JP2004018603A - Pellet and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide pellets which can prevent the dispersion failure of raw materials in an extruder and enables the continuous production of molded articles with an extruder for a long period, and to provide a method for producing the same. <P>SOLUTION: The pellets 1A constituting the raw material of a molded article produced by a molding method are characterized in that the pellets 1A comprise a mixture of the fine particles of a hydrophilic polymer with the fine particles of a polyolefin-based thermoplastic synthetic resin, vegetable fibers, and an inorganic compound, that the particle diameters of the fine particles are 30 to 200μm, that the water content of the pellets 1A is 5 to 30% based on the total weight of the pellets 1A, and that the fine particles are approximately uniformly dispersed in the pellets 1A. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a pellet constituting a raw material of a molded article produced by molding and a method for producing the pellet.
[0002]
[Prior art]
Japanese Patent Application Laid-Open No. 2000-273800 discloses that a paper component, a thermoplastic synthetic resin, a vegetable material, and water are kneaded while being heated inside an extruder, and are synthesized with the paper component by utilizing vaporization of water inside the extruder. A foamed material obtained by foaming a mixture of a resin and a plant material at a predetermined magnification and a method for producing the foamed material are disclosed.
[0003]
This foamed material uses crushed waste paper as a paper component, uses a powdery polypropylene homopolymer as a synthetic resin, and uses corn starch as a plant material. This foam material contains crushed waste paper and corn starch, which helps to use resources effectively and incinerates the foam material compared to the case where the foam material is made only of synthetic resin. Burning calories at the time can be reduced.
[0004]
[Problems to be solved by the invention]
In the foamed material disclosed in the above publication, since the specific gravity and bulk of each of the crushed product and the powdery polypropylene homopolymer and the corn starch are different, they were not uniformly dispersed inside the extruder during the production of the foamed material, and were manufactured. Crushed materials and corn starch may be unevenly distributed in a part of the foam material. If the crushed material or the corn starch is unevenly distributed in a part of the foam material, the strength of the foam material in that part is significantly reduced.
[0005]
During the production of this foam material, due to poor dispersion of the crushed material inside the extruder, the crushed material concentrates on the screw of the extruder, the crushed material is entangled with the screw, and the biting of the screw with the mixture becomes unstable, These may cause pulsation in the rotation of the screw, resulting in excessive foaming or poor foaming of the mixture. Also, during the production of this foam material, the crushed material may concentrate on a part of the die due to poor dispersion of the crushed material inside the extruder, and the die may be clogged. It becomes difficult to manufacture.
[0006]
An object of the present invention is to provide a pellet capable of preventing poor dispersion of raw materials in an extruder and continuously producing a molded product using the extruder for a long time, and a method for producing the pellet. .
[0007]
[Means for Solving the Problems]
The premise of the present invention for solving the above-mentioned problems is a pellet constituting a raw material of a molded article produced by molding.
[0008]
The feature of the present invention based on the above premise is that the pellet is formed from at least one of a first fine powder formed of a hydrophilic polymer, a polyolefin-based thermoplastic synthetic resin, a plant fiber, and an inorganic compound. A mixture with a second fine powder, containing a predetermined amount of water, a particle diameter of the first and second fine powders in a range of 30 to 200 μm, and a water content of the pellets, The first and second fine powders are in a range of 5 to 30% with respect to the weight, and are substantially uniformly dispersed in the pellets.
[0009]
As an example of an embodiment of the present invention, the weight ratio of the hydrophilic polymer to the total weight of the pellets is 5 to 69.5%, and the weight ratio of the synthetic resin to the total weight of the pellets is 10 to 50%. The weight ratio of the plant fiber to the total weight of the pellets is in the range of 20 to 60%, and the weight ratio of the inorganic compound to the total weight of the pellets is in the range of 0.5 to 35%.
[0010]
As another example of the embodiment of the present invention, the pellet collapses at a pressure of 100 to 490 N and melts at a temperature of 150 to 190 ° C.
[0011]
As another example of the embodiment of the present invention, the bulk specific gravity of the pellet is in the range of 0.2 to 1.0.
[0012]
As another example of the embodiment of the present invention, the pellet has a substantially columnar shape, the length of the pellet is in a range of 0.5 to 10.0 mm, and the diameter of the pellet is 1.0 to 1.0 mm. It is in the range of 5.0 mm.
[0013]
Another premise of the present invention for solving the above-mentioned problems is a method for producing pellets constituting a raw material of a molded product produced by molding.
[0014]
The feature of the present invention in the production method is that the method is formed from a first fine powder formed of a hydrophilic polymer, at least one of a polyolefin-based thermoplastic synthetic resin, a plant fiber, and an inorganic compound. Water, and mixing the first and second fine powders with the water to produce a flowable mixture; and wet-granulating the flowable mixture, followed by drying. The first and second fine powders have a particle diameter in the range of 30 to 200 μm, and the proportion of the water added in the mixture production step is the same as the mixture production step. In the range of 20 to 50% based on the total weight of the first and second fine powders kneaded.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
The details of the pellet and the method for producing the pellet according to the present invention will be described below with reference to the accompanying drawings.
[0016]
FIG. 1 is a perspective view of a pellet 1A shown as an example. The pellet 1A constitutes a raw material of a foam material 7 (molded product) made by using an extrusion molding technique (see FIG. 3).
[0017]
The pellet 1A is composed of a fine powder P1 (first fine powder) formed of the hydrophilic polymer 2, and fine powders P2, P3 formed of the polyolefin-based thermoplastic synthetic resin 3, the plant fiber 4, and the inorganic compound 5. P4 (second fine powder) is mixed at a predetermined ratio (see FIG. 2). The pellet 1A contains a predetermined amount of water.
[0018]
In the pellet 1A, a fine powder P1 of the hydrophilic polymer 2, a fine powder P2 of the synthetic resin 3, a fine powder P3 of the plant fiber 4, and a fine powder P4 of the inorganic compound 5 are substantially uniformly dispersed. The particle size of the fine powders P1, P2, P3, P4 is in the range of 30 to 200 μm. In the pellet 1A, the fine powders P1, P2, P3, and P4 are substantially invisible.
[0019]
The pellet 1A is a solid having a columnar shape, and has a length L1 of 0.5 to 10.0 mm and a diameter L2 of 1.0 to 5.0 mm. The pellet 1A has a bulk specific gravity in the range of 0.2 to 1.0, disintegrates at a pressure of 100 to 490 N, and melts at a temperature of 150 to 190 ° C.
[0020]
As the hydrophilic polymer 2, at least one of a plant natural polymer and a synthetic polymer is used. The hydrophilic polymer 2 functions as a binder for bonding the synthetic resin 3, the plant fiber 4, and the inorganic compound 5.
[0021]
Starch can be used as a plant-based natural polymer. As the starch, at least one of potato, sweet potato, corn starch, rice starch, wheat starch, konjac, tapioca, modified starch, and modified starch can be used. As the plant-based natural polymer, at least one of glue, agar, bran, nuka, okara, and gelatin can be used in addition to starch.
[0022]
For the synthetic polymer, at least one of polyvinyl alcohol, acrylate, maleate, and fat wax can be used. The fine powder P1 of the hydrophilic polymer 2 can be produced by finely pulverizing a plant-based natural polymer and a synthetic polymer with a pulverizer.
[0023]
As the polyolefin-based thermoplastic synthetic resin 3, one of polypropylene and polyethylene or a resin obtained by mixing them at a predetermined ratio is used.
[0024]
As the polypropylene, at least one of block polymerized polypropylene, random polymerized polypropylene, homopolymerized polypropylene, metallocene catalyzed polypropylene, and modified polypropylene can be used.
[0025]
As the polyethylene, at least one of low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, metallocene-catalyzed polyethylene, and modified polyethylene can be used.
[0026]
As the fine powder P2 of the synthetic resin 3, polymer particles generated in the polymerization process of the synthetic resin 3 can be used. Further, the fine powder P2 of the synthetic resin 3 can also be produced by finely pulverizing the massive synthetic resin 3 with a pulverizer.
[0027]
Paper is used for the vegetable fiber 4. Virgin paper or waste paper can be used as the paper. As the paper, broken paper or broke generated when the paper is manufactured can also be used. It is preferable to use paper that does not contain chlorine and a fluorescent whitening agent. The vegetable fiber 4 made of waste paper preferably has a cellulose component of 95% or more. The fine powder P3 of the plant fiber 4 formed from paper can be produced by finely pulverizing paper with a pulverizer.
[0028]
Pulp before papermaking can also be used for the vegetable fiber 4. The fine powder P3 of the plant fiber 4 formed from pulp can be produced by crushing pulp with a crusher. As the fine powder P3 of the plant fiber 4 made from pulp, it is preferable to use one having a lignin component of 1% or less.
[0029]
As the pulp, at least one of mechanical pulp, chemical mechanical pulp, semi-chemical pulp, and chemical pulp can be used. As the pulp, wood pulp is preferably used, but at least one of rag pulp, stalk pulp, bast pulp and the like can be mixed with wood pulp. It is preferable to use a pulp that does not contain chlorine and an optical brightener.
[0030]
As the plant fiber 4, a plant itself can be used in addition to paper and pulp. The fine powder P3 of the plant fiber 4 formed from the plant can be produced by pulverizing the plant with a crusher. As the plant, at least one of pagasu, kenaf, reed, hemp, mitsumata, kozo, gambi, and bamboo can be used.
[0031]
As the inorganic compound 5, at least one of titanium oxide, talc, calcium carbonate, clay, magnesium sulfate, calcium sulfate, barium sulfate, kaolin, aluminum hydroxide, magnesium hydroxide, zinc white, calcium shell, and coal is used. ing. The fine powder P4 of the inorganic compound 5 can be produced by finely pulverizing the inorganic compound 5 with a pulverizer if the compound is a lump.
[0032]
FIG. 2 is a process schematic diagram showing a method of manufacturing the pellet 1A of FIG. The method for producing the pellet 1A is formed from a mixture production step S1 for producing the fluid mixture 6 using the kneader 11 and a pellet production step S2 for producing the pellet 1A from the mixture 6 using the granulator 12. Have been.
[0033]
In the mixture production step S1, fine powders P1, P2, P3, and P4 (first and second fine powders) of the hydrophilic polymer 2, the polyolefin-based thermoplastic synthetic resin 3, the plant fiber 4, and the inorganic compound 5 are kneaded. 11 and water W is injected into the kneader 11. In the kneader 11, the fine powders P1, P2, P3, and P4 are kneaded with water W by rotation of a screw (not shown) installed therein, and a viscous clay-like fluid mixture 6 is produced. You.
[0034]
The ratio of the water W injected into the kneader 11 (the weight ratio of the water added in the mixture production step) is determined by the total weight of the fine powders P1, P2, P3, and P4 supplied to the kneader 11 (The total weight of the first and second fine powders). The temperature of the water W is in the range of 1 to 30C. Tap water can be used as the water W. The water W is not particularly limited, and may be any of soft water, hard water, and pure water.
[0035]
When the ratio of water W injected into the kneader 11 is less than 20%, the fine powders P1, P2, P3, and P4 of the hydrophilic polymer 2, the synthetic resin 3, the plant fiber 4, and the inorganic compound 5 are sufficiently kneaded. And a fluid mixture 6 cannot be produced. When the ratio of the water W injected into the kneader 11 exceeds 50%, the viscosity of the mixture 6 is significantly reduced, and it is necessary to evaporate the water by heating the mixture 6 in a pellet manufacturing step S2 described later. Further, when the mixture 6 is heated to evaporate water, the fine powder P1 of the hydrophilic polymer 2 contained therein is transformed into a paste, and the viscosity of the mixture 6 is significantly increased. When the temperature of the water W injected into the kneading machine 11 exceeds 30 ° C., the fine powder P1 of the hydrophilic polymer 2 is changed into a paste, depending on the kind of the hydrophilic polymer 2 to be kneaded. There are cases.
[0036]
In the pellet manufacturing step S2, the mixture 6 discharged from the kneader 11 flows into the screw extrusion granulator 12 from the hopper 14 through the pipe 13. Inside the granulator 12, the mixture 6 moves from the rear end 12a to the front end 12b of the granulator 12 while being pressurized by rotation of a screw (not shown).
[0037]
The mixture 6 is discharged to the outside of the granulator 12 through a punching plate (not shown) attached to the tip 12b of the granulator 12. The mixture 6 is formed into a cylindrical shape by a large number of circular holes formed in the punching plate, and is cut into a predetermined length. Thereafter, the mixture 6 is air-dried to produce a large number of pellets 1A.
[0038]
In the method for producing the pellet 1A, the fine powders P1, P2, P3, and P4 of the hydrophilic polymer 2, the synthetic resin 3, the plant fiber 4, and the inorganic compound 5 are sufficiently kneaded with the water W. The fine powders P1, P2, P3, and P4 can be substantially uniformly dispersed in 1A. Since the fine powders P1, P2, P3, and P4 have a particle diameter in the range of 30 to 200 μm, the specific gravities and bulks of the fine powders P1, P2, P3, and P4 do not greatly differ. Either P3 or P4 is not localized in a part of the pellet 1A.
[0039]
FIG. 3 is a process schematic diagram showing a method for producing a foam material 7 made from the pellet 1A of FIG. The foam material 7 is manufactured using the extruder 15, and is formed into a plate shape by a die (not shown) attached to the tip 15b of the extruder 15.
[0040]
In the method for producing the foam material 7, a large number of pellets 1 </ b> A are charged from a hopper 16 attached to a rear end 15 a of the extruder 15, and the pellets 1 </ b> A enter the inside of the extruder 15.
[0041]
Inside the extruder 15, the pellet 1A is heated, and the pellet 1A is kneaded while being pressurized by rotation of a screw (not shown) of the extruder 15. Inside the extruder 15, the hydrophilic polymer 2 and the synthetic resin 3 are dissolved, and the pellet 1A becomes a high-temperature fluid (not shown) at a predetermined temperature. In the fluid, fine powders P3 and P4 of the plant fiber 4 and the inorganic compound 5 are substantially uniformly dispersed. In addition, since the pellet 1A collapses at a pressure of 100 to 490 N, the pellet 1A can be easily crushed by rotating the screw.
[0042]
When the pellet 1A changes into a high temperature fluid inside the extruder 15, the moisture contained in the pellet 1A instantaneously evaporates, and the moisture changes to steam having a volume of about 1200 times or more the volume before vaporization. Many bubbles 8 are formed inside the fluid by vaporization of water. At the moment when the fluid is extruded from the die, the fluid expands to a predetermined magnification with the expansion of the bubble 8. After being extruded from the die, the fluid is cooled and solidified into a plate-like foam material 7.
[0043]
In the method for manufacturing the foam material 7 shown in FIG. 3, since the pellets 1A in which the fine powders P1, P2, P3, and P4 are substantially uniformly dispersed are used, a fluid formed by heating and kneading the pellets 1A is used. The fine powders P3 and P4 can be uniformly dispersed, and the fine powders P3 and P4 are not unevenly distributed in a part of the manufactured foam material 7, and the strength of the foam material 7 is partially reduced. Never.
[0044]
In the foam material 7, the hydrophilic polymer 2 forms a film that covers the bubbles 8. The expansion ratio of the foaming material 7 is 20 to 80 times per unit volume of the fluid before foaming. The burning calories of the foam 7 are in the range of 4500 to 6000 kcal / kg.
[0045]
In the extruder 15, the pellet 1A that has entered the inside is heated to 150 to 190C. If the heating temperature of the pellet 1A is lower than 150 ° C., the fine powders P1 and P2 of the hydrophilic polymer 2 and the synthetic resin 3 do not dissolve inside the extruder 15, and the pellet 1A cannot be made into a high-temperature fluid. When the heating temperature of the pellet 1A exceeds 190 ° C., the properties of the hydrophilic polymer 2, the synthetic resin 3, and the plant fiber 4 change, and in particular, the plant fiber 4 becomes yellowed or darkened, and the foaming material 7 becomes The color may change.
[0046]
In the pellet 1A, the weight ratio of the hydrophilic polymer 2 to the total weight is 5 to 69.5%, and the weight ratio of the synthetic resin 3 to the total weight is in the range of 10 to 50%. In the pellet 1A, the weight ratio of the plant fiber 4 to the total weight is 20 to 60%, and the weight ratio of the inorganic compound 5 to the total weight is in the range of 0.5 to 35%. The weight ratio of the hydrophilic polymer 2 to the total weight of the pellet 1A is preferably in the range of 20 to 69.5%.
[0047]
In the method for producing the pellet 1A, the weight ratio of the hydrophilic polymer 2 to the total weight of the fluid mixture 6 produced by the kneader 11 is 5 to 69.5%, and the synthetic ratio is based on the total weight of the fluid mixture 6. The weight ratio of the resin 3 is 10 to 50%, the weight ratio of the plant fiber 4 to the total weight of the fluid mixture 6 is 20 to 60%, and the weight ratio of the inorganic compound 5 to the total weight of the fluid mixture 6 is 0.5 to 50%. It is in the range of 35%.
[0048]
If the weight ratio of the hydrophilic polymer 2 is less than 5%, the adhesive function of the hydrophilic polymer 2 cannot be sufficiently utilized, so that the synthetic polymer 3, the plant fiber 4 and the inorganic compound 5 Cannot be bonded, and the pellet 1A having a predetermined shape cannot be manufactured.
[0049]
If the weight ratio of the synthetic resin 3 is less than 10%, the strength of the foam 7 produced from the pellet 1A is significantly reduced, and the foam 7 is easily broken. If the weight ratio of the synthetic resin 3 exceeds 50%, the calorific value of the pellet 1A increases, and as a result, the caloric value of the foam 7 produced from the pellet 1A exceeds 6000 kcal / kg.
[0050]
If the weight ratio of the plant fiber 4 is less than 20% and the weight ratio of the inorganic compound 5 is less than 0.5%, the combustion calories of the pellet 1A cannot be reduced, and the combustion calories of the foam 7 produced from the pellet 1A. Can not be reduced.
[0051]
If the weight ratio of the plant fiber 4 exceeds 60% or the weight ratio of the inorganic compound 5 exceeds 35%, the plant fiber 4 or the inorganic compound 5 which does not show fluidity even when heated may be generated inside the extruder 15. The flowability of the fluid is hindered, and a fixed amount of the fluid cannot be extruded from the die, resulting in poor extrusion of the fluid. Also, when producing the foam 7 from the pellets 1A, the plant fiber 4 concentrates on a part of the die, which may cause clogging of the die. Becomes difficult. Further, the strength of the foam 7 produced from the pellet 1A is reduced.
[0052]
The water content of the pellet 1A is in the range of 5 to 30% based on the total weight. If the moisture content of the pellet 1A is less than 5%, the foaming of the high-temperature fluid inside the extruder 15 becomes insufficient when producing the foamed material 7 using the pellet 1A, and the foamed material produced from the pellet 1A The expansion ratio of No. 7 is 20% or less. If the moisture content of the pellet 1A exceeds 30%, the pellet 1A becomes extremely brittle, and easily breaks down at a pressure of less than 100N, and cannot maintain its shape.
[0053]
If the length of the pellet 1A exceeds 10.0 mm and the diameter exceeds 5.0 mm, the pellet 1A becomes unnecessarily large, and the pellet 1A does not rapidly disintegrate and dissolve inside the extruder 15; In some cases, pulsation may occur in the screw and the rotation of the screw may cause excessive fluid or excessive foaming inside the extruder 15. If the bulk specific gravity of the pellet 1A is less than 0.2, the screw of the extruder 15 may run idle and pulsation may occur in the rotation of the screw.
[0054]
When the particle diameter of the fine powders P1, P2, P3, and P4 of the hydrophilic polymer 2, the synthetic resin 3, the vegetable fiber 4, and the inorganic compound 5 is less than 30 μm, a plurality of particles are required to process them into the particle diameter of less than 30 μm. Since a pulverizing step is required, the production cost of the pellet 1A increases. If the particle size of the fine powders P1, P2, P3, and P4 exceeds 200 μm, the fine powders P1, P2, P3, and P4 cause poor dispersion during the production of the pellet 1A, and the fine powders P1, P2, and P2 are added to the pellet 1A. P3 and P4 cannot be uniformly dispersed.
[0055]
FIG. 4 is a perspective view of a pellet 1B shown as another example. The pellet 1B constitutes a raw material of a foamed material 7 (molded product) made by using an extrusion molding technique, similarly to that of FIG. 1 (see FIG. 6).
[0056]
The pellet 1B is composed of a fine powder P1 (first fine powder) formed from the hydrophilic polymer 2 and fine powders P3 and P4 (second fine powder) formed from the plant fiber 4 and the inorganic compound 5. This is a mixture mixed at a predetermined ratio (see FIG. 5). The pellet 1B is a solid having a prismatic shape and contains a predetermined amount of water.
[0057]
The water content relative to the total weight of the pellet 1B and the bulk specific gravity of the pellet 1B are the same as those in FIG. The pellet 1B disintegrates at a pressure of 100 to 490N and melts at a temperature of 150 to 190C.
[0058]
In the pellet 1B, a fine powder P1 of the hydrophilic polymer 2, a fine powder P3 of the plant fiber 4, and a fine powder P4 of the inorganic compound 5 are substantially uniformly dispersed. The fine powders P1, P3, and P4 have a particle diameter in the range of 30 to 200 μm. The same materials as those in FIG. 1 are used for the hydrophilic polymer 2, the plant fiber 4, and the inorganic compound 5.
[0059]
FIG. 5 is a process schematic diagram showing a method for manufacturing the pellet 1B of FIG. The method for producing the pellets 1B is the same as that in FIG. 1, in which a mixture production step S1 for producing a fluid mixture 6 using a kneader 11 and a pellet 1B from the mixture 6 using a granulator 12 And a pellet manufacturing step S2.
[0060]
In the mixture production step S1, fine powders P1, P3, and P4 of the hydrophilic polymer 2, the plant fiber 4, and the inorganic compound 5 are charged into the kneader 11, and water W is injected into the kneader 11. In the kneader 11, the fine powders P1, P3 and P4 are kneaded together with the water W by the rotation of the screw, and a viscous clay-like fluid mixture 6 is produced. The ratio of the water W injected into the kneader 11 (the weight ratio of the water added in the mixture production step) and the temperature of the water W are the same as those in FIG.
[0061]
In the pellet manufacturing step S2, the mixture 6 flows into the screw extrusion granulator 12 from the hopper 14 through the pipe 13. Inside the granulator 12, the mixture 6 moves toward the tip 12 b of the granulator 12 while being pressurized by rotation of a screw (not shown). The mixture 6 is discharged to the outside of the granulator 12 from a punching plate (not shown) attached to the tip 12b of the granulator 12. The mixture 6 is formed into a prism shape by a large number of square holes formed in the punching plate, and is cut into a predetermined length. Thereafter, the mixture 6 is air-dried to produce a large number of pellets 1B.
[0062]
In the manufacturing method of the pellet 1B, the fine powders P1, P3, and P4 of the hydrophilic polymer 2, the plant fiber 4, and the inorganic compound 5 are sufficiently kneaded together with the water W. P1, P3, and P4 can be substantially uniformly dispersed. Since the fine powders P1, P3, and P4 have a particle diameter in the range of 30 to 200 μm, the specific gravity and bulk of the fine powders P1, P3, and P4 do not greatly differ. Is not unevenly distributed on a part of the pellet 1A.
[0063]
FIG. 6 is a process schematic diagram showing a method for manufacturing the foamed material 7 made from the pellet 1B of FIG. The foam material 7 is manufactured using an extruder 15, and is formed into a plate by extruding from a die (not shown) attached to the extruder 15.
[0064]
A predetermined amount of the fine powder P2 of the polyolefin-based thermoplastic synthetic resin 3 is put into the hopper 16 of the extruder 15 together with the large number of pellets 1B. Inside the extruder 15, the pellet 1B and the fine powder P2 of the synthetic resin 3 are heated, and are kneaded by the rotation of a screw (not shown) of the extruder 15, so that the hydrophilic polymer 2 and the synthetic resin 3 are mixed. 3 and the fine powders P1 and P2 are dissolved to form a high-temperature fluid at a predetermined temperature.
[0065]
Inside the extruder 15, the moisture contained in the pellets 1B is instantaneously vaporized, and the moisture changes into a gas having a volume of about 1200 times or more the unit volume before vaporization. 8 are formed. At the moment the fluid is extruded from the die, it expands to a given magnification with the expansion of the bubbles 8. After being extruded from the die, the fluid is cooled and solidified into a plate-like foam material 7.
[0066]
In the foam material 7, the hydrophilic polymer 2 forms a film that covers the bubbles 8. The expansion ratio of the foaming material 7 is 20 to 80 times per unit volume of the fluid before foaming. The burning calories of the foam 7 are in the range of 4500 to 6000 kcal / kg. The heating temperature of the extruder 15 for the pellet 1B and the fine powder P2 is the same as that in FIG.
[0067]
In the method for manufacturing the foam material 7 shown in FIG. 6, since the pellets 1B in which the fine powders P1, P3, and P4 are substantially uniformly dispersed and the fine powder P2 of the synthetic resin 3 are used, the pellets 1A are heated and kneaded. Thus, the fine powders P3 and P4 can be uniformly dispersed in the fluid formed, and any of the fine powders P3 and P4 is not unevenly distributed in a part of the foamed material 7 produced. There is no partial decrease in strength.
[0068]
In the pellet 1B, the weight ratio of the hydrophilic polymer 2 to the total weight is 5 to 69.5%, the weight ratio of the plant fiber 4 to the total weight is 20 to 60%, and the weight of the inorganic compound 5 to the total weight. The ratio is in the range of 0.5-35%. The weight ratio of the hydrophilic polymer 2 to the total weight of the pellet 1B is preferably in the range of 20 to 69.5%.
[0069]
In the method for producing the pellet 1B, the weight ratio of the hydrophilic polymer 2 to the total weight of the fluid mixture 6 produced by the kneader 11 is 5 to 69.5%, The weight ratio of the fibers 4 is in the range of 20 to 60%, and the weight ratio of the inorganic compound 5 to the total weight of the fluid mixture 6 is in the range of 0.5 to 35%.
[0070]
When the weight ratio of the hydrophilic polymer 2 is less than 5%, the adhesive force of the hydrophilic polymer 2 is reduced, and the plant fiber 4 and the inorganic compound 5 cannot be adhered by the hydrophilic polymer 2, and the hydrophilic polymer 2 has a predetermined shape. Pellet 1B cannot be manufactured.
[0071]
If the weight ratio of the plant fiber 4 is less than 20% and the weight ratio of the inorganic compound 5 is less than 0.5%, the calorie burned of the pellet 1B cannot be reduced, and as a result, the foam 7 produced from the pellet 1B Calories burned exceed 6000 kcal / kg.
[0072]
If the weight ratio of the plant fiber 4 exceeds 60% or the weight ratio of the inorganic compound 5 exceeds 35%, the plant fiber 4 or the inorganic compound 5 which does not show fluidity even when heated may be generated inside the extruder 15. The flowability of the fluid is hindered, and a fixed amount of the fluid cannot be extruded from the die, resulting in poor extrusion of the fluid. Also, when producing the foam 7 from the pellets 1B, the plant fiber 4 concentrates on a part of the die, which may cause clogging of the die. Becomes difficult.
[0073]
In the production method for producing the foamed material 7 from the pellets 1B, the weight ratio of the synthetic resin 3 to be charged into the extruder 15 is in the range of 10 to 50% based on the total weight of the pellets 1B to be charged into the extruder 15. Is preferred.
[0074]
The pellets are at least one fine powder P2, P3 selected from the fine powder P1 (first fine powder) of the hydrophilic polymer 2, the polyolefin thermoplastic synthetic resin 3, the plant fiber 4, and the inorganic compound 5. , P4 (second fine powder). For example, the pellet is a mixture of the fine powder P1 of the hydrophilic polymer 2 and the fine powder P2 of the synthetic resin 3, the pellet is a mixture of the fine powder P1 of the hydrophilic polymer 2 and the fine powder P3 of the plant fiber 4, and the pellet is A mixture of the fine powder P1 of the hydrophilic polymer 2 and the fine powder P4 of the inorganic compound 5 may be used. Further, the pellet is a mixture of the fine powder P1 of the hydrophilic polymer 2 and the synthetic resin 3 and the fine powders P2 and P3 of the plant fiber 4, and the pellet is the mixture of the fine powder P1 of the hydrophilic polymer 2 and the synthetic resin 3 and the inorganic compound 5. And fine powders P2 and P4 of the above.
[0075]
The shape of the pellet is not limited to the illustrated columnar shape or prismatic shape, and the shape can be changed in the pellet manufacturing process.
[0076]
【The invention's effect】
The pellets according to the present invention include a fine powder (first fine powder) formed from a hydrophilic polymer, and a fine powder formed from at least one of a polyolefin-based thermoplastic synthetic resin, a plant fiber, and an inorganic compound. (Second fine powder), and the fine powder is substantially uniformly dispersed in the pellets. The pellets have a particle diameter of 30 to 200 μm in the fine powder forming the pellets, and the specific gravity and bulk of the fine powders are not largely different, and the hydrophilic polymer, the synthetic resin, the plant fiber, and the inorganic compound are used. Either of the fine powders is not unevenly distributed on a part of the pellet.
[0077]
This pellet can prevent poor dispersion of the fine powder inside the extruder when manufacturing a molded product using the pellet, and any one of the fine powder of the plant fiber and the inorganic compound is part of the molded product. And the strength of the molded product can be prevented from lowering.
[0078]
The pellets have a water content in the range of 5 to 30% based on the total weight of the pellets. When the pellets are put into an extruder, the pellets are dissolved to become a high-temperature fluid, and water is vaporized. Thus, a foam material can be easily produced using the pellets.
[0079]
Pellets containing vegetable fibers and inorganic compounds can reduce the calories burned during incineration of molded products produced from the pellets, as compared to the case where they are formed only of synthetic resin.
[0080]
ADVANTAGE OF THE INVENTION In the manufacturing method of the pellet which concerns on this invention, the fine powder which forms a pellet can be uniformly disperse | distributed, and the uneven distribution of the fine powder in a pellet can be prevented. Therefore, when manufacturing a molded product from pellets using an extruder, the fine powder is uniformly dispersed in the fluid flowing inside the extruder, and a fixed amount of fluid is smoothly extruded from the die of the extruder. The molding can be continuously performed for a long time using an extruder without causing clogging of a die.
[Brief description of the drawings]
FIG. 1 is a perspective view of a pellet shown as an example.
FIG. 2 is a schematic process diagram showing an example of a method for producing the pellet of FIG.
FIG. 3 is a schematic process diagram showing a method for producing a foamed material made from the pellets of FIG.
FIG. 4 is a perspective view of a pellet shown as another example.
FIG. 5 is a schematic process diagram showing an example of a method for producing the pellet of FIG.
FIG. 6 is a process schematic diagram showing a method for producing a foamed material made from the pellets of FIG.
[Explanation of symbols]
1A pellet
1B pellet
2 hydrophilic polymer
3 Polyolefin synthetic resin
4 Plant fiber
5 Inorganic compounds
6. Fluid mixture
7 Foam (molded product)
11 Kneading machine
12 Granulator
15 Extruder
L1 length
L2 diameter
P1 Fine powder of hydrophilic polymer (first fine powder)
P2 Fine powder of polyolefin synthetic resin (second fine powder)
P3 Fine powder of vegetable fiber (second fine powder)
P4 Fine powder of inorganic compound (second fine powder)
S1 mixture production process
S2 Pellet manufacturing process
W water

Claims (6)

In the pellets constituting the raw material of the molded product made by the molding process,
The pellet is a mixture of a first fine powder formed from a hydrophilic polymer, and a second fine powder formed from at least one of a polyolefin-based thermoplastic synthetic resin, plant fiber, and an inorganic compound. Contains a predetermined amount of water,
The particle diameter of the first and second fine powders is in the range of 30 to 200 μm, the water content of the pellets is in the range of 5 to 30% based on the total weight of the pellets, and the first and second fine powders are in the range of 5 to 30%. The pellet, wherein the fine powder is substantially uniformly dispersed in the pellet. The weight ratio of the hydrophilic polymer to the total weight of the pellets is 5 to 69.5%, the weight ratio of the synthetic resin to the total weight of the pellets is 10 to 50%, and the weight of the plant fiber to the total weight of the pellets. The pellet according to claim 1, wherein the weight ratio is 20 to 60%, and the weight ratio of the inorganic compound to the total weight of the pellet is 0.5 to 35%. The pellet according to claim 1, wherein the pellet disintegrates at a pressure of 100 to 490 N and melts at a temperature of 150 to 190 ° C. 4. The pellet according to any one of claims 1 to 3, wherein the bulk specific gravity of the pellet is in the range of 0.2 to 1.0. The said pellet is exhibiting substantially columnar shape, the length of the said pellet is in the range of 0.5-10.0 mm, and the diameter of the said pellet is in the range of 1.0-5.0 mm. 4. The pellet according to any one of 4. In a method for producing pellets constituting a raw material of a molded product made by molding,
The method comprises adding water to a first fine powder formed from a hydrophilic polymer, and a second fine powder formed from at least one of a polyolefin-based thermoplastic synthetic resin, plant fiber, and an inorganic compound. A mixture producing step of producing a fluid mixture by kneading the first and second fine powders with the water, and a pellet producing step of producing the pellets by wet granulating the fluid mixture and then drying. Formed from
The particle diameter of the first and second fine powders is in the range of 30 to 200 μm, and the ratio of the water added in the mixture manufacturing step is the same as that of the first and second fine powders kneaded in the mixture manufacturing step. The above method, wherein the amount is in the range of 20% to 50% by weight.

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