JP2020063430A - Resin composite material - Google Patents

Abstract

To provide a resin composite material that has sufficient interfacial adhesion between a continuous phase of a synthetic resin and a dispersion phase of a filler and has excellent properties.SOLUTION: A resin composite material at least has a continuous phase of a synthetic resin, a nanosheet that comprises phyllosilicate peeled as a single layer and has a surface not chemically modified, and a dispersion phase of a filler that is crosslinked via the nanosheet to a molecular chain of the synthetic resin.SELECTED DRAWING: Figure 3

Description

  TECHNICAL FIELD The present invention relates to a resin composite material in which a filler is dispersed in a synthetic resin.

  By dispersing and compounding a filler in a synthetic resin, the amount of synthetic resin produced from fossil resources is reduced, and development of a resin composite material that exhibits new functions is under way.

  As a technique for forming a dispersed phase of the filler finely and uniformly with respect to the continuous phase of the synthetic resin, water (liquid medium) is added to the synthetic resin and the filler, and the mixture is kneaded at a melting temperature of the synthetic resin or higher in a closed container, A technique of manufacturing a composite material by opening to the atmosphere and evaporating and dehydrating is disclosed (for example, Patent Document 1). Further, there is disclosed a technique for producing a composite material by kneading a synthetic resin and a filler while introducing high-pressure steam and vaporizing and dehydrating a condensate of the high-pressure steam (for example, Patent Document 2).

Japanese Patent No. 4660528 Japanese Patent No. 5951146

  However, in the technique disclosed in Patent Document 1, there is a problem that it is not appropriate from the viewpoint of production efficiency to knead a liquid medium having a large heat capacity while raising the temperature from room temperature to the melting temperature of the synthetic resin or higher.

  Further, in the technique disclosed in Patent Document 2, it is difficult to add a large amount of fine powder that easily scatters, such as fly ash, as a filler, and there is a problem that there is little room for improving the physical properties of the resin composite material. . Further, in these prior arts, there is a problem that the interfacial adhesion between the synthetic resin and the filler is insufficient, while the dispersibility of the filler is effective.

  The present invention has been made in consideration of such circumstances, and an object thereof is to provide a resin composite material having sufficient interfacial adhesion between a continuous phase of a synthetic resin and a dispersed phase of a filler and excellent in various physical properties. And

  In the resin composite material according to the present invention, a continuous phase of a synthetic resin, a monolayer exfoliated layered silicate nanosheet having a surface which is not chemically modified, and the synthetic resin forming a bridge between the nanosheets. And a dispersed phase of the filler bonded to the molecular chain of (1).

  According to the present invention, the interfacial adhesion between the continuous phase of the synthetic resin and the dispersed phase of the filler is sufficient, and a resin composite material having excellent physical properties is provided.

4 is a flowchart regarding determination of the compounding of the resin composite material according to the embodiment. A table summarizing the effects of fillers on the physical properties of resin composites for inorganic powders and starch-based substances. The table which summarized the physical property which the resin composite material which concerns on an Example and a comparative example shows. 6 is a table showing the occurrence status of good and defective when the resin composite materials according to Examples and Comparative Examples are film-formed. The table which shows the test result regarding the film-forming property in inflation molding of the resin composite material which has PBAT in a continuous phase, and productivity. The table which shows the test result which evaluated the biodegradation rate of the resin composite material.

  Embodiments of the present invention will be described below. The method for producing a resin composite material according to the present embodiment includes a step of gelling a clay mineral-based material mixed with a liquid medium, and mixing the gel-like clay mineral-based material and a synthetic resin into a first mixture. And a step of mixing the first mixture and a filler into a second mixture, and charging and kneading the second mixture into a pressure vessel set to a temperature at which the synthetic resin melts and kneading. And a step of adjusting the pressure valve of the pressure vessel to vaporize and discharge the liquid medium to adjust the liquid medium content rate in the kneaded material, and the kneaded material with the water content adjusted Removing from the pressure vessel.

  Examples of the clay mineral-based material include those containing a layered silicate, and bentonite containing montmorillonite as a main component is preferably used. The gel-like clay mineral-based material is obtained mainly by adding water as a liquid medium, but other hydrophilic liquid medium or hydrophobic liquid medium such as mineral petroleum may be added. By using a hydrophobic liquid medium instead of a hydrophilic liquid medium such as water, the viscosity of the gel is reduced and the workability when mixing synthetic resins and fillers is improved, or synthetic resins and fillers are used. Depending on the combination of the two, the interfacial adhesion between the two may be improved.

  When the layered silicate swells in a liquid medium and gels, the layered silicate separates into a single layer and becomes a nano-sized sheet. When the gel-like layered silicate and the pellet-shaped synthetic resin are mixed, the viscosity of the gel-like layered silicate causes the first mixture in which the layered silicate is spread on the surface of the pellet-shaped synthetic resin. Become. The clay mineral-based material applied in the embodiment is not limited to the layered silicate, and when it is made into a gel in the presence of water, it exfoliates into a single layer and becomes a nano-sized sheet. If so, it is appropriately adopted.

  Then, in the second mixture obtained by blending and mixing the filler with the first mixture, excess water (liquid medium) in the first mixture is supplied to the filler. Furthermore, when the second mixture is kneaded at the melting temperature of the synthetic resin, the filler is evenly dispersed in the synthetic resin melt by the action of excess water. Then, when excess water contained in the kneaded product of the second mixture is vaporized and discharged, a resin composite material in which a fine filler is uniformly dispersed in the continuous phase of the synthetic resin is formed. At this time, the layered silicate nanosheet bridges the molecular chain of the synthetic resin and the filler in a bridging manner to improve the interfacial adhesion between the synthetic resin and the filler.

As the filler, a powder whose particle size is defined as 100 μm or less while maintaining a solid state without melting at the kneading temperature, or a substance whose specific surface area is defined as 10,000 cm ² / g or more can be used. Specific examples thereof include calcium carbonate obtained by crushing limestone, talc obtained by crushing layered minerals, and inorganic powder such as fly ash generated from a coal-fired power plant and the like. Alternatively, in addition to such powders, bulky substances such as fibrous or cotton-like substances may be used to densely fill these. In addition to inorganic substances, it can be applied to various organic compounds such as crushed FRP products and recycled plastic products. Then, the compounding amount of the filler is 1 part by weight or more with respect to 100 parts by weight of the synthetic resin.

  By the way, in the resin composite material manufactured by the above-mentioned process, excess water (liquid medium) may be retained as interlayer water of the layered silicate. For this reason, a molding defect may occur in a molded product molded using the resin composite material containing excess water. Therefore, in the process of kneading the kneaded product in the pressure vessel, the opening of the pressure valve is adjusted to vaporize the water and discharge it into the atmosphere to adjust the water content (liquid medium content) in the kneaded material. When the resin composite material is molded into a thin film, it is preferable to manufacture the resin composite material so that the water content is 0.3% or less, but in the other moldings, the water content may be 1% or less. Good.

  The wide availability of the resin composite material in which the above-mentioned filler is dispersed makes it possible to effectively utilize, as a filler, low / unused resources that are generated in large quantities every year in coal-fired power generation and the like. When coal is burned in a boiler in a coal-fired power plant or the like, a large amount of coal ash corresponding to 10% of the coal ash is generated as the coal burns.

In fly ash, particles of molten coal ash are suspended in high-temperature combustion gas and cooled at a boiler outlet at a constant temperature to form glass-like spherical particles, which are collected by a dust collector or the like. Silica (SiO ₂ ) and alumina (Al ₂ O ₃ ) account for 70 to 80% as the main component of fly ash, and other components include iron oxide (Fe ₂ O ₃ ), calcium oxide (CaO), and magnesium oxide. (MgO), sodium oxide (Na ₂ O), potassium oxide (K ₂ O) and the like.

  Until now, fly ash has been used for landfill applications, admixtures for concrete, etc., but for landfill applications, the use of fly ash is avoided because the liquefaction phenomenon that occurred during the earthquake often occurred at landfill sites due to fly ash. As a result, the demand for use as a concrete admixture has peaked out and there is no prospect of future expansion. Also, in China and other countries, there are some efforts to extract aluminum, but it is not practical in terms of cost and quality.

  Under such circumstances, efforts are being made to use fly ash as a filler for resin composite materials, but since fly ash is spherical particles, it has poor interfacial adhesion with synthetic resin and its use is limited. was there. However, in the present embodiment, the nanosheet exfoliated from the layered silicate bridge-bonds the molecular chain of the synthetic resin and the fly ash, thereby improving the adhesiveness of the interface and improving various physical properties. . In particular, layered silicate nanosheets composed of a silica layer and an alumina layer and fly ash show high compatibility, and thus a dramatic improvement in various physical properties is recognized.

  Further, since fly ash is spherical particles, it has high heat fluidity when melt-kneaded with a synthetic resin. Further, fly ash can be molded into a molded product even if it is a resin composite material having a higher filling rate than other inorganic powders. Therefore, by increasing the filling rate of fly ash in the resin composite material, it is possible to reduce the amount of synthetic resin used and save fossil resources.

  The synthetic resin forms the continuous phase of the resin composite material, and may be either a thermoplastic resin that melts by heating or a thermosetting resin that cures by heating. As the thermoplastic resin, a polyolefin resin such as low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP) or the like, which is molded into pellets, polycarbonate resin (PC), polyethylene terephthalate resin (PET). , Acrylic butylene styrene (ABS), polyvinyl chloride (PVC), polystyrene (PS), polyamide (PA), and polybutylene adipate-butylene that is decomposed into water and carbon dioxide by the force of microorganisms in the soil Any biodegradable plastic, such as terephthalate copolymer (PBAT), which has the property of being heat-fluidized by heating and which can be generally extruded, can be used without particular limitation. Further, these thermoplastic resins may be used as a mixture of two or more kinds. Further, a recycled product of this thermoplastic resin can also be used.

  Of these, when a polybutylene adipate-butylene terephthalate copolymer (hereinafter referred to as PBAT) is adopted as the synthetic resin of the embodiment, a resin composite suitable as a molding raw material for agricultural materials buried in soil or materials for container packaging. Material is provided. That is, it is possible to realize a resin composite material that is inexpensive, has excellent moldability, and has biodegradability while satisfying the toughness required for a product.

  PBAT is a copolyester of adipic acid, 1,4-butanediol and terephthalic acid, and is a biodegradable resin excellent in toughness and flexibility. On the other hand, it is difficult for PBAT to be formed into a film by inflation molding alone.

  Inflation molding attaches an annular die to the tip of the extruder, puts a certain amount of air in the extruded molten resin tube and expands it, and blows air around the circumference of the tube, or molds while cooling naturally It is a thing. It is known that this inflation molding is difficult to mold in a thermoplastic elastomer, and PBAT having the same toughness and flexibility as a thermoplastic elastomer is also difficult to mold.

  Therefore, conventional PBAT is used as a modifier for other biodegradable resins having poor toughness and flexibility, or blended with polybutylene succinate (PBS), which is a biodegradable resin with good film-forming properties. The film was still being formed.

  The resin composite material manufactured in this embodiment has improved film-forming properties and facilitates inflation molding. The first mixture of gel-like clay mineral material and PBAT is mixed with a filler to form a second mixture, which is melt-kneaded to adjust the liquid medium content to blend the above-mentioned PBS. A resin composite material having the same effect as in the above case can be obtained.

  It is also possible to improve the biodegradation rate of the PBAT resin composite material or control the biodegradation rate by further mixing and kneading a starch-based substance with the second mixture. In some cases, the starch-based substance is used as the filler and the inorganic powder is not used.

  Here, FIG. 1 is a flowchart regarding determination of a compounding ratio of the resin composite material according to the embodiment. A procedure for determining the compounding of the resin composite material in order to develop the resin composite material, which is the material of the resin molded product, as a product will be described.

  As shown in Figure 1, we start by determining the concept of the product to be developed. First, the physical properties desired for the resin composite material are arranged (S11). Based on this, the synthetic resin as the continuous phase and the filler as the dispersed phase are selected (S12). Then, it is determined whether or not two fillers that affect the physical properties are blended (S13).

FIG. 2 shows the influence of each filler on the physical properties of the resin composite material in the case of an inorganic powder having a particle diameter of 100 μm or less (including a specific surface area of 10,000 cm ² / g or more) and the case of a starch-based material. Is a table summarizing. In FIG. 2, x is a physical property in which the property is deteriorated by mixing the filler, Δ is a property in which the property is not changed by mixing the filler, ◯ is a physical property in which the property is improved by mixing the filler, and ◎ is It is a physical property in which the characteristics are further improved by mixing the filler.

  Further, from the viewpoint of cost, the cost tends to increase when atomized calcium bicarbonate is used as the inorganic powder. When clinker ash or volcanic ash is adopted as the inorganic powder, it also leads to utilization of low unused resources, and the cost tends to be suppressed. Further, when a starch-based substance is used, the cost tends to be high.

  When the compounding determination of the two fillers is made based on this FIG. 2 (S13 Yes), the combination to be compounded from the two fillers is selected (S14). When it is determined that the two fillers are not blended (No in S13), the mixing / kneading conditions of the selected filler and the synthetic resin are examined (S15). When two fillers are selected (S14), the mixing / kneading conditions of the two selected fillers and the synthetic resin are examined (S15). After examining the mixing / kneading conditions, the evaluation is performed to determine whether or not to manufacture the resin composite material (S16 Yes No END).

(Example 1)
An example in which a masterbatch capable of forming a thin film by a dry blend that achieves both environment and low price is used as a product concept will be described. What is required in the production of resin composite materials is (1) the use of highly environmentally friendly polyolefins, (2) the production and production efficiency of PP / PE and dry blending in thin film molding, and (3) ) The unit price of the product is 20% or more lower than that of PP / PE dry-blended on the volume basis of the molded product.

  Therefore, (1) low density polyethylene (LDPE) having an MFR (melt flow rate) of 2 or more is preferably used as the synthetic resin, and (2) fly ash is preferably used as the filler. According to this embodiment, the interfacial adhesion between the synthetic resin and the filler can be improved. For this reason, polyethylene is generally used as a synthetic resin because it is highly hydrophobic and difficult to highly fill, and fly ash, which is cheap but spherical particles are easily scattered and has poor interfacial adhesion with the synthetic resin, is compounded. It becomes possible.

  Next, it is determined whether two fillers are needed. This product is judged as No (no) because it is used as a master batch in dry blending during molding.

  The mixture is mixed with 20 parts by weight of LDPE (Novatech LD / LF441MD1 manufactured by Nippon Polyethylene Corporation) and 2 parts by weight of a gel-like clay mineral substance, and fly ash (fly ash for concrete). (JIS A6201 type II) 80 parts by weight are mixed. The gel-like clay mineral substance is 1 part by weight of bentonite (manufactured by Kanesan Industry Co., Ltd., Kasaoka clay (powder) (250 mesh)), 3 parts by weight of water, liquid paraffin (manufactured by Kaneda Co., High Coal E- 7) 0.3 parts by weight.

  From the viewpoint of production efficiency, this blending can be said to be the upper limit of mixing of the inorganic powder when the inorganic powder is highly filled. Since the fly ash is spherical particles and has high wettability, the gel-like clay mineral-based substance is blended in a smaller proportion than when other fillers are used.

  In the step of gelling the clay mineral-based material, water is poured into bentonite with a predetermined composition to stir it to gel. Then, liquid paraffin is further added and stirred to prepare a predetermined gel-like clay mineral material.

  Next, the gel-like clay mineral material and LDPE are mixed in a predetermined composition to form a first mixture. Then, the first mixture and fly ash are stirred with a stirrer to form a second mixture. Then, a twin-screw extruder (NR-46 manufactured by Freesia Macross Co., Ltd.) is used as a kneading device (pressure vessel). The second mixture is introduced into the kneading device from the hopper in the upstream portion, and the excess water is discharged as vaporized gas at a pressure of 0.5 MPa while making the kneaded product at a set temperature of 180 ° C. downstream thereof. Further, after the vaporized gas is discharged at the same set temperature by the negative pressure at the downstream portion thereof, the kneaded material is cut out into pellets from the extraction portion and taken out.

  The water content (liquid medium content) of the resin composite material taken out was 0.1%. The moisture content was measured with an A & D moisture meter (ML-D) at a set temperature of 150 ° C. Although this temperature setting is higher than the melting point of the synthetic resin, it is measured on the safe side with reference to the temperature setting of the die portion during molding.

(Example 1B)
In Example 1B, the inorganic powder of Example 1A was replaced with fly ash by calcium carbonate (BF-300, manufactured by Shiraishi Calcim Co., Ltd.). Further, the gel-like clay mineral is 3 parts by weight, and the rest is prepared by the same procedure as in Example 1A. The liquid medium content in the prepared resin composite material was 0.1%. The moisture content was measured with an A & D moisture meter (ML-D) at a set temperature of 150 ° C. Although this temperature setting is higher than the melting point of the synthetic resin, it is measured on the safe side with reference to the temperature setting of the die portion during molding.

(Example 2)
Example 2 relates to the compounding of a masterbatch in which the product concept of Example 1 is changed from thin film molding to injection molding. Clinker ash is blended from the viewpoint of improving impact strength and weight reduction of the product, and the composition and blending ratio of the gel-like clay mineral-based substance are different from those of Example 1A from the viewpoint of improving moldability of injection molding.

  "Fly ash 80 parts by weight" of Example 1A is "fly ash 50 parts by weight, clinker ash 30 parts by weight" in Example 2, and "gelled clay mineral-based material 2 parts by weight" of Example 1A. In Example 2, “3 parts by weight of gel-like clay mineral substance” was added, and in Example 2, “0.3 parts by weight of liquid paraffin” was changed to “1 part by weight of liquid paraffin” in Example 2. Otherwise the formulation is the same as in Example 1A and is prepared by the same procedure as in Example 1A.

  That is, a mixture of 20 parts by weight of LDPE (Novatec LD / LF441MD1 manufactured by Nippon Polyethylene Corporation) and 3 parts by weight of a gel-like clay mineral-based material was added to fly ash (fly ash for concrete (JISA6201) type II). 50 parts by weight and 30 parts by weight of clinker ash were mixed. The gel-like clay mineral substance is bentonite (manufactured by Kanesan Industry Co., Ltd., Kasaoka clay (powder) (250 mesh)) 1 part by weight, water 3 parts by weight, liquid paraffin (manufactured by Kaneda Co., High Coal E- 7) Prepared with 1 part by weight.

  The liquid medium content in the produced resin composite material was 0.3%. The moisture content was measured with an A & D moisture meter (ML-D) at a set temperature of 180 ° C. Although this temperature setting is higher than the melting point of the synthetic resin, it is measured on the safe side with reference to the temperature setting of the die portion during molding.

(Comparative Example 1)
Comparative Example 1 of Example 1A is the same as Example 1 except that it is prepared by mixing the synthetic resin, the inorganic powder, and water without mixing the gel-like viscous mineral substance.

  That is, 20 parts by weight of LDPE (Novatech LD / LF441MD1 manufactured by Nippon Polyethylene Corporation), 80 parts by weight of fly ash (fly ash for concrete (JIS A6201) type II), and 1 part by weight of water were mixed. The liquid medium content in the prepared resin composite material was 0.1%. The moisture content was measured with an A & D moisture meter (ML-D) at a set temperature of 150 ° C. Although this temperature setting is higher than the melting point of the synthetic resin, it is measured on the safe side with reference to the temperature setting of the die portion during molding.

(Comparative example 2)
Comparative Example 2 of Example 2 is the same as Example 2 except that a gel-like viscous mineral-based substance is not mixed, but a synthetic resin, an inorganic powder and water are mixed.

  That is, 20 parts by weight of LDPE (Novatech LD / LF441MD1 manufactured by Nippon Polyethylene Corporation), 50 parts by weight of fly ash (fly ash for concrete (JIS A6201) type II), 30 parts by weight of clinker ash, and 1 part by weight of water were mixed. . The liquid medium content in the prepared resin composite material was 0.3%. The moisture content was measured with an A & D moisture meter (ML-D) at a set temperature of 180 ° C. Although this temperature setting is higher than the melting point of the synthetic resin, it is measured on the safe side with reference to the temperature setting of the die portion during molding.

(Comparative example 3)
Comparative Example 3 of Example 1A is the same as Example 1A except that the amount of water discharged from the kneading device is suppressed and the water content is 1% or more. The suppression of the amount of water to be discharged was based on not discharging water except for the setting temperature of 180 ° C. and the removal pressure of vaporized gas of 0.5 MPa. The liquid medium content in the prepared resin composite material was 1.1%. The moisture content was measured with an A & D moisture meter (ML-D) at a set temperature of 150 ° C.

  FIG. 3 is a table summarizing the physical properties of the resin composite materials according to Example 1A, Example 1B, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3. Here, the MFR of dry blend is measured by crushing a test piece. Further, as the dry blend resins of Example 1A, Example 1B, Comparative Example 1 and Comparative Example 3, Novatec LD / LF441MD1 was used, and the MFR was measured at 190 ° C. As the dry blend resin of Example 2 and Comparative Example 2, Novatec PP / MA3 was used, and the MFR was measured at 230 ° C.

  A general composite material of a synthetic resin and an inorganic powder is inferior in interfacial adhesiveness, and therefore, it is the biggest problem that impact strength is lowered. Therefore, the impact strength was measured for the physical properties of Examples and Comparative Examples. In addition, the density was measured from the viewpoint of thermal fluidity (MFR), which is a basic index of moldability, and unit price calculation on a volume basis.

  In Example 1A and Comparative Example 1, and in Example 2 and Comparative Example 2, it is examined whether or not there is an effect of using a gel-like clay mineral-based material and a synthetic resin as a mixture. The impact strength of Example 1 is 4 in Comparative Example 1 and the impact strength of Example 2 is 4 in Comparative Example 2 and the impact strength of Example 2 is 6 in both cases.

  In addition, in order to examine the physical properties when used as a masterbatch, in Example 1A, test pieces were prepared using LDPE used for thin film molding as a resin for dry blending. In the examples, the proportion of LDPE was 35 parts by weight with respect to 65 parts by weight, and the weight ratio of the filler in the molded product (test piece) was 52%.

  In Example 2, a test piece was prepared by using PP for injection molding as a resin for dry blending. In the examples, 10 parts by weight of PP was added to 90 parts by weight, and the proportion of the filler in the molded product (test piece) was 72%.

  In comparison with the impact strength 29 of Example 1A, Comparative Example 1 was 17, and the impact strength 10 of Example 2 was 10 and Comparative Example 2 was 6. In both cases, the impact strengths of Examples were compared. In the examples, it was confirmed that the intended product could be produced, and it was decided as the composition of each resin composite material. It should be noted that the description of the confirmation regarding other physical properties is omitted.

  Example 1A and Comparative Example 3 examine the effect of the moisture content of the resin composite material on the molding. FIG. 4 is a table showing the occurrence of defects in film molding. In FIG. 4, ◯ indicates that a good sheet was stably obtained, Δ indicates that a defective portion due to foaming rarely occurs but it is acceptable as a product, and × indicates a defective portion due to foaming. Indicates that the product cannot be used.

  Where there is almost no difference in physical properties in the table of FIG. 3, in order to compare the moldability in the table of FIG. 4, a T-die is attached to a Labo Plastomill (manufactured by Toyo Seiki Seisakusho) and a 0.2 mm film is extruded for comparison. did. The set temperature during molding was set in four patterns of 140 ° C., 160 ° C., 180 ° C. and 200 ° C. with reference to the LDPE molding temperature. In all cases, LDPE (Novatech LD / LF441MD1) used for film forming was used as a resin for dry blending, and the following formulation was used.

Example: 65 parts by weight of the resin composite material of Example 1A and 35 parts by weight of LDPE Comparative example: 65 parts by weight of the resin composite material of Comparative Example 3 and 35 parts by weight of LDPE

  As shown in FIG. 4, in the example, no defect was generated at any temperature, and the film could be molded well. On the other hand, in Comparative Example, foaming occurred at 180 ° C, and at 200 ° C, a good product could not be molded. It has been confirmed that it is necessary to set the content of the liquid medium in the resin composite material to 1% or less, although the molding failure varies greatly depending on the molding method and molding conditions.

  Example 1B is a modification of the inorganic powder of Example 1A. It is a comparison between calcium carbonate, which is the most typical filler as a resin composite material, and fly ash, which can be used without limitation by the present embodiment.

  As shown in FIG. 3, the impact strength of Example 1A was 7 and that of Example 1B was 7. Therefore, fly ash, which was conventionally considered to be inferior in strength to other inorganic powders, has the same physical properties as calcium carbonate. Was confirmed to have. Regarding the dry-blended product in the same manner as described above, the impact strength of 29 in Example 1A was 23, and that of Example 1B was 23. The fly ash exceeded the physical properties of calcium carbonate.

  In addition, regarding the density that affects the unit price of the product, since Example 1A is smaller than Example 1B, it can be seen that the use of fly ash is advantageous as the inorganic powder. Since fly ash has a lower unit price per weight than other inorganic powders, fly ash is preferably used. However, since fly ash is gray, it is unsuitable for products that require bright colors due to the addition of pigments.

(Example 3)
An example of a resin composite material of biodegradable mulch film for agriculture that replaces PE will be described. The physical properties required for this resin composite material are (1) that the synthetic resin is biodegradable, (2) that the filler has a fertilizer / soil improving effect, and (3) that it is within twice the PE product price. (4) Physical properties / strength and film-forming properties are comparable to those of PE products, and (5) Biodegradation rate can be controlled. Then, PBAT is selected as the synthetic resin of (1) and fly ash is selected as the filler of (2).

  Next, determine if two fillers are needed. This product is required to have (5) control of biodegradation rate in the required physical properties, etc. Therefore, it is difficult to control biodegradation rate with only fly ash as a filler. As the filler to be used, modified starch is selected as a starch-based substance that is effective in promoting the biodegradation rate. This is because, among the starch-based substances, the modified starch is the most inexpensive and stable supply.

  In Example 3A, 55 parts by weight of PBAT (manufactured by BASF, Ecoflex) and 1 part by weight of a gel-like clay mineral substance (same as Example 1A) were used as a mixture, and fly ash (same as Example 1A) was added to the mixture. ) Add 45 parts by weight.

  In Example 3B, 55 parts by weight of PBAT (manufactured by BASF, Ecoflex) and 1 part by weight of a gel-like clay mineral-based material (same as in Example 1A) were used as a mixture, and fly ash (same as in Example 1A). ) 43 parts by weight, and 2 parts by weight of modified starch (Korbon EX manufactured by Nippon Corn Starch Co., Ltd.).

  In Example 3C, 55 parts by weight of PBAT (manufactured by BASF, Ecoflex) and 1 part by weight of a gel-like clay mineral substance (same as in Example 1A) were used as a mixture, and fly ash (same as in Example 1A). ) 40 parts by weight and 5 parts by weight of modified starch (Korbon EX manufactured by Nippon Corn Starch Co., Ltd.) are mixed.

  Prepare these three examples by the same procedure as in Example 1A. The liquid medium contents in the prepared resin composite materials were all 0.1%. The moisture content was measured with an A & D moisture meter (ML-D) at a set temperature of 150 ° C. Although this temperature setting is higher than the melting point of the synthetic resin, it is measured on the safe side with reference to the temperature setting of the die portion during molding.

(Example 4)
In Example 4, the inorganic powder of Example 3A was changed from fly ash to calcium carbonate (BF-300 manufactured by Shiraishi Calcium Co., Ltd.). In addition, 3 parts by weight of a gel-like clay mineral is used, and otherwise the procedure is the same as in Example 3A. The water content in the prepared resin composite material was 0.1%. The moisture content was measured with an A & D moisture meter (ML-D) at a set temperature of 150 ° C. Although this temperature setting is higher than the melting point of the synthetic resin, it is measured on the safe side with reference to the temperature setting of the die portion during molding.

(Comparative example 4)
Comparative Example 4 of Example 3A was prepared by mixing the synthetic resin, the inorganic powder, and water without mixing the gel-like viscous mineral substance, and otherwise, the procedure was the same as that of Example 3A.

  That is, 55 parts by weight of PBAT (manufactured by BASF, Ecoflex), 45 parts by weight of fly ash (the same as in Example 1A), and 1 part by weight of water were mixed. The liquid medium content in the prepared resin composite material was 0.1%. The moisture content was measured with an A & D moisture meter (ML-D) at a set temperature of 150 ° C. Although this temperature setting is higher than the melting point of the synthetic resin, it is measured on the safe side with reference to the temperature setting of the die portion during molding.

  FIG. 5 is a table showing test results regarding film-forming properties in inflation molding of a resin composite material having PBAT in a continuous phase. Inflation molding was performed at the Ibaraki 1st factory of Shimizu Chemical Industry Co., Ltd. Six types of Example 3A, Example 3B, Example 3C, Example 4, Comparative Example 4, and PBAT (manufactured by BASF Corp., Ecoflex) alone were evaluated for film forming capability and productivity. . In this table, ◯ is possible, Δ is unstable, and x is impossible in “whether or not film can be formed”, and in “productivity”, ◯ is superior to LDPE, Δ is equivalent to LDPE, and x is inferior to LDPE. , Is shown.

  As shown in FIG. 5, PBAT could not be formed into a film by itself. Example 3A and Comparative Example 4 examine the effect of using a mixture of gel-like clay mineral material and PBAT. In Example 3A, film formation was possible, and the productivity was evaluated to be LDPE or higher. On the other hand, in Comparative Example, although film formation was possible although unstable, productivity was evaluated to be lower than that of LDPE. However, since it is not possible to form a film with PBAT alone, it can be seen that the filling of the inorganic powder has a certain effect.

  In each of Example 3B, Example 3C, and Example 4 in which the gel-like clay mineral-based material is mixed, film formation is possible, so that the effect of mixing the gel-like clay mineral-based material is large. I understand. In addition, since the productivity is lower in Examples 3B and 3C in which the starch-based material is mixed than in Examples 3A and 4 in which only the inorganic powder is filled, the gel-like clay mineral-based material and PBAT are mixed. It is understood that the resin composite material containing the inorganic powder is effective in improving the film forming suitability of PBAT.

  FIG. 6 is a table showing the test results for evaluating the biodegradation rate. Example 3A, Example 3B, Example 3C and PBAT alone were evaluated for their biodegradation rate. In the experiment, strip films each having a thickness of 30 μm, a width of 15 mm and a length of 100 mm are prepared. The same purchased compost was placed on a petri dish, a strip film was placed on the compost, placed in an incubator, and the rate of biodegradation was evaluated by visual observation. The preset temperature of the incubator was 55 ° C. The visual evaluation was carried out on a weekly basis, and the time point when it was considered to be almost degraded was taken as the number of days required for biodegradation.

  As shown in FIG. 6, Example 3C containing 5 parts by weight of modified starch was the earliest, 2 weeks, Example 3B containing 2 parts by weight of modified starch was 3 weeks, Example 3A containing no modified starch was 5 weeks, PBAT alone has become 6 weeks. From this, it was confirmed that it is possible to control the biodegradation rate by adding a starch-based substance.

In the resin composite material according to the present invention, a continuous phase of a synthetic resin formed by heat-fluidizing by heating , a monolayer exfoliated layered silicate nanosheet having a surface not chemically modified, and by the heating It is characterized by comprising at least a dispersed phase of a filler which is not melted and maintains a solid state, and the nanosheet becomes a bridge to be bonded to a molecular chain of the synthetic resin.

Claims (5)

A continuous phase of synthetic resin,
A monolayer exfoliated layered silicate, a nanosheet having a surface not chemically modified,
A resin composite material comprising at least a dispersed phase of a filler in which the nanosheets are bridged and bonded to a molecular chain of the synthetic resin. The resin composite material according to claim 1,
The filler is a resin composite material containing fly ash. The resin composite material according to claim 1 or 2,
The filler is a resin composite material containing at least one of a substance having a specific surface area of 10,000 cm ² / g or more and a starch substance. The resin composite material according to any one of claims 1 to 3,
A resin composite material in which the synthetic resin is a polybutylene adipate-butylene terephthalate copolymer (PBAT). The resin composite material according to any one of claims 1 to 4,
A resin composite material having a thickness of 1.0 mm or less.

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