JP2024034906A - Cleaning agent for molding machines - Google Patents

Abstract

[Problem] To provide a molding machine cleaner with higher productivity. [Solution] The cleaning agent is made of resin for cleaning the inside of a molding machine, and contains 0.2 to 5 parts by weight of polyvinylpyrrolidone per 100 parts by weight of polysulfone. It is possible to improve the productivity of the cleaning agent for molding machines, improve the cleaning effect, and improve the mold release effect. Furthermore, the cleaning agent may contain 0.03 to 1 part by weight of a compound having a phosphite structure and a hindered phenol structure. [Selected Figure] Figure 1

Description

The present invention relates to a cleaning agent for molding machines.

In the above technical field, Patent Document 1 describes a molding machine containing 30 to 90% by mass of a thermoplastic resin and 70 to 10% by mass of glass fibers with an average length of 100 μm or less, and having a flash temperature of 400°C or higher. A cleaning agent is disclosed.

Japanese Patent Application Publication No. 2011-252061

However, the technique described in the above-mentioned document actually uses polycarbonate as the main raw material and has poor mold releasability.

An object of the present invention is to provide a technique for solving the above-mentioned problems.

In order to achieve the above object, the molding machine cleaning agent according to the present invention contains 0.2 to 5 parts by weight of polyvinylpyrrolidone per 100 parts by weight of polysulfone.

According to the present invention, a higher quality molding machine cleaning agent can be provided.

FIG. 1 is a block diagram showing the configuration of a hollow fiber processing system according to a first embodiment. 3 is a flowchart illustrating the process flow of the hollow fiber processing system according to the first embodiment. It is a table showing experimental results of the device according to the first embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail below by way of example with reference to the drawings. However, the components described in the following embodiments are merely examples, and the technical scope of the present invention is not intended to be limited thereto.

[First embodiment]
A molding machine cleaning agent manufacturing system 100 as a first embodiment of the present invention will be described using FIG. 1. As shown in FIG. 1, the molding machine cleaning agent manufacturing system 100 includes a shredding device 101, a kneading device 102, and a granulator 103.

The shredding device 101 cuts into small pieces (for example, 10 mm to 30 mm) hollow fibers 110 made of polysulfone (PSF) and their scraps, which are discarded as scraps in the dialyzer manufacturing process. The polysulfone hollow fiber 110 and its ends contain 1 to 5 wt% of polyvinylpyrrolidone (PVP), which is added during production.

The kneading device 102 generates a polysulfone resin molding material by kneading a specific compound into the shredded polysulfone pieces 130, and stabilizes the polyvinylpyrrolidone added to the polysulfone.

The polysulfone to which polyvinylpyrrolidone is added and the stabilizer are both solid, and are generally mixed using a mixer such as a tumbler, blender, or mixer without melting the resin.

At this stage, the polysulfone to which polyvinylpyrrolidone has been added and the stabilizer are in a non-uniformly mixed state.

This polyvinylpyrrolidone does not have sufficient heat resistance against the high temperature conditions of approximately 300°C (melting temperature of polysulfone) in the subsequent granulation process (extrusion molding process). That is, it decomposes during extrusion molding, causing discoloration of the resin. Therefore, as a result of investigating various stabilizers to reduce this discoloration, it was found that a compound having a phosphite structure and a hindered phenol structure in the same molecule is particularly effective. Therefore, a compound having a phosphite structure and a hindered phenol structure in the same molecule is selected as the stabilizer added by the kneading and extrusion device 102.

The granulator 103 melts the polysulfone resin molding material to which a stabilizer has been added and pelletizes it by extrusion molding. In this step, the stabilizer is uniformly dispersed in the polysulfone resin to prevent deterioration of the polyvinylpyrrolidone.

As a result, polysulfone hollow fibers discarded during the dialyzer manufacturing process can be reused as a heat-resistant molding material. According to this embodiment, it is possible to suppress discoloration during pellet production, and it is possible to provide a high-quality cleaning agent for a molding machine.

[Cleaning agent for molding machines]
0.2 to 5 parts by weight of polyvinylpyrrolidone is contained per 100 parts by weight of the hollow fiber pulverized product. More preferably, 0.03 to 1 part by weight of a stabilizer is further added.

(stabilizer)
The stabilizer used in this embodiment is a compound having a phosphite structure and a hindered phenol structure in the same molecule, for example, 6-tert-butyl-4-[3-[(2,4,8 ,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphepin-6-yl)oxy]propyl]-2-methylphenol.

This example is represented by the structural formula below.

式中、Ｒ₁、Ｒ₂、Ｒ₄およびＲ₅は、それぞれ独立に水素原子、炭素数１～８のアルキル基、炭素数５～８のシクロアルキル基、炭素数６～１２のアルキルシクロアルキル基、炭素数７～１２のアラルキル基または炭素数７～１２のフェニル基を表し、Ｒ₃は水素原子または炭素数1～8のアルキル基を表す。Ｘは単結合、イオウ原子または-ＣＨＲ₆-基を表す。Ｒ₆は水素原子、炭素数１～８のアルキル基または炭素数５～８のシクロアルキル基を表す。Ａは炭素数２～８のアルキレン基または*-ＣＯＲ₇-基を表す。Ｒ₇は単結合または炭素数1～8のアルキレン基を表し、*印を付したＣＯは上記構造式におけるフォスファイト構造の酸素原子と結合していることを表す。ＹおよびＺは、いずれか一方がヒドロキシル基、炭素数１～８のアルコキシ基または炭素数７～１２のアラルキルオキシ基を表し、他方が水素原子または炭素数１～８のアルキル基を表す。

In the formula, R ₁ , R ₂ , R ₄ and R ₅ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or an alkylcycloalkyl group having 6 to 12 carbon atoms. R ₃ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. X represents a single bond, a sulfur atom or a -CHR ₆ - group. R ₆ represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms. A represents an alkylene group having 2 to 8 carbon atoms or a *-COR ₇ - group. R ₇ represents a single bond or an alkylene group having 1 to 8 carbon atoms, and CO marked with * represents a bond to the oxygen atom of the phosphite structure in the above structural formula. One of Y and Z represents a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms, and the other represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.

When Y in the structural formula is a hydroxyl group, one of R ₄ and R ₅ is an alkyl group having 3 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl group having 6 to 12 carbon atoms, Represents an aralkyl group or phenyl group having 7 to 12 carbon atoms.

Two R ₁ , two R ₂ , and two R ₃ in the structural formula may be the same or different.

(Principle of stabilizing polyvinylpyrrolidone with the above stabilizer)
Polyvinylpyrrolidone is classified as an olefin polymer. Polyvinylpyrrolidone easily undergoes a decomposition reaction under extremely high temperature conditions such as the processing temperature of polysulfone, and in an oxygen-containing atmosphere. The metastable structural substance (hydroperoxide) generated by the primary antioxidant either (1) reacts with the secondary antioxidant to become a stable structure, or (2) the hydroperoxide becomes active again due to heat. This is a competitive reaction between generating radicals and alkoxy radicals and starting a chain reaction of decomposition.

Since the polysulfone processing temperature of 300°C or higher is higher than the normal olefin processing temperature of 150-230°C, it is presumed that the hydroperoxide decomposition reaction is extremely rapid. Therefore, it is considered that the presence of the secondary antioxidant near the hydroperoxide has a time advantage over this competitive reaction and quickly stabilizes the generated hydroperoxide. Therefore, it is better to use a stabilizer that has both a primary antioxidant structure and a secondary antioxidant structure (for example, Sumilizer GP) in its molecule. It is thought that stabilization can be achieved more efficiently than using in combination.

(Production method of polysulfone resin molding material)
The method for manufacturing polysulfone pellets from dialyzer scraps is not particularly limited, and for example, the method shown in the flowchart of FIG. 2 can be applied.

In step S201, polysulfone, a stabilizer which is a heat resistant agent, and other optional components are mixed all at once or divided into a plurality of parts as necessary. That is, it is charged into a cylinder of a melt kneading machine such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, and a mixing roll.

Next, in step S203, the components charged in the cylinder are heated using the heater of the melt-kneader to melt the polysulfone.

In step S205, the melted polysulfone and the stabilizer are kneaded by the rotation of the screw of the melt kneader to form a kneaded product in which the charged components are sufficiently mixed. At this time, the stabilizer suppresses the decomposition of polyvinylpyrrolidone and suppresses odor and discoloration.

In step S207, the kneaded material is extruded from a die to form a string-like strand.

Next, in step S209, the strand is immersed in a water bath and immediately cooled.

Finally, in step S211, the cooled strand-like kneaded material is pelletized using a pelletizer to obtain a pelletized cleaning agent for a molding machine.

As described above, according to this embodiment, a higher quality cleaning agent for a molding machine can be obtained.

(Experimental equipment and conditions)
The experiment was conducted under the following conditions.

(material)
Polysulfone PSU: Solvey UDEL P-3500
Polyvinylpyrrolidone PVP: Luviskol K-90 manufactured by BASF
Hollow fiber recycled product A: PVP content 2.0wt%
Hollow fiber recycled product B: PVP content 2.4wt%
Stabilizer: Sumilizer GP manufactured by Sumitomo Chemical
(sample preparation)
Extruder: Single screw extruder PSV-30mm single screw extruder manufactured by Plaengi Co., Ltd. Processing temperature: 320-330℃, Screw rotation speed: 80rpm
(Releasability evaluation)
Extruder: Single screw extruder PSV-30mm single screw extruder manufactured by Plaengi Co., Ltd. Processing temperature: 320-330℃, Screw rotation speed: 80rpm
Evaluate the peelability when opening the tip die and removing the resin remaining inside using a metal spatula (cleanability evaluation)
Molding machine evaluation: ROBOSHOT S-2000i 50A manufactured by FANUC Corporation
Cylinder setting temperature: 360℃
1) Polyetherimide (PEI): Use 500g of Ultem 1000 (red) manufactured by Sabic and put it into the cylinder of the molding machine, repeat the plasticization injection, make the inside of the cylinder Ultem 1000 (red), and then discharge as much as possible. (Some resin remains in the screw groove etc.)
2) Add 1kg of cleaning resin to purge the residual resin of Ultem (red). Weigh the amount of red colored resin. It is judged that the cleaning performance is better if the red resin is completely discharged with a small amount of cleaning resin.
3) After draining the cleaning agent, add 500g of Ultem 1000 (natural color, N) and make sure the remaining cleaning agent is completely drained. Weigh the amount of resin mixed with cleaning agent. It is judged that the ability to be replaced is better if it is completely discharged in a small amount.

(Example 1)
PVP1.0wt% was added to PSU99.0wt%. There was no decomposition of the cleaning agent, the amount of cleaning agent required was 0.43kg, the amount of residual cleaning agent was 0.14kg, and there were only a few problems with peeling, making it possible to create a cleaning agent that was sufficiently usable.

(Example 2)
PVP 2.4wt% was added to PSU97.6wt%. There was no decomposition of the cleaning agent, the amount of cleaning agent required was 0.41kg, the amount of residual cleaning agent was 0.13kg, there were no problems with peeling, and a high-quality cleaning agent was achieved.

(Example 3)
PVP 5wt% was added to PSU 95wt%. There was no decomposition of the cleaning agent, the amount of cleaning agent required was 0.42kg, the amount of residual cleaning agent was 0.12kg, there were no problems with peeling, and a high-quality cleaning agent was achieved.

(Example 4)
66.7wt% of PSU was mixed with 33.3% of recycled hollow fiber A. As a result, the composition ratio was 99.3% PSU and 0.7wt% PVP. There was no decomposition of the cleaning agent, the amount of cleaning agent required was 0.48kg, the amount of residual cleaning agent was 0.13kg, and there were only a few problems with peeling, making it possible to create a cleaning agent with excellent productivity and sufficient for use.

(Example 5)
33.3wt% of PSU was mixed with 66.7% of recycled hollow fiber A. As a result, the composition ratio was 98.6% PSU and 1.4wt% PVP. There was no decomposition of the cleaning agent, the amount of cleaning agent required was 0.43kg, the amount of residual cleaning agent was 0.11kg, there were no problems with peeling, and a high-quality cleaning agent with excellent productivity was realized.

(Example 6)
100% recycled hollow fiber A was used. As a result, the composition ratio was 98% PSU and 2wt% PVP. There was no decomposition of the cleaning agent, the amount of cleaning agent required was 0.42kg, the amount of residual cleaning agent was 0.12kg, there were no problems with peeling, and a high-quality cleaning agent with excellent productivity was realized.

(Example 7)
100% recycled hollow fiber B was used. As a result, the composition ratio was 97.6% PSU and 2.4wt% PVP. There was no decomposition of the cleaning agent, the amount of cleaning agent required was 0.39kg, the amount of residual cleaning agent was 0.12kg, there were no problems with peeling, and a high-quality cleaning agent with excellent productivity was realized.

(Example 8)
A stabilizer was further added to hollow fiber recycled product A. As a result, the composition ratio was 97.5 wt% PSU, 2 wt% PVP, and 0.5 wt% stabilizer. There was no decomposition of the cleaning agent, the amount of cleaning agent required was 0.41kg, the amount of residual cleaning agent was 0.11kg, there were no peeling problems, no discoloration, no odor, and we were able to create a very high-quality cleaning agent with excellent productivity. .

(Comparative example 1)
PSU 100wt% was used as a cleaning agent. There was no decomposition of the cleaning agent, the amount of cleaning agent required was 0.45kg, the amount of residual cleaning agent was 0.14kg, and there were problems with peeling and sticking.

(Comparative example 2)
A conventional product containing 60 wt% polycarbonate and 40 wt% glass fiber was used. There was decomposition of the cleaning agent and sticking occurred.

(Comparative example 2)
A conventional product containing 16 wt% polypropylene and 45 wt% glass fiber to 39 wt% polycarbonate was used. There was decomposition of the cleaning agent and sticking occurred.

(Experimental result)
FIG. 3 summarizes the results of the above examples and comparative examples in one drawing. From the above Examples and Comparative Examples, it was confirmed that a high quality molding machine cleaning agent could be obtained by containing 0.2 to 5 parts by weight of polyvinylpyrrolidone to 100 parts by weight of polysulfone.

[Other embodiments]
Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above embodiments. The structure and details of the present invention can be modified in various ways within the technical scope of the present invention, which can be understood by those skilled in the art.

In order to achieve the above object, the molding machine cleaning agent according to the present invention is a molding machine cleaning agent containing 100 parts by weight of polysulfone as a main component and 0.2 to 5 parts by weight of polyvinylpyrrolidone.

Claims (8)

A molding machine cleaning agent containing 0.2 to 5 parts by weight of polyvinylpyrrolidone per 100 parts by weight of polysulfone. The cleaning agent for a molding machine according to claim 1, further comprising 0.03 to 1 part by weight of a compound having a phosphite structure and a hindered phenol structure. The cleaning agent for a molding machine according to claim 2, wherein the compound has the following structural formula.

[In the formula, R ₁ , R ₂ , R ₄ and R ₅ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or an alkylcyclo having 6 to 12 carbon atoms. It represents an alkyl group, an aralkyl group having 7 to 12 carbon atoms, or a phenyl group having 7 to 12 carbon atoms, and R ₃ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. X represents a single bond, a sulfur atom or a -CHR ₆ - group. R ₆ represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms. A represents an alkylene group having 2 to 8 carbon atoms or a *-COR ₇ - group. R ₇ represents a single bond or an alkylene group having 1 to 8 carbon atoms, and CO marked with * represents a bond to the oxygen atom of the phosphite structure in the above structural formula. One of Y and Z represents a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms, and the other represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. ] When Y in the structural formula according to claim 3 is a hydroxyl group, one of R ₄ and R ₅ is an alkyl group having 3 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or a cycloalkyl group having 6 to 12 carbon atoms. The cleaning agent for a molding machine according to claim 3, which represents an alkylcycloalkyl group, an aralkyl group having 7 to 12 carbon atoms, or a phenyl group. The cleaning agent for a molding machine according to claim 3, wherein two R ₁ , two R ₂ , and two R ₃ in the structural formula according to claim 3 are different from each other. 6-tert-butyl-4-[3-[(2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphepin-6-yl)oxy The cleaning agent for a molding machine according to claim 3, which is propyl]-2-methylphenol. The cleaning agent for a molding machine according to claim 1, which is a pellet formed from a pulverized polysulfone hollow fiber containing 0.2 to 5 parts by weight of polyvinylpyrrolidone. It is a pellet made by adding 0.03 to 1 part by weight of a compound having a phosphite structure and a hindered phenol structure in the same molecule to a pulverized product of polysulfone hollow fibers containing 0.2 to 5 parts by weight of polyvinylpyrrolidone. The cleaning agent for a molding machine according to claim 1.

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