JP2001096603A - Manufacturing apparatus and manufacturing method of thermoplastic resin molded article - Google Patents

Abstract

(57) [Problem] To use a thermoplastic resin composition containing a large amount of filler as a raw material, and to perform extrusion molding that simultaneously satisfies avoidance of excessive shear heat generation and prevention of leakage of high-pressure gas. Provided are a manufacturing apparatus and a manufacturing method of a thermoplastic resin molded body that can be manufactured. A first upstream side of a portion for supplying a high-pressure gas is provided.
When the shape of the screw 112 in the stage 1A is “the volume per unit length of the first supply unit 1a ÷ the first measurement unit 1c”
Has a compression ratio defined by “volume per unit length of 1.0 = 1.8 to 1.8”, and “the diameter of the groove of the first measuring portion 1c ÷ the first diameter”.
This is an apparatus for manufacturing a thermoplastic resin molded article having a shape in which the first measuring portion 1c has a groove diameter defined by "the cylinder inner diameter of the measuring portion = 0.85 or less".

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for producing a thermoplastic resin molded article.

[0002]

2. Description of the Related Art In forming a resin foam by injecting a liquid or gaseous foaming agent into a thermoplastic resin composition supplied into an extruder and extruding the same from a mold attached to the tip of the extruder, As a method for preventing the leakage of the blowing agent to the upstream side of the extruder, for example, as described in Japanese Patent Publication No. 42817/1989, a screw of the extruder is provided with a conical pressing portion and a closing portion, and It has been proposed to make the resin denser.

[0003] However, in the case of this method, when applied to a thermoplastic resin composition containing a large amount of filler, the thermoplastic resin composition having a high viscosity due to a large amount of filler has a large conical compression portion. Shear occurs,
Because excessive heat is likely to be generated, control of the resin temperature becomes extremely difficult due to this heat generation, and in the case of a thermoplastic resin composition containing a thermally decomposable resin or a compounding agent, the quality of the product is severely degraded. If it is more pronounced, there is a problem that extrusion molding becomes impossible.

It is known that the viscosity of a thermoplastic resin composition can be reduced by impregnating a high-pressure gas into the thermoplastic resin composition. However, in the method described in Japanese Patent Publication No. 42817/1990, the above-described effect of lowering the viscosity is not exhibited in the upstream portion before the gas is supplied. For this reason, as described above, in the case of a thermoplastic resin composition containing a large amount of a filler, the heat generated by shearing is liable to be excessively generated due to extremely high viscosity.

[0005] For the above reasons, the shape of the screw before the gas is supplied must be very careful.
When a commonly used single screw having a compression ratio of 2 to 3 is used, it is difficult to avoid severe shear heat generation in a thermoplastic resin composition containing a large amount of filler.

However, according to the method described in Japanese Patent Publication No. 1-42817, the screw shape before gas is supplied into the thermoplastic resin composition is not specifically designed for compression ratio, groove depth, pitch and the like. Therefore, it is practically impossible to extrude a thermoplastic resin composition containing a large amount of filler while simultaneously avoiding excessive shear heat generation and preventing high pressure gas leakage. It is.

When a material having a low bulk specific gravity (about 0.1 to 0.3 g / cm ³ ), such as wood powder, is used as a filler, the material generally has a flight pitch equivalent to the screw outer diameter. In the single screw, the amount of the raw material per revolution in the supply section immediately after the hopper becomes extremely small, and it is difficult to secure a required amount of extrusion per hour.

[0008] Of course, it is possible to increase the extrusion amount by increasing the number of revolutions, but it is not preferable because the increase in the number of revolutions increases the heat generated by shearing in the metering section of the screw before gas supply. Although it is possible to increase the amount of extrusion by increasing the groove depth of the supply section immediately after the hopper,
Since the diameter of the screw groove portion becomes small, it is impossible to set the groove depth too large due to the strength of the screw in a thermoplastic resin composition containing a large amount of a filler that easily applies a large torque to extrusion.

Further, in the above-mentioned conventional method, it is impossible to change the shape of the conical pressing portion while operating the extruder. For this reason, it is difficult to cope with changes in the extrusion conditions such as changes in the resin composition and the filling rate, changes in the screw rotation speed and the amount of extrusion, etc., while simultaneously avoiding the heat generation of the resin and the leakage of the high pressure gas. is there.

[0010]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and can avoid excessive shear heat generation even if a thermoplastic resin composition containing a large amount of filler is used as a raw material. It is an object of the present invention to provide a manufacturing apparatus and a manufacturing method of a thermoplastic resin molded article capable of performing extrusion molding that simultaneously prevents leakage of high-pressure gas.

[0011]

According to the first aspect of the present invention, an extruder in which a screw is disposed in a cylinder is connected to an upstream side of the extruder. A hopper for supplying a thermoplastic resin composition, a device for supplying a high-pressure gas connected in the middle of the cylinder, and a device for manufacturing a thermoplastic resin molded body including a mold connected downstream of the extruder Wherein the screw is
A first stage upstream of a portion for supplying high-pressure gas;
The first stage is divided into a second stage on the downstream side that supplies a high-pressure gas and kneads with the thermoplastic resin composition, wherein the first stage transports a fixed amount of the thermoplastic resin composition supplied from the hopper, The thermoplastic resin composition continuously moves substantially impermeable to a first compression section for compressing and densifying the thermoplastic resin composition and a high-pressure gas supplied to a second supply section of a second stage later. A first metering unit that forms a barrier with the compressed and densified thermoplastic resin composition, wherein the second stage includes a second supply unit that supplies a high-pressure gas, and the thermoplastic resin composition And a high-pressure gas are kneaded, a second compression unit for compressing, and a second measurement unit for measuring a mixture of the thermoplastic resin composition and the high-pressure gas, and the shape of the screw in the first stage is "Volume per unit length of the first supply unit It has a compression ratio which is defined by the unit volume = 1.0 to 1.8 per length "of the first metering section," first
Diameter of groove of measuring section / inner diameter of cylinder of first measuring section =
This is a manufacturing apparatus for a thermoplastic resin molded article in which the first measuring portion has a groove diameter defined by “0.85 or less”.

The invention described in claim 2 of the present application (the present invention 2)
Is the shape of the screw in the first stage,
The present invention 1 has a flight pitch defined by “flight pitch of first supply unit ÷ cylinder diameter of first supply unit = 1.5 to 3.0”, and the first supply unit has two or more flights. It is a manufacturing apparatus of the thermoplastic resin molding according to the above.

The invention described in claim 3 of the present application (the present invention 3)
Are provided with a screw in each cylinder, a first-stage extruder and a second-stage extruder connected in series, and a thermoplastic resin connected upstream of the first-stage extruder. A hopper for supplying the resin composition, a high-pressure gas supply device connected near a connection between the first-stage extruder and the second-stage extruder, and a downstream side of the second-stage extruder. A manufacturing apparatus for a thermoplastic resin molded article including a connected mold, wherein a screw of the first-stage extruder is configured to transport a thermoplastic resin composition supplied from the hopper in a first supply section. A first compression section for compressing and densifying the thermoplastic resin composition; and a high-pressure gas supplied to a second supply section of a second stage later, continuously substantially impermeable to high pressure gas. The moving barrier is compressed and densified in the thermoplastic resin composition. A first metering section formed by the second step, wherein the screw of the second-stage extruder has a second supply section for supplying high-pressure gas, and a second supply section for kneading and compressing the thermoplastic resin composition and high-pressure gas. A compression section, and a second measurement section for measuring a mixture of the thermoplastic resin composition and the high-pressure gas, wherein a shape of a screw in the first-stage extruder is “unit length of the first supply section”. Volume per area / 1st
It has a compression ratio defined by “volume per unit length of measuring section = 1.0 to 1.8”, and “diameter of groove section of first measuring section / cylinder inner diameter of first measuring section = 0.85 or less” "A manufacturing apparatus for a thermoplastic resin molded article having a shape in which the first measuring portion has a groove diameter defined by"".

The invention described in claim 4 of the present application (Invention 4)
The shape of the screw in the first-stage extruder has a flight pitch defined by “flight pitch of first supply unit ÷ cylinder diameter of first supply unit = 1.5 to 3.0”, The flight of the first supply unit is a thermoplastic resin molded article manufacturing apparatus according to the third aspect of the present invention, which has two or more flights.

The invention according to claim 5 of the present application (the present invention 5)
Uses the apparatus for manufacturing a thermoplastic resin article according to the first or second aspect of the present invention, and the thermoplastic resin 10
A thermoplastic resin composition containing 50 to 1000 parts by weight of a filler is supplied to 0 parts by weight, and the mixture is passed through the first stage, and a high-pressure gas is supplied in the second stage to form a thermoplastic resin composition. This is a method for producing a thermoplastic resin molded article, which comprises kneading and continuously extruding a thermoplastic resin molded article from the mold.

The invention according to claim 6 of the present application (the present invention 6)
Using the apparatus for producing a thermoplastic resin molded article according to the present invention 3 or 4, and the thermoplastic resin 10
A thermoplastic resin composition containing 50 to 1000 parts by weight of a filler is supplied to 0 parts by weight and passed through a first-stage extruder, and a first-stage extruder and a second-stage extruder are used. A high pressure gas is supplied in the vicinity of the connecting portion of the above to knead with the thermoplastic resin composition, and the thermoplastic resin molded body is continuously extruded from the mold to produce a thermoplastic resin molded body.

The invention according to claim 7 of the present application (the present invention 7)
Is that the thermoplastic resin composition is "bulk specific gravity before feeding to the extruder / specific gravity in the solid state of the thermoplastic resin molded body =
A method for producing a thermoplastic resin molded article according to the present invention 5 or 6, which has a density defined by "0.5 or less".

In the present invention, as the extruder, a single-screw or two-screw or more is used. In the case of a twin-screw, the screw may be rotated in the same direction or in the opposite direction. May be a parallel type or a conical type, or may be a tandem type in which extruders are combined in multiple stages.

In the present invention, the gas forming the high-pressure gas is an organic or inorganic substance which is in a gaseous state at normal temperature and normal pressure, and has a good impregnating property at a high temperature and a high pressure without deteriorating the resin. If there is, it can be used without particular limitation. Since the gas is in a gaseous state at normal temperature and normal pressure, it can be easily removed from the resin after use. Also, fire,
A gas that does not have a danger of explosion or the like, is safe for the environment and the health of workers, and is easily collected is preferable.

Examples of such gases include inorganic gases such as carbon dioxide, nitrogen, argon, neon, helium, and oxygen, and organic gases such as chlorofluorocarbon and low molecular weight hydrocarbons. Impregnation is preferably selected. The gas is preferably in a supercritical state where the impregnation rate is high. The supercritical state is the critical temperature,
It refers to a state above the critical pressure. For example, when the gas is carbon dioxide gas, the critical temperature is 30.9 ° C., the critical pressure is 7.4 MPa, and when the gas is nitrogen gas, the critical temperature is −14.
At 6.9 ° C., the critical pressure is 3.4 MPa.

The amount of gas impregnated in the thermoplastic resin is as follows:
Any amount may be used as long as the melt viscosity of the resin can be reduced by a required amount, and can be appropriately selected depending on the type of the resin and the type of the gas. However, 3 to 50 parts by weight of the gas is impregnated with respect to 100 parts by weight of the thermoplastic resin. Preferably. Also, gas impregnation is most preferably in a saturated state, but need not necessarily be achieved.

In the present invention, the thermoplastic resin in the thermoplastic resin composition is not particularly limited.
Polyethylene, polypropylene, polyolefin such as ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, acrylonitrile-styrene-butadiene copolymer, acrylonitrile-styrene copolymer, polystyrene, methallyl resin, polyamide, polycarbonate, polyacetal, Polyester, acrylic resin,
Thermoplastic elastomer, powder rubber and the like can be mentioned. These may be used alone or in combination. Further, a modified or crosslinked resin may be used as long as the object of the present invention is not impaired.

In the present invention, the filler in the thermoplastic resin composition is not particularly limited. For example, mica, silica, talc, stone powder, diatomaceous earth, clay, graphite, carbon black, calcium carbonate, titanium oxide, alumina , Aluminum powder, iron powder, molybdenum disulfide, barium sulfate, lithium soap, wood powder, glass,
Pulp and the like. These may be used alone or in combination.

The amount of the filler added is selected from thermoplastic resin 1
50 to 1000 parts by weight is preferable with respect to 00 parts by weight. If the amount is less than 50 parts by weight, ordinary extrusion molding can be performed with such a small amount in many cases. Therefore, the necessity of applying the present invention is low. If the amount exceeds 1000 parts by weight, the viscosity of the composition is significantly increased. Or the resulting product may be too brittle to maintain its shape.

In the present invention, additives such as a lubricant, a stabilizer, an anti-blocking agent, an antifoaming agent, a pigment, a dye and the like are added to the thermoplastic resin composition in addition to the thermoplastic resin and the filler. It may be blended to the extent that the purpose is not impaired.
Although a plasticizer and a solvent may be similarly blended, it is preferable not to use it from the viewpoint of environment and safety.

In the present invention 1 and the present invention 3, "the continuously moving barrier substantially impermeable to the supplied high-pressure gas is formed by the compressed and densified thermoplastic resin composition. "Form" means that the thermoplastic resin composition is compressed by a screw transporting capability to a density of a solid body (unfoamed molded body) or a density close to the solid body, and a high-pressure gas as a foaming agent flows backward, This refers to sealing so as not to leak, and the compressed thermoplastic resin composition is continuously replaced by the thermoplastic resin composition sequentially supplied from the inlet of the raw material moving downstream by the screw.

Here, the compression ratio is the volume ratio between the first supply section and the first measuring section of the screw, that is, the volume per unit length of the first supply section / the unit length of the first measuring section. , And can be calculated from the screw outer diameter and the screw groove diameter. In the present invention, the compression ratio =
It needs to be 1.0 to 1.8. When the compression ratio exceeds 1.8, it becomes close to the compression ratio of a general screw,
Since the groove depth of the measuring section becomes shallow, it is difficult to avoid shear heat generation. If the compression ratio is less than 1.0, it becomes difficult to stably compress the thermoplastic resin composition and seal it against gas. Note that the most preferable compression ratio cannot be strictly defined because it depends on the composition of the thermoplastic resin composition to be used and the amount of the filler added, but if the gas can be sealed, the smaller the compression ratio, the lower the shear heat generation. Can be suppressed.

In the present invention 1 and the present invention 3, when the groove depth of the first measuring portion exceeds “the diameter of the groove portion of the first measuring portion ÷ the inner diameter of the cylinder of the first measuring portion = 0.85”, it is general. And it becomes difficult to avoid shear heat generation. Note that the preferable groove depth cannot be strictly defined because it depends on the composition and the filling amount of the thermoplastic resin composition to be used. However, if gas sealing is possible, “the diameter of the groove portion of the first measuring portion ÷ the first measuring portion” The smaller the cylinder inner diameter, the more the shear heat generation can be suppressed.

In the present invention 1 and the present invention 3, the first
The supply section and the first measuring section are basically based on the fact that the groove depth at the section is constant, but may be changed continuously as long as the object of the present invention is not impaired. In extreme cases, the first
The scope of the present invention is also applicable to a case where the diameter of the groove of the screw continuously increases in the stage or the first-stage extruder, and the regions of the first supply unit, the first compression unit, and the first calculation unit cannot be clearly distinguished. include. In this case, in the first stage or the first-stage extruder, a portion having the smallest groove diameter is considered as the first supply portion, and a portion having the largest groove diameter is considered as the first measuring portion.

In the present invention 2 and the present invention 4, the flight pitch refers to an interval between flights adjacent in the axial direction on the same spiral, and is expressed as “flight pitch of the first supply unit ÷ cylinder diameter of the first supply unit = It is necessary to have a flight pitch defined by "1.5 to 3.0", and if it is less than 1.5, a thermoplastic resin composition having a low bulk specific gravity which is equivalent to a commonly used screw and having a low bulk specific gravity is used. When it exceeds 3.0, it becomes difficult to transport the thermoplastic resin composition stably.

In the present invention 2 and the present invention 4, since the flight pitch of the first supply section of the screw is increased, the first supply section is reliably transferred from the first supply section to the first measurement section without impairing the stability of extrusion. In order to transport the thermoplastic resin composition, it is necessary that the number of strips be 2 or more. Further, the screw shape of the first measuring section is preferably different from that of the first supplying section in order to surely transport the thermoplastic resin composition which has been compressed and increased in density in the first measuring section, It is desirable that the pitch is smaller than that of the first supply section, and as a result, the pitch is one.

The flight pitch may be continuously changed toward the downstream area after the first supply section.
In such a case, it is difficult to clearly distinguish the first supply unit, the first compression unit, and the first measurement unit, but the most upstream position and the most downstream position in the first stage or the first stage extruder. What is necessary is just to consider the flight pitch ratio at the position. In such a case, the number of strips is within the scope of the present invention as long as it is at least two in the first stage or first stage extruder.

In the present invention 3, the first-stage extruder and the second extruder
The connection part of the first-stage extruder is not particularly limited, but the distance between the most downstream position of the screw of the first-stage extruder and the top of the flight part of the screw of the second-stage extruder is several meters.
m or the distance may be set by using a connecting conduit. Further, the connection portion may be provided with a mixing device such as a static mixer, a choke bar, a breaker, or the like that has resistance to the flow of the resin. In the present invention 3, the high-pressure gas supply device may be connected to the most downstream side of the cylinder of the first-stage extruder, or may be connected to the most upstream side of the cylinder of the second-stage extruder. If a connecting conduit is used, it may be connected to the connecting conduit, or may be connected to the vicinity of the connection between the first-stage extruder and the second-stage extruder.

In the present invention 7, it is necessary that the bulk specific gravity of the thermoplastic resin composition before being supplied to the extruder ÷ the specific gravity of the thermoplastic resin molded article in a solid state = 0.5 or less. When the bulk specific gravity exceeds 0.5, there is little problem that the amount of the raw material per rotation is small and the required amount of extrusion per hour cannot be secured. In addition, the bulk specific gravity referred to here is:
This includes a state where the thermoplastic resin composition is naturally dropped by gravity, and a state where the raw material such as a push-in feeder is mechanically compressed and forcedly supplied into an extruder to a relatively high density state.

[0035]

The apparatus for producing a thermoplastic resin molded article of the present invention 1
The shape of the screw in the first stage on the upstream side of the portion for supplying the high-pressure gas is “the volume per unit length of the first supply unit ÷ the volume per unit length of the first measurement unit = 1.0”.
By having a compression ratio defined by "1.8", a continuously moving barrier substantially impervious to the high-pressure gas can be formed by the thermoplastic resin composition. And the shape of the screw in the first stage is “the diameter of the groove of the first measuring section ÷ the inner diameter of the cylinder of the first measuring section = 0.85 or less”
Since the first measuring portion has the groove diameter defined by the formula, excessive shear heat generation can be avoided even in a thermoplastic resin composition containing a large amount of filler. When the screw shape of the first stage has a small compression ratio, the mixing action of the thermoplastic resin composition in the first stage is reduced, but in the subsequent second stage, the resin is impregnated with a high-pressure gas. There is no problem because kneading is possible after the viscosity has been reduced.

[0036] In the apparatus for producing a thermoplastic resin molded article according to the second aspect of the present invention, the shape of the screw in the first stage may be:
It has a flight pitch defined by “flight pitch of the first supply unit ÷ cylinder diameter of the first supply unit = 1.5 to 3.0”, and the number of flights of the first supply unit is two or more. In addition to the effect of the first aspect, the necessary transport capacity can be secured even at a relatively low rotation.

In the apparatus for manufacturing a thermoplastic resin article according to the third aspect of the present invention, the shape of the screw in the first-stage extruder upstream of the portion for supplying the high-pressure gas may be such that: It has a compression ratio defined by “volume / volume per unit length of first measuring section = 1.0 to 1.8”,
Diameter of groove of measuring section / inner diameter of cylinder of first measuring section =
0.81 or less ", the first measuring portion has a shape having a groove diameter defined by" 0.85 or less ". Rotation speed can be set independently of each other, so that the conditions (temperature,
Pressure, the amount of transport), the filling state of the thermoplastic resin composition at the part where the high-pressure gas is injected, and the conditions of the thermoplastic resin composition after the high-pressure gas is injected. It is possible to determine the optimal extrusion conditions for the filling amount and the amount, and to change the conditions while operating, thereby realizing a wide operation range and versatility.

In the apparatus for manufacturing a thermoplastic resin article of the fourth aspect of the present invention, the shape of the screw in the first-stage extruder is such that “flight pitch of the first supply unit ÷ cylinder diameter of the first supply unit = 1.5. 3.0 ", and the number of flights of the first supply unit is two or more, so that in addition to the function of the present invention 3, the necessary transport capacity is secured even at relatively low rotation. be able to.

The method for producing a thermoplastic resin molded article according to the fifth aspect of the present invention uses the apparatus for producing a thermoplastic resin molded article according to the first or second aspect of the present invention. A thermoplastic resin composition containing 50 to 1000 parts by weight of a filler is supplied and passed through the first stage,
In the second stage, a high-pressure gas is supplied and kneaded with the thermoplastic resin composition, and the thermoplastic resin molded body is continuously extruded from the mold to form a thermoplastic resin composition containing a large amount of filler. Even if a material is used, it is possible to extrude a thermoplastic resin molded article while preventing leakage of high-pressure gas and avoiding excessive shear heat generation.

The method for producing a thermoplastic resin molded article according to the sixth aspect of the present invention uses the apparatus for producing a thermoplastic resin molded article according to the third or fourth aspect of the present invention. A thermoplastic resin composition containing 50 to 1000 parts by weight of a filler is supplied and passed through a first-stage extruder, and a high-pressure gas is supplied near a connection between the first-stage extruder and the second-stage extruder. And kneading with the thermoplastic resin composition,
By continuously extruding a thermoplastic resin molded body from the mold, even with a thermoplastic resin composition containing a large amount of filler, while preventing leakage of high-pressure gas,
Extrusion molding of a thermoplastic resin molded article can be performed while avoiding excessive shear heat generation.

The method for producing a thermoplastic resin molded article of the present invention is characterized in that the thermoplastic resin composition is obtained by the following method: "bulk specific gravity before being supplied to an extruder / specific gravity in a solid state of the thermoplastic resin molded article =
By having a density specified by "0.5 or less", extrusion molding capable of stably transporting a thermoplastic composition having a low bulk specific gravity can be performed.

[0042]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view illustrating an example of the apparatus for producing a thermoplastic resin molded article of the present invention.

The apparatus 1 for manufacturing a thermoplastic resin molded article of this example
Is connected to an extruder 11 in which a screw 112 is provided in a cylinder 111, a hopper 12 for supplying a thermoplastic resin composition connected to an upstream side of the extruder 11, and a middle of the cylinder 111. A high-pressure gas supply device 13 and a mold 14 connected to the downstream side of the extruder 11.
Consists of

The screw 112 is divided into a first stage 1A on the upstream side of a portion for supplying the high-pressure gas and a second stage 1B on the downstream side for supplying the high-pressure gas and kneading with the thermoplastic resin composition.

The first stage 1A includes a first supply section 1a for quantitatively transporting the thermoplastic resin composition supplied from the hopper 12, and a first supply section 1a for compressing and densifying the thermoplastic resin composition.
Compression unit 1b and second supply unit 1d of second stage 1B
And a first metering section 1c formed of a compressed and densified thermoplastic resin composition to form a continuously moving barrier that is substantially impermeable to the high-pressure gas supplied to the pressure meter.

The second stage 1B comprises a second supply section 1d for supplying a high-pressure gas, a second compression section 1e for kneading and compressing a thermoplastic resin composition and a high-pressure gas, a thermoplastic resin composition and a high-pressure gas And a second measuring section 1f for measuring the mixture of Screw 112 in first stage 1A
Is “the volume per unit length of the first supply unit 1a ÷
Volume per unit length of first measuring section 1c = 1.0 to 1.
8 ", and" the diameter of the groove of the first measuring part 1c / the inner diameter of the cylinder of the first measuring part 1c = 0.85 "
The first measuring portion has a groove diameter defined by the following.

The shape of the screw 112 in the first stage 1A is determined by the following expression: "flight pitch of the first supply section 1a".
It is desirable that the first supply unit 1a has a flight pitch defined by "cylinder diameter = 1.5 to 3.0", and the number of flights of the first supply unit is two or more.

FIG. 2 is a sectional view for explaining another example of the apparatus for producing a thermoplastic resin molded article of the present invention. The apparatus 2 for manufacturing a thermoplastic resin molded article of this example is connected to the first-stage extruder 2A and the second-stage extruder 2B connected in series, and to the upstream side of the first-stage extruder 2A. A connection portion or 2 between the hopper 22 for supplying the thermoplastic resin composition and the downstream side of the first-stage extruder 2A or the second-stage extruder 2B.
It is composed of a high-pressure gas supply device 23 connected to the upstream side of the second-stage extruder 2B, and a mold 24 connected to the downstream side of the second-stage extruder 2B. In the first-stage extruder 2A,
A screw 2A2 is provided in the cylinder 2A1, and a screw 2B2 is provided in the cylinder 2B1 of the second-stage extruder 2B.

The screw 2A2 of the first-stage extruder 2A
A first supply unit 2a for quantitatively transporting the thermoplastic resin composition supplied from the hopper 22, a first compression unit 2b for compressing and densifying the thermoplastic resin composition, and a second stage 2B to be described later. A continuously moving barrier substantially impermeable to the high-pressure gas supplied to the second supply unit 2d is compressed,
A first measuring section 2c formed of the thermoplastic resin composition having a high density.

The screw 2B2 of the second-stage extruder 2B
Is a second supply section 2d for supplying a high-pressure gas, and a second compression section 2e for kneading and compressing the thermoplastic resin composition and the high-pressure gas.
And a second measuring section 2f for measuring a mixture of the thermoplastic resin composition and the high-pressure gas.

The shape of the screw 2A2 in the first-stage extruder 2A is defined as “the volume per unit length of the first supply unit 2a / the volume per unit length of the first metering unit 2c = 1.0.
-1.8 ", and the" first weighing unit 2 "
The diameter of the groove of c ÷ the inner diameter of the cylinder of the first measuring part 2c =
The first measuring portion has a groove diameter defined by “0.85 or less”.

The shape of the screw 2A2 in the first-stage extruder 2A is “flight pitch of the first supply unit 2a ÷ cylinder diameter of the first supply unit 2a = 1.5 to 3.0”.
It is desirable that the flight of the first supply unit 2a has two or more flights.

(Example) Example 1 A thermoplastic resin molded article was manufactured using the manufacturing apparatus described with reference to FIG. As an extruder, a φ30 single-screw type, L / D = 32, 3.7 kW, screw 112 as shown in Table 1 was used. As the mold, a slit die having a flow path of 30 mm in width × 1 mm in height and capable of controlling the temperature by controlling oil temperature was used.

As a raw material, an ethylene-vinyl acetate copolymer (trade name “Novatech EVA” manufactured by Nippon Polychem Co., Ltd.) was used.
LV660 ") (crushed and used), 100 parts by weight, 200 parts by weight of wood flour (manufactured by Sanwa Cellulosin Co., # 100 mesh, average particle size 28 μm) and a lubricant (manufactured by Kao Corporation, trade name" Kaohax ") 220 ") and 5 parts by weight and mixed in advance (bulk specific gravity; about 0.2 g / cm ³ , specific gravity of a solid body of the molded body; about 1.2 g / cm ³ ), and this is put into a hopper. 12 was supplied.

As a gas, a carbon dioxide gas is used, and is supplied from a high-pressure gas supply device 13 connected to the most upstream portion of the second stage 1B into the thermoplastic resin composition in the second stage 1B. It was supplied at 20 MPa and an average impregnation amount of 10 parts by weight (calculated from the extrusion amount and the gas supply amount).

The molding conditions are as follows. Extrusion molding machine; screw rotation speed is as shown in Table 1, temperature setting is 80 to 120 ° C, resin temperature is as shown in Table 1,
The most downstream pressure was 30-50 MPa. The mold set temperature was 60 to 70 ° C. The extrusion rate was as shown in Table 1.
About the sample extruded from the metal mold, the burnt state was observed. Table 1 shows the results.

Example 2 A sample extruded from a mold was observed for burnt conditions in the same manner as in Example 1 except that the screw 112 used was as shown in Table 1 as an extruder. . Table 1 shows the results.

Comparative Examples 1 and 2 Extrusion molding machines were used in the same manner as in Example 1 except that screws 112 shown in Table 1 were used. Observed. Table 1 shows the results.

[0059]

[Table 1]

As is clear from Table 1, in each of Examples 1 and 2 of the present invention, the obtained samples were free from scorch and the extrusion amount was large, while Comparative Examples 1 and 2 were large. 2
In the case of, there is burnt in all the obtained samples,
The extrusion rate was also small.

Examples 3 and 4 A thermoplastic resin molded article was manufactured using the manufacturing apparatus described with reference to FIG. As the extruder, a tandem type extruder was used. The first-stage extruder 2A is a φ30 single-screw type, with L / D = 22, 2.2 k
w, screws 2A2 as shown in Table 2 were used. The second-stage extruder 2B is a φ70 single-screw type, L / D = 10, 2.2 kw, screw 2B2
However, what consisted of one line, a pitch of 40 mm, and a groove portion of φ50 → 60 was used. As a mold, width 30mm x height 1mm
And a slit die capable of controlling the temperature by oil temperature control. The raw materials and gases were the same as in Example 1.

The molding conditions are as follows. First-stage extruder; screw rotation speed is as shown in Table 2, temperature setting is 80 to 120 ° C., resin temperature is as shown in Table 2, tip pressure is 15 to 25 MPa. Second-stage extruder: Screw rotation speed should be adjusted to 3
10 to 10 rpm, set temperature is 100 to 120 ° C, and tip pressure is 30 to 50 MPa. The mold set temperature is 60 to 70 in Table 2.
° C. The extrusion rate is as shown in Table 2.

The molded product obtained by extrusion molding from the mold was observed for burnt condition. Table 2 shows the results.

Comparative Examples 3 to 5 Samples extruded from a mold were prepared in the same manner as in Examples 3 and 4, except that the screw used as shown in Table 2 was used as the first-stage extruder 2A. And the state of the burn was observed. Table 2 shows the results.

[0065]

[Table 2]

As is clear from Table 1, in each of Examples 3 and 4 of the present invention, the obtained samples were free from scorch and the extruded amount was large. 5
In the case of, there is burnt in all the obtained samples,
The extrusion rate was also small.

[0067]

According to the present invention, the apparatus and method for producing a thermoplastic resin molded article according to the present invention are configured as described above.
Even if a thermoplastic resin composition containing a large amount of filler is used as a raw material, excessive heat generation due to shearing can be avoided, and extrusion molding that prevents leakage to the upstream side even when high-pressure gas is injected can be performed. Yes, this makes it possible to produce a good product without decomposition or burns.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a manufacturing apparatus and a manufacturing method of a thermoplastic resin molded article of the present invention.

FIG. 2 is a cross-sectional view illustrating another example of the apparatus and method for manufacturing a thermoplastic resin molded article of the present invention.

[Explanation of symbols]

 1, 2 Manufacturing device 11 Extruder 12, 22 Hopper 13, 23 High-pressure gas supply device 14, 24 Die 111 Cylinder 112 Screw 1A First stage 1B Second stage 2A First stage extruder 2B Second stage extrusion Molding machines 2A1, 2B1 Cylinders 2A2, 2B2 Screws 1a, 2a First supply unit 1b, 2b First compression unit 1c, 2c First weighing unit 1d, 2d Second supply unit 1e, 2e Second compression unit 1f, 2f Second Weighing section

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F207 AA10 AB02 AG20 KA01 KA11 KF04 KF12 KK23 KL03 KL04 KL15 KL31

Claims (7)

[Claims] An extruder in which a screw is disposed in a cylinder, a hopper connected to an upstream side of the extruder for supplying a thermoplastic resin composition, and a high pressure connected in the middle of the cylinder. An apparatus for producing a thermoplastic resin molded body comprising a gas supply device and a mold connected to a downstream side of the extruder, wherein the screw is a first upstream side of a high pressure gas supply portion. Stage and a second downstream side for supplying high pressure gas and kneading with the thermoplastic resin composition
Divided into stages, the first stage includes a first supply unit that transports the thermoplastic resin composition supplied from the hopper in a fixed amount, and a first compression unit that compresses the thermoplastic resin composition to increase the density. Forming a continuously moving barrier substantially impermeable to the high-pressure gas supplied to the second supply section of the second stage by the compressed and densified thermoplastic resin composition. A second metering section for supplying a high-pressure gas, a second compression section for kneading and compressing the thermoplastic resin composition and the high-pressure gas, A second measuring section for measuring a mixture of the resin composition and the high-pressure gas, wherein the shape of the screw in the first stage is such that “the volume per unit length of the first supply section ÷ the first measuring section; Volume per unit length = 1.
0 to 1.8 ", and" the diameter of the groove of the first measuring portion / the inner diameter of the cylinder of the first measuring portion = 0.85 "
An apparatus for manufacturing a thermoplastic resin article, characterized in that the first measuring part has a groove diameter defined by the following. 2. A shape of a screw in the first stage has a flight pitch defined by “flight pitch of first supply unit ÷ cylinder diameter of first supply unit = 1.5 to 3.0”, The apparatus for producing a thermoplastic resin article according to claim 1, wherein the first supply section has two or more flights. 3. A screw is disposed in each cylinder, and a first-stage extruder and a second-stage extruder connected in series and an upstream side of the first-stage extruder. A hopper for supplying the thermoplastic resin composition, a high-pressure gas supply device connected near a connecting portion between the first-stage extruder and the second-stage extruder, and a hopper for supplying the second-stage extruder. An apparatus for manufacturing a thermoplastic resin molded body comprising a mold connected to a downstream side, wherein a screw of the first-stage extruder is configured to perform quantitative transport of the thermoplastic resin composition supplied from the hopper. 1 supply unit, a first compression unit for compressing and densifying the thermoplastic resin composition, and a high-pressure gas supplied to a second supply unit of a second stage later, which is substantially impermeable to high pressure gas. The continuously moving barrier, compressed, densified thermoplastic A first metering section formed of a resin composition, wherein a screw of the second-stage extruder kneads and compresses the thermoplastic resin composition and the high-pressure gas with a second supply section for supplying a high-pressure gas; And a second measuring section for measuring a mixture of the thermoplastic resin composition and the high-pressure gas, wherein the shape of the screw in the first-stage extruder is a “first supply section”. Volume per unit length / volume per unit length of first weighing unit = 1.0-1.
8 "having a compression ratio defined by" the diameter of the groove of the first measuring portion ÷ the inner diameter of the cylinder of the first measuring portion = 0.85 or less ". An apparatus for manufacturing a thermoplastic resin molded article, characterized in that: 4. The shape of the screw in the first-stage extruder is such that the flight pitch defined by “flight pitch of first supply unit ÷ cylinder diameter of first supply unit = 1.5 to 3.0” is satisfied. 4. The apparatus for producing a thermoplastic resin article according to claim 3, wherein the number of flights of the first supply unit is two or more. 5. 5. The thermoplastic resin molded article manufacturing apparatus according to claim 1 or 2, wherein the hopper is mixed with 50 to 1000 parts by weight of a filler based on 100 parts by weight of the thermoplastic resin. The thermoplastic resin composition is supplied and passed through the first stage, and the high pressure gas is supplied and kneaded with the thermoplastic resin composition in the second stage, and the thermoplastic resin molded body is continuously extruded from the mold. A method for producing a thermoplastic resin article, comprising: molding. 6. The thermoplastic resin molded article manufacturing apparatus according to claim 3 or 4, wherein the hopper is blended with 50 to 1000 parts by weight of a filler based on 100 parts by weight of the thermoplastic resin. The thermoplastic resin composition is supplied and passed through the first-stage extruder, and a high-pressure gas is supplied near the connection between the first-stage extruder and the second-stage extruder to produce the thermoplastic resin composition. And continuously extruding the thermoplastic resin molded article from the mold. 7. The thermoplastic resin composition having a density specified by “bulk specific gravity before being supplied to an extruder 比 specific gravity in a solid state of a thermoplastic resin molded article = 0.5 or less”. The method for producing a thermoplastic resin article according to claim 5 or 6, wherein: