JP2019181788A5

JP2019181788A5 -

Info

Publication number: JP2019181788A5
Application number: JP2018074880A
Authority: JP
Filing date: 2018-04-09
Publication date: 2021-05-20
Anticipated expiration: 2038-04-09

Description

本発明の第１の態様に従えば、発泡成形体の製造方法であって、内部に回転及び進退自在に設けられたスクリュを備え、熱可塑性樹脂が可塑化溶融されて溶融樹脂となる可塑化ゾーンと、前記溶融樹脂が飢餓状態となる飢餓ゾーンとを有し、前記飢餓ゾーンに物理発泡剤を導入するための導入口が形成された可塑化シリンダを含む製造装置を用い、前記製造方法は、前記可塑化ゾーンにおいて、前記熱可塑性樹脂を可塑化溶融して前記溶融樹脂とすることと、前記飢餓ゾーンに、一定の圧力である第１の圧力を有する、前記物理発泡剤を含む加圧流体を導入することと、前記飢餓ゾーンにおいて、前記溶融樹脂を飢餓状態とすることと、前記飢餓ゾーンにおいて、前記飢餓状態の溶融樹脂と、前記第１の圧力の加圧流体とを接触させることと、前記第１の圧力の加圧流体と接触させた前記溶融樹脂を所定量計量することと、前記計量した溶融樹脂を前記可塑化シリンダから射出して、前記発泡成形体に成形することとを含み、前記溶融樹脂の計量の完了まで、スクリュ背圧を前記第１の圧力より高い第２の圧力に保持し、前記溶融樹脂の計量の完了から射出の開始まで、前記スクリュ背圧を前記第２の圧力以上の第３の圧力に保持することを特徴とする発泡成形体の製造方法が提供される。 According to the first aspect of the present invention, it is a method for producing a foamed molded product, which is provided with a screw provided inside so as to be rotatable and retractable, and the thermoplastic resin is plasticized and melted to become a molten resin. The manufacturing method uses a manufacturing apparatus including a plasticized cylinder having a zone and a starvation zone in which the molten resin is starved, and an introduction port for introducing a physical foaming agent into the starvation zone. In the plasticization zone, the thermoplastic resin is plastically melted to obtain the molten resin, and the starvation zone is pressurized with the physical foaming agent having a first pressure which is a constant pressure. Introducing a fluid, starving the molten resin in the starvation zone, and bringing the starved molten resin into contact with the pressurized fluid of the first pressure in the starvation zone. And, the molten resin in contact with the pressurized fluid of the first pressure is weighed in a predetermined amount, and the weighed molten resin is injected from the plasticizing cylinder to be molded into the foam molded body. The screw back pressure is held at a second pressure higher than the first pressure until the measurement of the molten resin is completed, and the screw back pressure is held from the completion of the measurement of the molten resin to the start of injection. Provided is a method for producing a foamed molded article, which comprises holding the foam at a third pressure equal to or higher than the second pressure.

第２の圧力と第３の圧力が同一であってもよい。 The second pressure and the third pressure may be the same.

本発明の第２の態様に従えば、発泡成形体を製造する製造装置であって、内部に回転及び進退自在に設けられたスクリュを備え、熱可塑性樹脂が可塑化溶融されて溶融樹脂となる可塑化ゾーンと、前記溶融樹脂が飢餓状態となる飢餓ゾーンとを有し、前記飢餓ゾーンに物理発泡剤を導入するための導入口が形成され、一定量の前記溶融樹脂を計量して外部に射出する可塑化シリンダと、前記可塑化シリンダに、一定圧力である第１の圧力の物理発泡剤を供給する物理発泡剤供給機構と、前記溶融樹脂の計量の完了まで、スクリュ背圧を前記第１の圧力より高い第２の圧力に保持し、前記溶融樹脂の計量の完了から射出の開始まで、前記スクリュ背圧を前記第２の圧力以上の第３の圧力に保持するように構成された圧力保持機構とを有することを特徴とする製造装置が提供される。 According to the second aspect of the present invention, it is a manufacturing apparatus for manufacturing a foamed molded product, which is provided with a screw provided inside so as to be rotatable and retractable, and the thermoplastic resin is plasticized and melted to become a molten resin. It has a plasticization zone and a starvation zone in which the molten resin is starved, and an introduction port for introducing a physical foaming agent is formed in the starvation zone, and a certain amount of the molten resin is weighed to the outside. The plastic molding cylinder to be injected, the physical foaming agent supply mechanism for supplying the physical foaming agent of the first pressure which is a constant pressure to the plasticized cylinder, and the screw back pressure until the measurement of the molten resin is completed. It is configured to hold at a second pressure higher than the pressure of 1 and hold the screw back pressure at a third pressure higher than the second pressure from the completion of weighing the molten resin to the start of injection. A manufacturing apparatus characterized by having a pressure holding mechanism is provided.

Claims

It is a method for manufacturing a foam molded product.
The hunger zone is provided with a screw provided inside so that it can rotate and move forward and backward, and has a plasticization zone in which the thermoplastic resin is plasticized and melted to become a molten resin, and a starvation zone in which the molten resin is starved. Using a manufacturing device including a plasticizer with an introduction port for introducing a physical foaming agent into the
The manufacturing method is
In the plasticization zone, the thermoplastic resin is plasticized and melted to obtain the molten resin.
Introducing a pressurized fluid containing the physical foaming agent having a first pressure, which is a constant pressure, into the starvation zone.
In the starvation zone, starving the molten resin and
In the starvation zone, the starved molten resin and the pressurized fluid of the first pressure are brought into contact with each other.
Weighing a predetermined amount of the molten resin in contact with the pressurized fluid of the first pressure,
Including that the weighed molten resin is injected from the plasticizing cylinder and molded into the foam molded body.
The screw back pressure is maintained at a second pressure higher than the first pressure until the measurement of the molten resin is completed.
A method for producing a foamed molded product, which comprises holding the screw back pressure at a third pressure equal to or higher than the second pressure from the completion of weighing of the molten resin to the start of injection.

The foaming according to claim 1, wherein the pressure of the measured molten resin is maintained at a pressure 0.5 MPa to 10 MPa higher than the first pressure from the completion of the measurement of the molten resin to the start of injection. A method for manufacturing a molded product.

The method for producing a foamed molded product according to claim 1 or 2 , wherein the second pressure and the third pressure are the same.

The screw is provided in the plasticizing cylinder so as to be able to advance and retreat forward from the plasticizing zone toward the starvation zone and backward from the starvation zone toward the plasticizing zone.
The screw has a tip sealing mechanism for suppressing the backflow of the molten resin from the front to the rear in the plasticized cylinder.
The tip sealing mechanism is
With the screw head located at the front end of the screw,
The abutting ring located behind the screw head and
A shaft connecting the screw head and the abutting ring,
The production of the foam molded product according to claim 1 or 2, further comprising a check ring that is loosely fitted to the shaft and can be moved forward and backward between the screw head and the abutting ring. Method.

In the state where the check ring is located most forward, the ratio (S1 / S2) of the pressure receiving area S1 on the front side of the check ring to the pressure receiving area S2 on the rear side is 0.6 to 0.95. The method for producing a foamed molded product according to claim 4 , wherein the foam molded product is produced.

The check ring is formed with a through hole through which the shaft penetrates.
A part of the inner wall that partitions the through hole of the check ring forms a first tapered surface that connects the rear end portion of the through hole and the small inner diameter portion having an inner diameter smaller than the inner diameter of the rear end portion. ,
The shaft has a second tapered surface that connects the connection with the abutment ring and a small diameter portion having a diameter smaller than the diameter of the connection.
The taper ratio of the first tapered surface and the taper ratio of the second tapered surface are substantially the same.
The method for producing a foamed molded article according to claim 4 or 5 , wherein the first tapered surface and the second tapered surface are separated and abutted with each other as the check ring moves forward and backward.

The method for producing a foamed molded product according to any one of claims 4 to 6 , wherein a groove is formed on the outer surface of the check ring.

The method for producing a foamed molded product according to claim 7 , wherein the groove forms a labyrinth structure on the outer surface of the check ring.

The screw is provided in the plasticizing cylinder so as to be able to advance and retreat forward from the plasticizing zone toward the starvation zone and backward from the starvation zone toward the plasticizing zone, and positively feeds the molten resin forward. Rotation and reverse rotation opposite to forward rotation are possible,
The screw has a tip sealing mechanism for suppressing the backflow of the molten resin from the front to the rear in the plasticized cylinder.
The tip sealing mechanism is
With the screw head located at the front end of the screw,
The abutting ring located behind the screw head and
A shaft connecting the screw head and the abutting ring,
A check ring that is loosely fitted to the shaft and can move forward and backward between the screw head and the abutting ring.
It has a locking mechanism that keeps the check ring in contact with the abutt ring by rotating the screw in the reverse direction.
The method for producing a foamed molded product according to claim 1 or 2, further comprising maintaining the state in which the check ring is in contact with the abutting ring by rotating the screw in the reverse direction after the measurement of the molten resin is completed. The method for producing a foam molded product according to the above method.

A manufacturing device that manufactures foam molded products.
It is provided with a screw provided inside so that it can rotate and move forward and backward, and has a plasticization zone in which the thermoplastic resin is plasticized and melted to become a molten resin, and a starvation zone in which the molten resin is starved, and the starvation zone. A plasticizer for introducing a physical foaming agent is formed in the plasticizer, and a plasticizer that measures a certain amount of the molten resin and injects it to the outside.
A physical foaming agent supply mechanism that supplies a physical foaming agent having a first pressure, which is a constant pressure, to the plasticizer cylinder.
The screw back pressure is held at a second pressure higher than the first pressure until the measurement of the molten resin is completed, and the screw back pressure is kept at the second pressure from the completion of the measurement of the molten resin to the start of injection. A manufacturing apparatus comprising a pressure holding mechanism configured to hold a third pressure equal to or higher than the pressure.

The pressure holding mechanism is characterized in that the pressure of the measured molten resin is held at a pressure 0.5 MPa to 10 MPa higher than the first pressure from the completion of the measurement of the molten resin to the start of injection. The manufacturing apparatus according to claim 10.

The manufacturing apparatus according to claim 10 or 11 , wherein the pressure holding mechanism is a screw driving mechanism for controlling screw back pressure.

The screw is provided in the plasticizing cylinder so as to be able to advance and retreat forward from the plasticizing zone toward the starvation zone and backward from the starvation zone toward the plasticizing zone.
The screw has a tip sealing mechanism for suppressing the backflow of the molten resin from the front to the rear in the plasticized cylinder.
The manufacturing apparatus according to claim 10 or 11 , wherein the pressure holding mechanism is the tip sealing mechanism.

In the plasticized cylinder, the screw can rotate forward to send the molten resin forward and rotate in the reverse direction opposite to the forward rotation.
The tip sealing mechanism is
With the screw head located at the front end of the screw,
The abutting ring located behind the screw head and
A shaft connecting the screw head and the abutting ring,
A check ring that is loosely fitted to the shaft and can move forward and backward between the screw head and the abutting ring.
The manufacturing apparatus according to claim 13 , further comprising a locking mechanism for maintaining a state in which the check ring is in contact with the abutting ring by rotating the screw in the reverse direction.