JP5466718B2 - Method for producing extrusion molded body - Google Patents

Description

  The present invention relates to a method for producing an extrusion-molded body, and more particularly to an industrial production method for an extrusion-molded body having high rigidity, excellent surface transferability by a shaping mold, and capable of high-speed molding.

  Conventionally, a composite material is often obtained by kneading a thermoplastic resin and an inorganic material. Improve the impact strength and elastic modulus of the composite by filling fine calcium carbonate, or linear expansion of thermoplastic resin by filling fibers such as glass fiber and wollastonite, acicular reinforcing filler The rate has been improved. However, it is difficult to set the filling rate to 35 (volume%) or more in extrusion molding.

  Although a high filling rate has been proposed, however, there is a problem. For example, a composite filled with coal ash up to 80% by weight is known (see Patent Document 1), but filling with a reinforcing filler is known. There is a problem that the effect of improving the elastic modulus is small with respect to the amount.

Further, when an inorganic material is filled in a thermoplastic resin in the extrusion molding method, the elongation at break of the resin at the time of melting becomes smaller as the filling amount increases. Further, a shearing force is applied to the molten resin when passing through the extrusion mold. In such a case, when the elongation at break of the molten resin is small, the surface of the molded product is rolled up or cracks are generated due to the shearing force. Therefore, a large amount of lubricant is required to reduce the shearing force applied to the molten resin, and if a lubricant such as stearic acid inorganic salt or hydrocarbon wax is mixed in the molten resin, the physical properties of the molded product may be lowered. There is a problem that it is expensive.
Therefore, a method (solidification extrusion method) in which the resin is compressed and cured before defects such as fluffing are generated by a cooling mold directly connected to the extruder may be performed. However, since it is necessary to sufficiently cool the mold, it is necessary to mold at a low speed.

JP 2003-335965 A

  Under such circumstances, an object of the present invention is to provide an industrial production method of an extruded product that is highly rigid, excellent in surface transferability by a shaping mold, and capable of high-speed molding. It is.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention consist of a thermoplastic resin composition containing a thermoplastic resin having a specific melt mass flow rate and a specific content of reinforcing filler. Thus, the present inventors have found that the above-mentioned problems can be achieved, and have reached the present invention based on this finding.

That is, according to the first invention of the present invention, the reinforcing filler (B) is added to the thermoplastic resin (A) having a melt mass flow rate of 0.2 to 30 g / 10 min. %, A method for producing an extruded product obtained by extruding a thermoplastic resin composition blended at a ratio of
Under the shaping die of the extruder, the relationship between the apparent viscosity (ηa) (Pa · s) of the resin composition and the shear rate (γ) (s ⁻¹ ) of the extruder satisfies the following formula: Control the temperature condition of the mold ,
At least a part of the thermoplastic resin (A) is polyolefin and polystyrene,
Method for manufacturing extrusion molded body reinforcing filler (B) is characterized by fly ash der Rukoto is provided.
ηa = α × γ ⁿ
ηa: Apparent viscosity (Pa · s)
α: coefficient γ: shear rate (s ⁻¹ )
n: Coefficient (wherein the coefficient α is 30,000 to 350,000, and the coefficient n is −0.90 to −0.55).

  Further, according to the second invention of the present invention, in the first invention, when the thermoplastic resin composition is melted and passed through a shaping mold directly connected to an extruder, it is passed through a sizing cooling mold. In addition, the extrusion molded body is characterized in that the temperature of the resin composition surface layer portion immediately after passing through the shaping mold is set higher than the resin composition temperature immediately before passing through the shaping die. A manufacturing method is provided.

  According to a third aspect of the present invention, there is provided a method for producing an extruded molded body according to the first or second aspect, wherein the extrusion linear velocity of the extruded molded body is 1 m / min or more. .

  The production method of the present invention uses a thermoplastic resin composition obtained by blending a large amount of a reinforcing filler (B) with a thermoplastic resin (A), is highly rigid, and has excellent surface transferability by a shaping mold. Further, there is an advantage that an extruded product excellent in appearance can be produced with high productivity.

The schematic diagram of an example of the shaping | molding apparatus used for the manufacturing method of this invention.

The extruded product of the present invention uses a thermoplastic resin composition obtained by blending a specific content of reinforcing filler (B) with a thermoplastic resin (A) having a specific melt mass flow rate, and this is extruded. It consists of.
Hereinafter, the structure, manufacturing method, and the like of the extruded product of the present invention will be described in detail.

  1. Extruded body structure

<Thermoplastic resin>
It is important that the thermoplastic resin used as the component (A) in the thermoplastic resin composition has a melt mass flow rate of 0.2 to 30 g / 10 min, and is not particularly limited as long as it is satisfied. For example, polyolefin, polystyrene Polyamide such as polyvinyl chloride and nylon, ABS, EVA, polyester such as polyethylene terephthalate and polybutylene terephthalate, acrylic resin, fluororesin, polyurethane, polycarbonate, polyphenylene oxide, polyphenylene sulfide, polyacetal and the like. Specific examples of polyolefins include polyethylene such as LLDPE (linear low density polyethylene), HDPE (high density polyethylene), and LDPE (low density polyethylene), polypropylene, propylene / ethylene block copolymer, propylene / ethylene random copolymer. Examples thereof include a copolymer, a propylene / α-olefin block copolymer, and a propylene / α-olefin random copolymer.
These may be used alone or in combination of two or more.
Since the polystyrene resin has a high elastic modulus, the rigidity can be improved by the thermoplastic resin mixed therewith.
As the thermoplastic resin, polyolefin is particularly preferable because it is easy to obtain interfacial adhesion to the reinforcing filler by means such as acid modification described later, and it is not decomposed by shear heat generated by the reinforcing filler and screw. In addition, polyethylene or a mixture of polyolefin and polystyrene is preferable.
The thermoplastic resin may not be a virgin product, and may be a container / packaging recycling material.
Containers and packaging recycling materials are containers and packaging materials that are discharged and collected from homes, etc., and mainly contain polyethylene, polypropylene, and polystyrene, and preferably have a melt mass flow rate of 4 to 10 (g / 10 min) It is. This container / packaging recycle material contains at least 20% by weight of polypropylene, 30 to 70% by weight of polyethylene, and 3 to 30% by weight of polystyrene. Polystyrene has high rigidity, and rigidity is easily obtained by being dispersed in polyolefin.

As the thermoplastic resin, in order to further improve the interfacial adhesion between the reinforcing resin and the reinforcing filler and to obtain a further elastic modulus improving effect, at least a part of the thermoplastic resin is acid-modified with an unsaturated carboxylic acid. preferable. As the unsaturated carboxylic acid, maleic anhydride is preferred.
From the viewpoint of cost effectiveness, the acid modification degree of the thermoplastic resin is preferably 0.02 to 0.5%, and more preferably 0.15 to 0.3%.

  If the melt mass flow rate of the thermoplastic resin is smaller than 0.2 (g / 10 min), sufficient adhesion between the reinforcing filler and the thermoplastic resin cannot be obtained, rigidity is hardly exhibited, and 30 ( Even if it is larger than g / 10 min), the viscosity of the thermoplastic resin composition with reinforcing filler mixed therein is too low to cause drawdown at the time of extrusion molding, so that it is necessary to perform low-speed molding by solidification extrusion or the like.

<Reinforcing filler>
Further, the reinforcing filler used together with the resin component as the component (B) in the resin composition of the present invention is not particularly limited, but is preferably a fibrous, granular or powdery organic / inorganic substance, and is fibrous. Glass fiber, alumina fiber, silicon carbide fiber, ceramic fiber, asbestos fiber, gypsum fiber, stainless steel fiber, boron fiber, carbon fiber, polyparaphenylene terephthalamide fiber (for example, DuPont Kevlar), etc. As granular or powdery, coal ash represented by fly ash; silicates such as wollastonite, barite, mica, sericite, kaolin, clay, bentonite, talc, calcium silicate, silica sand, alumina silicate; Alumina, silica, magnesium oxide, zirconium oxide, titanium oxide Oxides such as: carbonates such as calcium carbonate, magnesium carbonate, dolomite; sulfates such as calcium sulfate, gypsum, barium sulfate; other glass beads, glass flakes, glass granules, boron nitride, silicon carbide, cement concrete grinding Materials, rock granule, vermiculite, pearlite, expanded shale, etc., preferably inorganic substances, especially coal ash, especially fly ash, is discharged in large quantities as a by-product from thermal power plants, is cheap and readily available, and the environment Recommended in terms of conservation and waste recycling. Further, since fly ash is spherical, the flow rate of the resin is stable in the extruder, and the shape is not easily changed by shearing by kneading with a screw or the like.
These may be used alone or in combination of two or more.
The reinforcing filler is preferably in the form of particles because the particle size distribution is large and it is easy to pack finely, and the average particle size of such particles is preferably 1 to 1000 μm, more preferably 10 to 300 μm. If this particle size is too small, it will be difficult to disperse uniformly in the thermoplastic resin, and if it is too large, it will be difficult to obtain a thin molded product, and external force will be applied to the molded product. In particular, stress concentration tends to occur at the interface between the reinforcing filler and the thermoplastic resin.

  In the thermoplastic resin composition, the reinforcing filler is contained in a proportion of 35% by volume or more and 80% by volume or less, preferably 40 to 75% by volume, more preferably 45 to 70% by volume with respect to the total amount of the thermoplastic resin composition. It is important. If this content is less than 35% by volume, the apparent viscosity of the thermoplastic resin composition cannot be sufficiently improved, and a desired reinforcing effect cannot be obtained. Moreover, when it exceeds 80 volume%, it becomes difficult for a thermoplastic resin to enter between reinforcement fillers, and it is easy to produce a surface property defect.

  The thermoplastic resin composition further comprises a plasticizer for improving moldability, a lubricant for improving moldability, an ultraviolet absorber for improving durability such as weather resistance, and ultraviolet degradation, if necessary. Improves the affinity between anti-oxidants, anti-oxidation degradation agents, pigments for imparting design, wood texture, grain texture, flame retardants for imparting flame retardancy, etc., thermoplastic resins and reinforcing fillers It may contain known additives such as acid-modified olefins.

  The plasticizer is not particularly limited, and examples thereof include phthalic acid esters and low molecular weight olefins. The lubricant is not particularly limited, and examples thereof include higher fatty acids such as stearic acid and higher fatty acid salts such as metal stearate.

2. Method for Producing Extruded Molded Body Preferably, the method for producing the above extruded molded body is such that, when the thermoplastic resin composition is extruded, the apparent viscosity (ηa) (Pa) of the resin composition under the shaping mold of the extruder. -The method of controlling the temperature conditions of this metal mold | die so that the relationship between s) and the shear rate ((gamma)) (s ^<-1 >) of an extruder may satisfy | fill the following numerical formula is mentioned.
ηa = α × γ ⁿ
ηa: Apparent viscosity (Pa · s)
α: coefficient γ: shear rate (s ⁻¹ )
n: Coefficient (wherein the coefficient α is 30,000 to 350,000, and the coefficient n is −0.90 to −0.55).
The above formula shows the change in apparent viscosity when the shear rate at a certain temperature is changed. The shear rate and the apparent viscosity are each plotted on the XY axis in logarithmic form and approximated by the least square method. Where n is the apparent viscosity (ηa) when the shear rate (γ) is 1, and α.
In said formula, coefficient (alpha) becomes like this. Preferably it is 50000-150,000, More preferably, it is 90000-110000.
The coefficient n is a negative value as described above, and when the shear rate is increased, the apparent viscosity is decreased, preferably −0.75 to −0.55, more preferably −0.70 to −0. The apparent viscosity is less affected by the shear rate and is less susceptible to fluctuations depending on the amount of extrusion.
Further, there is a positive correlation between the shear rate and the extrusion amount, and when the extrusion amount is increased (high speed molding), the apparent viscosity is lowered.

  Further, after the thermoplastic resin composition is melted and passed through a shaping mold directly connected to an extruder, when passing through a sizing cooling mold, the resin composition temperature immediately before passing through the shaping mold On the other hand, it is preferable to set the temperature of the resin composition surface layer portion immediately after passing through the shaping mold to be high. In this way, even a material highly filled with the reinforcing filler can be molded by a method other than the solidification extrusion method.

When the thermoplastic resin is filled with the reinforcing filler, the elongation at break of the resin at the time of melting becomes small, which causes a defect that the surface is rolled up or cracks are generated. The present invention eliminates surface defects by making the apparent viscosity of raw materials under the temperature conditions of a shaping mold within the above range in a thermoplastic resin composition as a thermoplastic resin molding material mixed with reinforcing filler. It is possible to mold at high speed. When the resin composition passes through the mold, frictional resistance is generated. In addition, when the apparent viscosity is lower than the range of the above formula, the flow rate of the resin composition in the extrusion mold is not stable, and the flow rate of the resin composition is increased at the center of the extrusion cross section. For this reason, a defect that causes the surface to be damaged occurs. Further, when the apparent viscosity is higher than the range of the above formula, the shear stress applied to the resin composition tends to be oriented in the direction perpendicular to the extrusion direction, so that the frictional resistance increases, the extrusion amount is not stable, and the surface Prone to cracking. When the apparent viscosity is within the range of the above formula, the stress applied to the resin composition is suitably dispersed, so that molding can be performed at high speed.
In order to adjust the apparent viscosity, the melt mass flow rate of the thermoplastic resin used and the filling amount of the reinforcing filler may be adjusted. Increasing the amount of reinforcing filler increases the apparent viscosity, and decreasing it decreases the apparent viscosity. Further, the apparent viscosity decreases as the melt mass flow rate increases, and increases as it decreases.

  Moreover, in these methods, it is preferable that the extrusion linear velocity of the extrusion-molded body is a high speed of 1 m / min or more.

  In this way, the molding apparatus used for producing the extruded product is formed by connecting an extruder, a cooling mold, a cooling medium tank, and a take-up machine, an example of which is schematically shown in FIG. The extruder 1 is provided with a screw 13 driven by a motor 12 in a cylinder 11, and directly from the hopper 14 as individual raw materials, that is, thermoplastic resin, reinforcing filler, etc., or by previously kneading them. The prepared pellets are supplied, melted and kneaded in a cylinder 11 heated by a drive screw, extruded into an shaping mold 2 through an adapter 15, passed through a cooling mold 3, and further cooled by a cooling water tank 4 and pulled. It is configured to be received by the take-up machine 5 and molded into a desired shape.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by this example. Examples 1 to 5 and 7 to 9 are reference examples.

Examples 1-9, Comparative Examples 1-3
Using the molding apparatus shown in FIG. 1, fly ash (produced by Hokuriku Electric Power Tsuruga Thermal Power Station, average particle size: 14.5 μm) and the thermoplastic resin shown in Table 1 are charged into the extruder at the ratio shown in Table 1 and molded. A flat plate-shaped body having a cross section of 60 mm × 6 mm was prepared as a test piece.
The maximum linear velocity until surface roughness occurred during molding was measured. At that time, the temperature of the shaping mold was set to 180 ° C., and the temperature of the resin composition immediately before passing through the shaping mold and the surface temperature of the resin composition immediately after passing through the mold were measured with a thermocouple.
Moreover, the test piece was cut out from each sample and the tensile elasticity modulus was measured.
In addition, the relationship between the shear rate at 180 ° C. and the apparent viscosity was measured by a capillograph. A cumulative approximation of the relationship between the two.
The melt mass flow rate of the thermoplastic resin was measured according to JIS K 7210, and the container / packaging recycled material was measured according to the standard of polyethylene.
As the maleic anhydride-modified polypropylene, Umex 1010 (trade name, manufactured by Sanyo Kasei Co., Ltd.) was used.
The results are shown in Tables 1 and 2.

  In these tables, PP represents polypropylene, PE represents polyethylene, and PS represents polystyrene.

  Thus, in the comparative example, extrusion molding is impossible, or even if extrusion molding is possible, the elastic modulus of the molded body is low and the rigidity is inferior. I understand that I can do it.

  INDUSTRIAL APPLICABILITY The present invention is highly industrially useful because it can produce an extruded product that has high rigidity, is excellent in surface transferability by a shaping mold, and can be molded at high speed.

1 Extruder 11 Cylinder 12 Motor 13 Screw 14 Hopper 15 Adapter 2 Shaping Mold 3 Cooling Mold 4 Cooling Water Tank 5 Take-up Machine

Claims (3)

A thermoplastic resin composition comprising a thermoplastic filler (A) having a melt mass flow rate of 0.2 to 30 g / 10 min and a reinforcing filler (B) blended in a proportion of 35 to 80% by volume based on the total amount of the composition. A method for producing an extruded product obtained by extrusion molding,
Under the shaping die of the extruder, the relationship between the apparent viscosity (ηa) (Pa · s) of the resin composition and the shear rate (γ) (s ⁻¹ ) of the extruder satisfies the following formula: Control the temperature condition of the mold ,
At least a part of the thermoplastic resin (A) is polyolefin and polystyrene,
Method for manufacturing extrusion molded body reinforcing filler (B) is characterized by fly ash der Rukoto.
ηa = α × γ ⁿ
ηa: Apparent viscosity (Pa · s)
α: coefficient γ: shear rate (s ⁻¹ )
n: Coefficient (wherein the coefficient α is 30,000 to 350,000, and the coefficient n is −0.90 to −0.55).   When the thermoplastic resin composition is melted and passed through a shaping mold directly connected to an extruder, and then passed through a sizing cooling mold, the resin composition temperature immediately before being passed through the shaping mold The method for producing an extrusion-molded article according to claim 1, wherein the temperature of the resin composition surface layer portion immediately after passing through the shaping mold is set to be high. The method for producing an extruded product according to claim 1 or 2, wherein an extrusion linear velocity of the extruded product is 1 m / min or more.

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