JP2002060792A - Cleaning agent for resin holding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning agent for a resin molding machine capable of effectively removing resin remaining in the molding machine in a short time and easily removing the cleaning agent itself by the next resin material. SOLUTION: This cleaning agent for resin molding machine comprises (C) 0.05-5 pts.mass. of a lubricant comprising a saturated aliphatic alcohol per 100 pts.mass. of a polymer mixture comprising (A) 70-99 pts.mass. of a non-cross- linked polymer obtained from 85-100 mass.% of methyl methacrylate and 0-15 mass.% of an acrylate, (B) 1-30 pts.mass of a cross-linked polymer having average particle size of 50-300 μm obtained by a cross-linking polymerization of 85-100 mass.% of methyl methacrylate and 0-15 mass.% of an acrylate, and the cleaning agent has a melt index of 0.05-2.0 g/10 min (230 deg.C, 98N), heat mass decreasing rate of 3-40% (under nitrogen atmosphere, 280 deg.C, 20 min).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating cylinder, a screw and the like of a resin molding machine used for efficiently performing material change and color changing work of a resin molding machine such as an injection molding machine and an extrusion molding machine. Cleaning agent.

[0002]

2. Description of the Related Art A resin molding machine such as an injection molding machine or an extrusion molding machine is excellent in that a single product can be mass-produced, and has greatly contributed to the development of the resin material field. However, recently, the demands of users have diversified, and it has become indispensable to produce various types of resin molded products in small quantities. As a result, the frequency of material change and color change of the resin molding machine has been increasing. For example, the most problematic in the material changing operation is the cleaning of the resin material fused to the heating cylinder and the screw of the resin molding machine.

[0003] That is, the method of disassembling the heating cylinder and the screw to mechanically clean the heating cylinder and the screw consumes too much time and labor, and thus is not adopted in ordinary work. Generally, an operation of washing and removing the residual resin in the heating cylinder with a resin to be subsequently molded is performed.
However, in such a washing operation, the exchange of the resin is incomplete, and the amount of the resin used for the washing is increased, which is uneconomical.

Therefore, a cleaning agent for efficiently changing the resin of a resin molding machine has been studied. For example, Japanese Patent Application Laid-Open No. 3-230922 discloses that
The melt index measured at 10 kg is 0.05 to 2
A detergent comprising a methacrylic polymer of 0 g / 10 minutes is disclosed. Further, for example, Japanese Patent Application Laid-Open No. 8-155969 discloses a detergent for a molding machine in which 2 to 50 parts by mass of a thermoplastic ultrapolymer is mixed with 100 parts by mass of a thermoplastic resin.

[0005] In addition, various types of cleaning agents for resin molding machines are actually commercially available, and they are roughly classified into a high viscosity type and a low viscosity type.

[0006]

However, the cleaning agents described in the above publications still have insufficient cleaning power.
In addition, among the commercially available products, a high-viscosity type cleaning agent is effective for removing the resin remaining in the heating cylinder,
It is difficult to remove the detergent with the resin to be subsequently molded, and the detergent is mixed into the molded article, and there is a defect that defects such as bumps and silver are generated. On the other hand, it is difficult for the low-viscosity type cleaning agent to completely remove the residual resin in the heating cylinder, and the low-viscosity type cleaning agent is mixed into a molded product which is subsequently molded. Furthermore, surfactants, foaming agents, plasticizers, etc. are used in large amounts in this type of detergent,
Even a small amount of the detergent may be mixed into the molded article, resulting in a decrease in mechanical properties and thermal properties.

[0007] In addition, there is a commercially available product of an inorganic filler added type, which is similar to the high viscosity type.
Although it is effective for removing the resin remaining in the heating cylinder, it is difficult to remove the inorganic filler with the resin that is subsequently molded, and it has the disadvantage that silver-like appearance defects occur when mixed into molded products. is there.

[0008] An object of the present invention is to solve the above-mentioned problems of the prior art, and more specifically, to efficiently remove resin remaining in a heating cylinder of a resin molding machine in a short time. An object of the present invention is to provide a detergent for a resin molding machine, which can be easily removed by a resin material to be molded next.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted various studies to achieve the above object, and as a result, have found that a specific polymer containing methyl methacrylate as a main component or the like is mixed at a specific composition ratio. The agent was found to be very effective and completed the present invention.

That is, the present invention relates to methyl methacrylate 8
Non-crosslinked polymer (A) 7 obtained by polymerizing a monomer containing 5 to 100% by mass and 0 to 15% by mass of an acrylate ester
Crosslinked polymer (B) 1 having an average particle size of 50 to 300 μm obtained by crosslinking and polymerizing 0 to 99 parts by mass of a monomer containing 85 to 100% by mass of methyl methacrylate and 0 to 15% by mass of an acrylate ester. A lubricant (C) of 0.05 to 5 parts by mass was added to 100 parts by mass of a polymer mixture consisting of
The melt index measured at 98C and 0 ° C is 0.05.
Ｇ2.0 g / 10 min, and 280 in a nitrogen atmosphere.
A cleaning agent for a resin molding machine having a mass reduction rate of 3 to 40% when heated at 20C for 20 minutes.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.

In the present invention, the non-crosslinked polymer (A) comprises
A polymer containing methyl methacrylate as a main component, specifically, a polymer obtained by polymerizing a monomer containing 85 to 100% by mass of methyl methacrylate and 0 to 15% by mass of an acrylate ester.

The acrylate ester used as necessary for the non-crosslinked polymer (A) is a useful component for adjusting the melt viscosity of the detergent. The type of the acrylate is not particularly limited, and may be any as long as it can be copolymerized with methyl methacrylate at 15% by mass or less. As a specific example,
Examples thereof include methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate.

The amount of the acrylate ester used is 0 to 15% by mass in the monomer. When the content exceeds 15% by mass, when the detergent is decomposed in a heating cylinder or the like, unmelted matter is easily generated, which causes generation of carbide. In the present invention, a cleaning agent having a low mass reduction rate by thermal decomposition is obtained by suppressing the acrylate in the polymer (A) to 15% by mass or less.

The non-crosslinked polymer (A) can be obtained by various known polymerization methods such as a suspension polymerization method, a bulk polymerization method, an emulsion polymerization method and a solution polymerization method.

In the present invention, the crosslinked polymer (B) is also a polymer containing methyl methacrylate as a main component, specifically, 85 to 100% by mass of methyl methacrylate and 0 to 15% by mass of an acrylate ester. Is obtained by crosslinking polymerization of a monomer containing

The average particle size of the crosslinked polymer (B) is 50 to 3
It is within the range of 00 μm, particularly preferably within the range of 100 to 200 μm. The average particle size was measured using a micro-type electromagnetic vibration sieve M-2 (manufactured by Tsutsui Physical and Chemical Instruments).
Sample mass 10 g, vibrating time of sieve 15 minutes, mesh 30 μm to 350 μm
It is a value calculated by the sum of (various particle size × sample mass) / the total of sample mass (10 g).

The crosslinked polymer (B) is generally obtained by further adding a crosslinking agent to a monomer containing 85 to 100% by mass of methyl methacrylate and 0 to 15% by mass of an acrylate ester. It is obtained as a particulate polymer by crosslinking polymerization by turbid polymerization. Alternatively, a lump-shaped crosslinked copolymer may be produced once and then pulverized to obtain a particulate polymer.

As the acrylate used as necessary for the crosslinked polymer (B), the same acrylates as used for the non-crosslinked polymer (A) can be used.

As the cross-linking agent used for the cross-linked polymer (B), it is preferable to use a monomer having a polymerizable polyfunctional group such as a divinyl compound and a diallyl compound. When a polyfunctional monomer is used as a cross-linking agent, this polyfunctional monomer is different from a monomer containing methyl methacrylate and, if necessary, an acrylate ester, and separately defines its mass. . The amount of the crosslinking agent used, such as a polyfunctional monomer, is 0.5 to 100 parts by mass of a monomer containing methyl methacrylate and, if necessary, an acrylate ester.
15 parts by weight are preferred.

Non-crosslinked polymer (A) and crosslinked polymer (B)
The composition ratio is based on a total of 100 parts by mass of both.
The non-crosslinked polymer (A) is 70 to 99 parts by mass, and the crosslinked polymer (B) is 1 to 30 parts by mass. In particular, the non-crosslinked polymer (A) is 80 to 95 parts by mass, and the crosslinked polymer (B) is 5-2.
It is preferably 0 parts by mass.

In the present invention, the lubricant (C) is composed of a saturated aliphatic alcohol, and the addition of the lubricant improves the cleaning effect. The saturated aliphatic alcohol preferably has a carbon number in the range of 16 to 19. In particular, stearyl alcohol and cetyl alcohol are most suitable because they hardly stay in the heating cylinder.

The lubricant (C) is used in an amount of 0.05 to 5 parts by mass, preferably 0.2 to 3 parts by mass, per 100 parts by mass of the polymer mixture comprising the non-crosslinked polymer (A) and the crosslinked polymer (B). Add parts by weight.

The cleaning agent of the present invention can be obtained by mixing the non-crosslinked polymer (A), the crosslinked polymer (B) and the lubricant (C) described above and pelletizing the mixture with, for example, an extruder. Further, the cleaning agent of the present invention is a composition containing these components (A) to (C) as main components, and various conventionally known additives can be further added as desired. For example, a stabilizer can be added for controlling the heat decomposition property, and a plasticizer can be added for plasticizing stability. These additives may be added when, for example, the components (A) to (C) are blended and blended, and may be pelletized by an extruder.

The detergent of the present invention has a melt index measured at 230 ° C. and 98 N in the range of 0.05 to 2.0 g / 10 minutes. This melt index is ASTM
It is a value measured according to D-1238. If the melt index exceeds 2.0 g / 10 minutes, the melt viscosity in the heating cylinder decreases, and the effect of removing the residual resin decreases. If it is less than 0.05 g / 10 minutes,
The screw motor load when plasticizing the cleaning agent in the heating cylinder increases, and not only plasticization cannot be performed smoothly, but also the cleaning agent remains in the heating cylinder and becomes difficult to remove with the resin to be subsequently molded. .

The cleaning agent of the present invention has a viscosity of 280 in a nitrogen atmosphere.
The mass loss rate when heated at 20C for 20 minutes is 3 to 40%. If the mass reduction rate is less than 3%, it takes a long time to lower the melt viscosity, so that an efficient operation cannot be performed, and a detergent may be mixed into the molded article. On the other hand, if it exceeds 40%, the melt viscosity is significantly reduced at the time when the detergent is plasticized in the heating cylinder, and the removal of the residual resin becomes insufficient.

The cleaning agent for the resin molding machine is required to be able to remove the resin remaining in the heating cylinder and the like, and to be able to remove the cleaning agent by the resin material to be molded next. The cleaning agent of the present invention removes residual resin in a heating cylinder or the like when in a state of high melt viscosity, and at the stage of removing the cleaning agent with a molding material to be molded next, its thermal decomposition property works effectively. The melt viscosity of the detergent decreases, and the detergent can be easily removed with the resin material.

[0028]

The present invention will be described in more detail with reference to the following examples.

[Example 1] 1. Production of non-crosslinked polymer (A) containing methyl methacrylate as a main component: To 9.9 kg of methyl methacrylate and 0.1 kg of methyl acrylate, 6 g of azobisisobutyronitrile and 8 g of n-octyl mercaptan are added. Stir to obtain a homogeneous solution. Next, this homogeneous solution was charged into a 50 L jacketed polymerization tank containing a solution obtained by adding 3 g of sodium polymethacrylate to 30 kg of water and stirred. Then, warm water is passed through the jacket and heated to 80
The polymerization reaction was performed at a temperature of 3 ° C for 3 hours. Wash the obtained polymer with water,
After drying, beads of a non-crosslinked polymer (A) containing methyl methacrylate as a main component were obtained.

2. Production of crosslinked polymer (B) containing methyl methacrylate as a main component: 6 g of azobisisobutyronitrile is added to 10 kg of methyl methacrylate and 1 kg of ethylene glycol dimethacrylate as a cross-linking agent, and the mixture is stirred. In the same manner as in the process for producing the non-crosslinked polymer (A), except for using the above, beads of a crosslinked polymer (B) having an average particle diameter of 100 μm were obtained.

3. Production of detergent: 80 parts by mass of beads of the non-crosslinked polymer (A) produced as described above and 20 parts by mass of beads of the crosslinked polymer (B) are blended, and stearyl alcohol as a lubricant (C) is further blended. Was added and blended, and pelletized with a 40φ vent extruder.
The cleaning agent of the present invention was obtained. The melt index (230 ° C., 98N) of this detergent was 0.6 g / 10 minutes, and the mass reduction rate (280 ° C., 20 minutes) was 12%.

4. Evaluation of detergent: First, as a first injection molding step, an injection molding machine (made by Toshiba, IS80FPA3).
, Injection molding of PC-PBT resin (polycarbonate-polybutylene terephthalate resin, manufactured by GE, USA, trade name: Zenoi 1731 black) was performed for a desired time.

Next, as a washing step, the cylinder temperature 2
The temperature was set to 60 ° C., the number of revolutions of the screw was set to 70 rpm, and 1 kg of the cleaning agent was added to perform cleaning. As a result, the residual PC-PBT resin could be sufficiently removed in a short time.
Thereafter, 2 kg of a methacrylic resin (manufactured by Mitsubishi Rayon Co., Ltd., trade name: Acrypet VH Clear) was charged and washing was performed. As a result, the cleaning agent remaining in the heating cylinder was sufficiently removed in a short time.

After the cleaning agent was sufficiently removed, a methacrylic resin flat plate having a thickness of 100 mm × 100 mm × 3 mm was formed as a second injection molding step. There was no particular problem in the transparency and appearance of the flat plate, and high transparency and appearance unique to methacrylic resin were obtained.

[Examples 2 and 3] Components (A) to (C)
The cleaning agent of the present invention was manufactured and evaluated in the same manner as in Example 1 except that the composition ratio of was changed as shown in Table 1.
The amount of the detergent used was 1.5 kg in Example 2, and Example 3
In this case, as in Example 1, the residual PC-PBT resin could be sufficiently removed by washing in a short time. The amount of the methacrylic resin used to remove the detergent is 2 kg in Example 2, 3 kg in Example 3,
As in Example 1, with such a small amount of the methacrylic resin, the residual detergent could be sufficiently removed in a short time.
Table 1 shows the results.

[0036]

[Table 1]

Comparative Example 1 A methacrylic resin flat plate was prepared in the same manner as in Example 1, except that the residual PC-PBT resin was removed with 5 kg of methacrylic resin without using a detergent in the cleaning step. However, residual PC-P
The BT resin could not be sufficiently removed, and the methacrylic resin flat plate obtained in the second injection molding step was cloudy due to the incorporation of the PC-PBT resin.

Therefore, the amount of methacrylic resin used in the washing step was increased to 8 kg to 10 kg, and the first injection molding step, the washing step, and the second injection molding step were performed again. A methacrylic resin flat plate having the same was obtained.

[Comparative Example 2] In a washing step, a ground product of ultra-high molecular weight methacrylic resin (Acrylite L, trade name, manufactured by Mitsubishi Rayon Co., Ltd.) was used in place of the detergent of the present invention for 1 k.
The remaining PC-PBT resin was removed using g, and thereafter, 3 kg of methacrylic resin was charged, and a methacrylic resin flat plate was produced in the same manner as in Example 1 except that the ultrahigh molecular weight methacrylic resin was removed. However, PC-PBT
Although the resin was sufficiently removed, the removal of the residual ultrahigh molecular weight methacrylic resin was insufficient, and the residual ultrahigh molecular weight methacrylic resin was confirmed on the methacrylic resin plate obtained in the second injection molding step. Bad appearance had occurred.

[0040]

As described above, by using the cleaning agent of the present invention, the resin remaining in the heating cylinder of the resin molding machine can be efficiently removed in a short time. The cleaning agent can be easily removed with the resin material to be molded. Therefore, if the cleaning agent of the present invention is used, a material change, a color change operation, and the like of the resin molding machine can be efficiently performed.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yukinori Okimoto 20-1 Miyukicho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Otake Works F-term (reference) 4F206 AM12 JA07 JL03 JL04 JP30 4F207 AM12 KA01 KM20 4H003 DA12 DB01 EB04 EB28 EB30 FA21

Claims (1)

[Claims] 1. 85 to 100% by weight of methyl methacrylate
And a non-crosslinked polymer (A) obtained by polymerizing a monomer containing 0 to 15% by mass of acrylate and 85 to 100% by mass of methyl methacrylate and 0 to 15% by mass of acrylate % Of a polymer mixture consisting of 1 to 30 parts by mass of a crosslinked polymer (B) having an average particle size of 50 to 300 μm obtained by crosslinking and polymerizing a monomer containing 0.1% by mass of a saturated aliphatic alcohol. 0.05 to 5 parts by mass of a lubricant (C) was added.
Melt index measured at 98N is 0.05 to 2.0
g / 10 minutes and 280 ° C., 20 in a nitrogen atmosphere.
A detergent for a resin molding machine having a mass reduction rate of 3 to 40% when heated for a minute.