 30 is set narrower than the pitch of the upstream flights 31, 31. As a result, in the high-temperature and high-pressure part b2, the raw material is kneaded weakly because the pitch is narrowed and the occupied space is narrowed, and further the heat flow as a whole. Moreover, the inner surface of the cylinder 21 in the high-temperature and high-pressure part b2 completely shuts out the outside air, and the upstream and downstream sides are both sealed with raw materials, so the inside of the high-temperature and high-pressure part b2 is sealed. Even if there is, an atmosphere higher than atmospheric pressure is formed. In the high-temperature and high-pressure part b2, the water exposed to such a high-pressure atmosphere can exist in a liquid state without being vaporized even at a high temperature. And the rice impregnated with water having such a high heat flow temperature T ₂ is gelatinized in a short time.

Here, the gelatinization of rice means the following phenomenon (the same explanation applies to starch-based substances in general).
Normally, raw rice itself has a water content of about 13% by weight. However, if the water content is further increased and placed in a temperature environment of 70 ° C. or higher, the initial content of starch constituting the raw rice is as follows. The crystal structure (β structure) breaks down and has an amorphous structure (α structure). Thus, when starch contains moisture and changes from the β structure to the α structure, the raw rice changes from a hard state to a paste-like gel state. This phenomenon is called gelatinization. In addition, it is known that this gelatinization reaction will progress faster, so that there is much water | moisture content contained in starch, and it is high temperature.

Inside the high-temperature and high-pressure part b2, water is present in a large amount as a liquid even at a high temperature of the heat flow temperature T ₂ (usually 120 to 200 ° C.). It can be transferred to the structure in a short time. In this gelatinization step B2, the raw material is thermally fluidized by containing a large amount of water under a high temperature and high pressure atmosphere to form a hydrous thermal fluid P. The raw rice contained in the hydrous heat fluid P can be gelatinized in a short time during the kneading process.

Next, in the dispersion treatment step C, the gelatinized rice (gelatinized starch) contained in the hydrous heat fluid P is crushed and dispersed in one section of the biaxial kneading and extruding apparatus 20 shown as the first toughening part c. It is a process to make. The first strength portion c is uniformly held at the heat flow temperature T ₂ from upstream to downstream. A plurality of paddles 33, 33... Are provided in corresponding portions of the kneading screws 30, 30. 3A is an enlarged top view showing a stack of paddles 33, 33... Provided in the kneading screws 30, 30, and FIG. 3B is a view as seen from the direction perpendicular to the axis of the cylinder 21. As shown in FIG. It is.

The configuration and operation of the paddles 33, 33.
These paddles 33, 33... Are fixed so that the phases of rotation of the adjacent kneading screws 30, 30 are shifted from each other by 90 °, and are further shifted by 45 ° sequentially in the longitudinal direction of the kneading screws 30, 30. It is fixed. FIG. 4 is a diagram illustrating the operation of a pair of paddles 33, 33... Attached to adjacent kneading screws 30, 30. FIGS. 4 (a) to (e) show that the kneading screws 30, 30 are 45 degrees each. The state when rotating in the same direction is shown.

  As is clear from FIG. 4, the kneaded material in the regions represented by A, B, and C is strongly kneaded (strengthened) around the inner periphery of the cylinder 21 as the kneading screws 30 and 30 rotate. I understand that Here, returning to the manufacturing process of the starch-containing resin composition, the explanation will be continued. When the rice is gelatinized and transferred to the first hardened portion c in the high-temperature and high-pressure portion b2, gelatinized rice (gelatinized starch) ) Shows a gel state, and when it is tempered, the molecular chain of the starch is loosened, and the starch grains are refined at the molecular level and dispersed in the matrix of the thermoplastic resin (starch content). Heat dissipation fluid Q). Since the internal pressure of the first hardened portion c is maintained at a pressure higher than the atmospheric pressure, the remainder of the rice that could not be gelatinized at the high-temperature high-pressure portion b2 is all gelatinized here and similarly fined. Will be dispersed. Up to this point, it is impossible to refine and disperse the starch granules, as described in the prior art, no matter how finely the starch-based material is pulverized when the starch structure is a β structure (crystal structure). .

Next, the dehydration process D is a process in which water is removed from the starch-dispersed thermal fluid Q to make the anhydrous thermal fluid R in one section of the twin-screw kneading extruder 20 shown as the first degassing part d. The first degassing part d is kept uniform by the heat flow temperature T _2. And the open vents 25 and 25 opened to air | atmosphere are provided in the upper surface part of the cylinder 21 of this 1st deaeration part d. Due to the presence of the open vents 25, 25, the internal pressure of the first degassing part d becomes an atmospheric pressure level, and the starch-dispersed thermal fluid Q that has been transferred from the upstream first strengthening part c. Will be exposed to a sudden drop in pressure. For this reason, the water | moisture content contained in a raw material is vaporized at a stretch, is discharged | emitted outside from the open vents 25 and 25, and the anhydrous heat fluid R is formed.

Next, in the chemical reaction step E, in one section of the biaxial kneading and extruding apparatus 20 shown as the second toughening part e, the compatibilizer charged as a raw material is chemically changed to change the thermoplastic resin and gelatinized starch, It is the process of improving the affinity of and improving dispersity. This second toughened portion e is maintained at the heat flow temperature T ₂ , and the anhydrous heat fluid R passing therethrough is kneaded (strengthened) strongly again, so that the starch granules of the gelatinized starch become finer. In addition, the added compatibilizing agent chemically reacts to increase the affinity between the refined starch granules and the thermoplastic resin, thereby further increasing the degree of dispersion.

  Next, the dehydration process F is a process of further removing moisture remaining in the anhydrous heat fluid R by the forced exhaust device 27 in one section of the twin-screw kneading extruder 20 shown as the second degassing part f. A vacuum vent 26 that opens to the atmosphere is provided on the upper surface of the cylinder 21 of the second degassing part f, and a forced exhaust device 27 is provided there. When the forced exhaust device 27 is driven, the internal pressure becomes equal to or lower than the atmospheric pressure, and the remaining water that cannot be completely discharged in the dehydration process D is discharged from the anhydrous thermal fluid R.

Next, in the discharge process G, the anhydrous thermal fluid R is discharged from the discharge port 28 in which the diameter of the most downstream end of the cylinder 21 is narrowed.
Then, in the atomization step H, the discharged anhydrous heat fluid R passes through the heat roll 40, whereby the starch particles are further refined. The pair of rolls 41 and 41 are arranged so that their longitudinal central axes are parallel to each other, and rotate about the central axis. The gap 42 formed by the pair of cylindrical rolls 41 and 41 is appropriately adjusted according to the target starch particle size. Further, the direction and speed of rotation of the rolls 41 and 41 are experimentally determined so that the effect of refining starch granules can be maximized. Furthermore, the pair of rolls 41, 41 so as to maintain the temperature of the surface heat flow temperature T _2, as a whole is accommodated in the heating furnace 43.
In addition, in FIG. 1, although the heat roll 40 was comprised from a pair of rolls 41 and 41, it is not limited to such a structure, For example, one rotating roll and a plane plate It may be constituted by. That is, the heat roll 40 means that the anhydrous thermal fluid R is passed through the gap 42 formed by the circumferential surface of one rotating roll 41 and the surface of another object, and the contained starch granules are It is further refined by crushing with or by breaking with shearing force.

Next, the molding step I can take various embodiments. In FIG. 1, pellets 51, 51... Are granulated as a starch-containing resin composition using a commonly used side hot cut device 50. The process is shown. In FIG. 1, after passing through the heat roll 40, shredding is performed by the side hot cut device 50, but without passing through the heat roll 40, the discharge port 28 of the biaxial kneading extrusion device 20 is used. In some cases, the anhydrous heat fluid R is directly guided to perform shredding.
FIG. 5 shows another embodiment of the molding process, and shows a process of obtaining a cylindrical thin film film molded article using the inflation molding apparatus 60. In FIG. 5, the same components as those described above are denoted by the same reference numerals and description thereof is omitted.

Inflation molding means that the raw material is kneaded by a biaxial kneading and extruding apparatus 20 equipped with a die having an annular die (die) 61 (kneading step J), and the heat fluid is extruded into a cylindrical shape (discharge step G). After air S is blown into the film to be stretched (stretching process K), it is cooled by the cooling ring 66 to form a thin cylindrical film (molding process I), which is guided by the stabilizer 65 and pinched roll 64. This is a method in which the inside air is removed and the winding device 62 winds it through the guide roll 63.
According to this inflation molding, since a resin thin film is formed by biaxial stretching, mechanical properties such as tensile strength and impact resistance are excellent. Further, since the inflation molding is formed as a continuous cylindrical film molded product, it is widely used for the production of wraps and bags of thermoplastic resins such as polyethylene and polypropylene.

  According to the method for producing a film-shaped article of a starch-based resin composition according to the present invention, even if air S is rapidly inflated by putting air S inside the heat-fluidized resin, the starch granules are finely and uniformly dispersed. In addition, since there is no granular defect portion formed by aggregation of the starch grains, the film is stretched with a uniform and uniform film thickness. For this reason, after cooling, the obtained film molded product has a uniform film thickness, looks beautiful as if it was molded with 100% polyolefin resin, and even if the degree of stretching is increased, there are no defects such as cracks and pinholes. The mechanical properties (such as tensile strength) are also excellent.

  As described above, in the description of FIG. 5, it is assumed that the biaxial kneading / extrusion apparatus 20 described in detail in FIG. 2 and the like is used. Predetermined characteristics of the above-mentioned film molded product can be brought out by the presence of. Moreover, even if it is the inflation molding apparatus 60 equipped with general purpose kneading extrusion apparatus 20 ', if the pellets 51, 51 ... granulated by the granulation apparatus 10 of FIG. A film molded product can be obtained.

It is a whole perspective view which shows the granulation apparatus for manufacturing the starch compounding resin composition (pellet) concerning this embodiment. (A) shows the side sectional view of the biaxial kneading extrusion device used in this embodiment, and (b) shows the horizontal sectional view. (A) is the top view which expands and shows the laminated body of the paddle provided in the kneading screw, (b) is the figure seen from the axial direction of the cylinder. It is a figure which shows operation | movement of a pair of paddle attached to the adjacent kneading screw, Comprising: (a)-(e) shows a state when each kneading screw rotates in the same direction 45 degrees. It is a front view of the inflation molding apparatus which manufactures the film molded product concerning this embodiment.

Explanation of symbols

20 Biaxial kneading extrusion equipment (kneading extrusion equipment)
28 Discharge port 30 Kneading screw 40 Heat roll 42 Gap 60 Inflation molding device A Raw material input process B Thermal fluidization process B1 Temperature rising process B2 Gelatinization process C Dispersion process D, F Dehydration process E Chemical reaction process G Discharge process H Atomization process I Molding process J Kneading process K Drawing process P Hydrous heat fluid Q Starch dispersion heat fluid R Anhydrous heat fluid

Claims (10)

In the method for producing a starch-containing resin composition comprising a thermoplastic resin and a starch-based material as main raw materials,
Raw material input of a kneading and extruding apparatus in which a raw material containing at least 100 parts by weight of 20 to 95 parts by weight of the thermoplastic resin and 80 to 5 parts by weight of the hydrous-treated starch-based material is adjusted to a temperature of 140 ° C. or lower. Raw material input process to be input to the department,
The charged raw material is conveyed to a high-temperature and high-pressure part adjusted to a high temperature at which the pressure is higher than atmospheric pressure and the thermoplastic resin is heat-flowed to become a hydrous heat fluid, and at least one of the starch-based substances contained therein. A heat fluidization process in which the part is gelatinized to become gelatinized starch;
The hydrothermal fluid is kneaded under the same high temperature and high pressure, the remainder of the starch-based material is gelatinized, and the resulting gelatinized starch is crushed into starch granules, and the starch granules become the hydrothermal fluid A dispersion treatment step to be dispersed in the whole body to become a starch-dispersed thermal fluid,
The starch-dispersed thermal fluid is conveyed to a deaeration section adjusted to a low pressure below atmospheric pressure and a high temperature at which the starch-dispersed thermal fluid is thermally fluidized, and moisture contained in the starch-dispersed thermal fluid is evaporated. A dehydration process to become an anhydrous heat fluid,
A discharge step of discharging the anhydrous thermal fluid from the discharge port of the kneading extruder;
A method for producing a starch-containing resin composition, comprising: a molding step in which the discharged anhydrous thermal fluid solidifies into a starch-containing resin composition under a low temperature at which thermal fluidity is lost. In the manufacturing method of the starch compounding resin composition of Claim 1,
Starch characterized in that it further includes a atomization step in which the anhydrous heat fluid passes through a gap between heat rolls to make the starch particles finer after the discharging step and before the molding step. A method for producing a compounded resin composition. In the method for producing a starch-containing resin composition comprising a thermoplastic resin and a starch-based material as main raw materials,
A kneading step in which the raw material charged into a kneading and extruding apparatus is kneaded at a temperature at which the thermoplastic resin is thermally fluidized, and the starch-based substance contained or starch granules formed by pulverization thereof are dispersed;
A discharge step of discharging the kneaded thermal fluid from the discharge port of the kneading extruder;
The discharged thermal fluid passes through the gap of the heat roll, and the starch-based material to be dispersed, or the atomization step for further refinement of the starch granules,
The method for producing a starch-containing resin composition, characterized in that the thermal fluid that has undergone the atomization step includes a molding step that becomes a starch-containing resin composition by solidifying under a low temperature at which heat-fluidity is lost. . In the manufacturing method of the starch compounding resin composition of Claim 3,
The kneading step includes
Raw material input of a kneading and extruding apparatus in which a raw material containing at least 100 parts by weight of 20 to 95 parts by weight of the thermoplastic resin and 80 to 5 parts by weight of the hydrous-treated starch-based material is adjusted to a temperature of 140 ° C. or lower. Raw material input process to be input to the department,
The charged raw material is conveyed to a high-temperature and high-pressure part adjusted to a high temperature that is higher than atmospheric pressure and the thermoplastic resin is heat-fluidized, becomes a hydrous thermal fluid, and contains at least the starch-based substance contained A heat fluidization treatment process in which a part is gelatinized into gelatinized starch,
The hydrothermal fluid is kneaded under the same high temperature and high pressure, the remainder of the starch-based material is gelatinized, and the resulting gelatinized starch is crushed into starch granules, and the starch granules become the hydrothermal fluid A dispersion treatment step to be dispersed in the whole body to become a starch-dispersed thermal fluid,
The starch-dispersed thermal fluid is conveyed to a deaeration section adjusted to a low pressure below atmospheric pressure and a high temperature at which the starch-dispersed thermal fluid is thermally fluidized, and moisture contained in the starch-dispersed thermal fluid is evaporated. And a dehydration treatment step for forming the anhydrous thermal fluid R, and a method for producing a starch-containing resin composition. In the manufacturing method of the starch compounding resin composition in any one of Claims 1-4,
The method for producing a starch-containing resin composition, wherein the starch-based substance is composed of at least one substance selected from the group of substances of rice, wheat, corn, potato, sweet potato, and tapioca. In the manufacturing method of the starch compounding resin composition of any one of Claims 1-5,
The thermoplastic resin is composed of at least one compound selected from a compound group of polyolefin resin, polylactic acid, polybutylene succinate, and polycaptolactone imparted with biodegradability. A method for producing a resin composition.   The starch compounded resin composition obtained by the manufacturing method of the starch compounded resin composition of any one of Claims 1-6.   A film-molded product obtained by heating and heat-fluidizing the starch-containing resin composition according to claim 7 and then stretching and molding. In the manufacturing method of the starch-containing resin composition according to any one of claims 1 to 4,
A method for producing a film molded article, further comprising a stretching step of stretching the anhydrous thermal fluid discharged in the discharging step into a film shape. A step of heat-kneading a starch-containing resin composition containing a thermoplastic resin and a starch-based material as main raw materials to form a thermal fluid;
Passing the thermal fluid through the gap between the heat rolls to refine the starch grains of the starch-based material;
A method for producing a film molded product comprising the step of drawing the thermal fluid that has passed through the gap between the heat rolls into a film shape.

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