JP2021003873A - Manufacturing method for thermoplastic molded products - Google Patents

Abstract

To provide a method for manufacturing thermoplastic molded products with less foreign matter contamination.SOLUTION: A method for manufacturing a thermoplastic resin molded body by a melt extrusion method in which a gear pump is arranged between the extruder and the die, and the amount of leaked resin from the gear pump is 0.10 to 2.00 mass parts per 100 mass parts of the thermoplastic resin composition discharged from the die.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a thermoplastic resin molded product.

Thermoplastic resin molded products are widely used for decoration of automobiles and home appliances, optical applications, building materials, etc. However, if minute foreign substances are mixed in the thermoplastic resin molded product, the appearance and quality of the final product will be impaired. Therefore, a method for removing foreign substances is being studied.
For example, a method of removing foreign matter by arranging a filter device having a filtration accuracy of 25 μm or less during the process from the extruder to the die has been proposed (Patent Document 1). Further, a method of filtering using a leaf disk type filter device having a filtration accuracy of 3 to 25 μm (Patent Document 2) has also been proposed. Further, a method has been proposed in which foreign matter is suppressed from being mixed by discharging the resin that has accumulated and gelled in the manufacturing process from a discharge port provided in a leaf disc type filter device (Patent Document 3).

JP-A-2009-39935 Japanese Unexamined Patent Publication No. 2010-17948 JP-A-2009-154301

According to the methods proposed in Patent Documents 1 to 3, it is possible to suppress the mixing of foreign substances to some extent, but it is not sufficient.
The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a method for producing a thermoplastic resin molded product in which foreign matter is less likely to be mixed.

As a result of studying the above problems, the present inventor has found that by discharging a certain amount of retained resin from the gear shaft portion of the gear pump to the outside, it is possible to suppress the mixing of foreign matter into the thermoplastic resin molded product. The present invention has been completed.

That is, the present invention provides the following [1] to [10].
[1] A method for producing a thermoplastic resin molded product by a melt extrusion method in which a gear pump is arranged between an extruder and a die, wherein the amount of the thermoplastic resin composition discharged from the die is 100 parts by mass. A method for producing a thermoplastic resin molded product, wherein the amount of leaked resin from the gear pump is 0.10 to 2.00 parts by mass.
[2] The method for producing a thermoplastic resin molded product according to [1], wherein a polymer filter is arranged between the gear pump and the die.
[3] The method for producing a thermoplastic resin molded product according to [1] or [2], wherein the temperature of the thermoplastic resin composition in the gear pump is 230 to 300 ° C.
[4] Any one of [1] to [3], wherein the thermoplastic resin molded product is produced under the condition that the melt viscosity of the thermoplastic resin composition at a shear rate of 122 / sec is 100 to 1,500 Pa · s. The method for producing a thermoplastic resin molded article according to.
[5] The method for producing a thermoplastic resin molded product according to any one of [1] to [4], wherein the thermoplastic resin composition contains a (meth) acrylic resin as the thermoplastic resin (I).
[6] The (meth) acrylic resin is a homopolymer (A) of methyl methacrylate;
Acrylic ester homopolymer (B);
Copolymer of methyl methacrylate and acrylic ester (C);
A mixture of a homopolymer of methyl methacrylate (A) and a homopolymer of an acrylic ester (B);
A mixture of a homopolymer of methyl methacrylate (A) and a copolymer of methyl methacrylate and an acrylic acid ester (C);
The method for producing a thermoplastic resin molded product according to [5], which is at least one selected from.
[7] The method for producing a thermoplastic resin molded product according to any one of [1] to [6], wherein the thermoplastic resin composition contains rubber particles (II).
[8] The method for producing a thermoplastic resin molded product according to [7], wherein the rubber particles (II) are acrylic elastic particles.
[9] The method for producing a thermoplastic resin molded product according to any one of [1] to [8], wherein the thermoplastic resin molded product is a film.
[10] The thermoplastic according to any one of [1] to [8], wherein the thermoplastic resin molded product is one selected from an optical molded product, a decorative molded product, and a building material molded product. A method for manufacturing a resin molded product.

According to the present invention, it is possible to provide a method for producing a thermoplastic resin molded product in which foreign matter is less likely to be mixed.

[Manufacturing method of thermoplastic resin molded product]
The method for producing a thermoplastic resin molded product of the present invention is a method for producing a thermoplastic resin molded product by a melt extrusion method in which a gear pump is arranged between an extruder and a die, and the thermoplastic resin discharged from the die. The amount of leak resin from the gear pump is 0.10 to 2.00 parts by mass with respect to 100 parts by mass of the discharge amount of the composition. By setting the amount of leak resin in the gear pump to an appropriate range, the retention of the thermoplastic resin composition in the gear pump can be effectively suppressed, and the deteriorated resin can be discharged from the production line, so that foreign matter is produced. It is possible to produce a thermoplastic resin molded product that is less likely to be mixed in the line and has less foreign matter such as burnt or gel.
Conventionally, a polymer filter has been used to remove foreign substances, but even if a polymer filter is used, it may still be difficult to suppress the amount of foreign substances. In the present invention, the amount of foreign matter in the molded product can be efficiently suppressed by removing the foreign matter in the stage before the polymer filter.

Hereinafter, specific aspects of the production method of the present invention will be described in detail.
<Extruder>
The extruder used in the present invention is not particularly limited, and examples thereof include a single-screw extruder, a twin-screw extruder, and a multi-screw extruder. The extruder is preferably provided with a venting mechanism in order to remove volatile matter generated during melt-kneading. As the screw of the extruder, a barrier flight type screw or a screw with a mixing section can be used in addition to the full flight type screw. The L / D of the screw (L represents the cylinder length of the extruder and D represents the cylinder inner diameter) is not particularly limited, but is 10 to 100 in order to obtain a sufficient plasticization and kneading state. It is preferably 20 to 50, more preferably 25 to 40, and even more preferably 25 to 40. When L / D is at least the lower limit value, sufficient plasticization and kneading state can be easily obtained, and when it is at least the upper limit value, shearing heat is less likely to be applied to the resin, and thermal deterioration of the resin can be suppressed.

The cylinder temperature of the extruder is preferably 150 to 310 ° C, more preferably 180 to 280 ° C. When the cylinder temperature is at least the above lower limit value, the resin is sufficiently melted, foreign matter due to unmelted residue is unlikely to increase, and the rotational torque of the screw does not become too large, which is preferable. On the other hand, when the cylinder temperature is not more than the upper limit value, the resin is less likely to be thermally deteriorated, which is preferable.

<Gear pump>
The gear pump used in the present invention is not particularly limited as long as it is provided with a discharge port capable of discharging the resin that has accumulated without being discharged from the gear pump, and a commercially available one can be used. In the gear pump, two gears are housed in a state of being meshed with each other, and a constant amount of the thermoplastic resin composition can be discharged by driving and rotating one of the gears. Further, three or more gears can be used for the purpose of facilitating control of fluctuations in the discharge amount.

In the present invention, the amount of leak resin from the gear pump is 0.10 to 2.00 parts by mass with respect to 100 parts by mass of the discharge amount (discharge amount from the die) of the thermoplastic resin composition discharged from the die. If the amount of the leaked resin is less than 0.10 parts by mass, the resin is not properly discharged to the outside of the production line, so that the amount of foreign matter in the thermoplastic resin molded body increases. On the other hand, when the amount of the leaked resin is more than 2.00 parts by mass, the amount of the thermoplastic resin composition discharged to the outside of the production line increases and the yield decreases. The amount of leak resin from the gear pump is preferably 0.20 to 0.80 parts by mass, more preferably 0.30 to 0.50 parts by mass, and further, with respect to 100 parts by mass of the discharge amount from the die. It is preferably 0.37 to 0.45 parts by mass, and even more preferably 0.40 to 0.45 parts by mass.

The amount of leak resin from the gear pump is preferably 0.15 to 3.0 kg / hour. The lower limit of the amount of the leak resin is more preferably 0.30 kg / hour, further preferably 0.50 kg / hour, particularly preferably 0.60 kg / hour, and 0.70 kg / hour. There may be. The upper limit is more preferably 2.5 kg / hour, and may be 2.0 kg / hour, 1.0 kg / hour, or 0.80 kg / hour. ..
The amount of leak resin can be adjusted by changing the clearance of the gear shaft portion of the gear pump. The resin leak from the gear pump is preferably continuous.
The amount of leak resin from the gear pump can be measured by the method described in Examples.

The discharge amount from the die is preferably 50 to 600 kg / hour, more preferably 60 to 400 kg / hour, and more preferably 70 to 200 kg / hour, although it depends on the size of the gear pump and the like. More preferred. When the discharge amount from the die is at least the above lower limit value, thermal deterioration due to retention of the thermoplastic resin can be suppressed. On the other hand, when the discharge amount from the die is not more than the upper limit value, vent-up can be suppressed. The discharge amount from the die can be measured by the method described in Examples.

The front pressure of the gear pump is preferably 1 to 7 MPa, more preferably 2 to 6 MPa, and even more preferably 3 to 5 MPa. By setting the front pressure of the gear pump to the above lower limit value or more, thermal deterioration due to retention of the thermoplastic resin can be suppressed. Further, by setting the front pressure of the gear pump to be equal to or lower than the upper limit value, vent-up can be prevented.

The temperature (set temperature) of the thermoplastic resin composition in the gear pump is preferably 230 to 300 ° C., more preferably 240 to 280 ° C., and even more preferably 250 to 270 ° C. By setting the temperature of the thermoplastic resin composition in the gear pump to the above lower limit value or more, the melt viscosity can be lowered, and the resin can be discharged without clogging the discharge port. On the other hand, by setting the temperature of the thermoplastic resin composition in the gear pump to the above upper limit value or less, deterioration of the resin due to heat in the gear pump can be suppressed.

<Polymer filter>
In the present invention, it is preferable to arrange a polymer filter between the gear pump and the die. This makes it possible to remove foreign substances and the like that could not be leaked from the gear pump, and further reduce the amount of foreign substances in the thermoplastic resin molded body. From the above viewpoint, it is more preferable to arrange the polymer filter between the gear pump and the static mixer.
The type of polymer filter that can be used in the present invention is not particularly limited, and a housing having an inlet and an outlet for the molten resin to flow in and a filter element having a filter element arranged at a predetermined position in the housing are used. Can be used. The filter element may be either a leaf disc type or a tubular type. Examples of the tubular filter element include a tubular type such as a tube type and a candle type. Among these, a candle type filter element is preferably used.

The filtration accuracy of the filter element is preferably 5 to 50 μm, more preferably 8 to 30 μm or more, and even more preferably 10 to 25 μm. When the filtration accuracy is within the above range, the balance between productivity and suppression of foreign matter contamination can be improved. In particular, when the filtration accuracy is at least the above lower limit value, thermal deterioration due to shear heat generation when passing the molten thermoplastic resin composition can be suppressed. On the other hand, when the filtration accuracy is equal to or less than the upper limit value, foreign matter can be effectively removed.

<Static mixer>
In the present invention, it is preferable to use a static mixer for the purpose of efficiently stirring and mixing the thermoplastic resin composition while reducing the pressure loss.
The number of elements (number of unit mixing elements) of the static mixer is preferably 5 to 30, more preferably 6 to 28, and even more preferably 7 to 25. When the number of elements is within the above range, the temperature uniformity of the thermoplastic resin composition and the uniformity of each compounding component are improved. Further, when the number of elements is not more than the upper limit value, the surface area of the elements is reduced, so that it is possible to prevent the deteriorated resin from adhering to the surface of the elements, and it is possible to suppress the mixing of foreign substances.

<Die>
The die is not particularly limited and can be selected according to the shape of the thermoplastic resin molded product such as pellets, films, sheets, and plates.
When producing a film, it is preferable to use a T-die such as a manifold die, a fishtail die, and a coat hanger die. In order to stabilize the film thickness, it is preferable to use an automatic adjustment die provided with a mechanism for measuring the film thickness of the formed film and automatically adjusting the bolt of the lip opening.

<Roll>
In the production method of the present invention, from the viewpoint of improving the surface smoothness of the thermoplastic resin molded product, it is preferable that the extruded melt is picked up and pressed by using a metal mirror roll or a mirror belt. .. Examples of the metal mirror surface roll include a metal elastic roll and a metal rigid body roll, but from the viewpoint of improving the surface smoothness of the thermoplastic resin molded body, it is preferable to use the metal elastic roll and the metal rigid body roll in combination. ..

From the viewpoint of surface smoothness, the linear pressure between the mirror surface roll or the mirror surface belt is preferably 10 N / mm or more, more preferably 20 N / mm or more, and usually 50 N / mm or less.
The surface temperature of the mirror surface roll or the mirror surface belt is preferably 60 to 130 ° C., more preferably 70 to 100 ° C. from the viewpoint of surface smoothness, haze, appearance and the like.

<Film thickness>
According to the present invention, for example, a film having a film thickness of 20 to 200 μm can be produced as a thermoplastic resin molded product. Further, from the viewpoint of improving the handleability of the film and keeping the cost low, the film thickness is preferably 25 to 180 μm, more preferably 30 to 150 μm. When the film thickness is at least the lower limit value, the rigidity is increased and the handleability of the film is improved. Further, when the film thickness is equal to or less than the upper limit value, the balance between the strength of the film and the manufacturing cost is improved.

<Amount of foreign matter>
According to the present invention, for example, as a thermoplastic resin molded product, a film having a foreign matter amount of 1.5 pieces / m ² or less can be obtained. The amount of foreign matter in the film is preferably 1.0 pieces / m ² or less, more preferably 0.6 pieces / m ² or less, and further preferably 0.3 pieces / m ² or less. ..
The amount of foreign matter in the film can be measured by the method described in Examples.

<Thermoplastic resin composition>
The thermoplastic resin composition used in the present invention contains the thermoplastic resin (I) and additives added as needed.
[Thermoplastic resin (I)]
The thermoplastic resin used in the present invention is not particularly limited, and for example, polyolefins such as polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1, and polynorbornene; ethylene-based ionomers; methacrylic resins, MS resins, and the like. (Meta) acrylic resin; styrene resin such as polystyrene, high impact polystyrene, AS resin, ABS resin, AES resin, AAS resin, ACS resin, and MBS resin; ester resin such as polyethylene terephthalate and polybutylene terephthalate; Amid resins such as polyamide 6, polyamide 66, polyamide 12, polyamide 46, polyamide 9T, polyamide 10T and polyamide elastomer; polycarbonate; polyvinyl chloride, polyvinylidene chloride, vinylidene fluoride, polyvinyl alcohol, polyvinyl butyral, polyvinyl acetal, polyvinyl Phenol and ethylene-vinyl alcohol copolymers; polyacetals; polyurethanes; modified polyphenylene ethers and polyphenylene sulfides; acrylic thermoplastic elastomers; styrene thermoplastic elastomers such as SEPS, SEBS, and SIS; olefin thermoplastic elastomers and the like. Examples thereof include those composed of only coalescing components and resin compositions containing one or more of these polymer components.
Among these thermoplastic resins, it is preferable to use a (meth) acrylic resin from the viewpoint of excellent optical properties, heat resistance, molding processability, and the like.
In the present specification, the (meth) acrylic resin refers to a methacrylic resin or an acrylic resin.

Examples of the (meth) acrylic resin include a homopolymer (A) of methyl methacrylate, a homopolymer of acrylic acid ester (B), a copolymer of methyl methacrylate and acrylic acid ester (C), and methacrylic acid. From a mixture of a homopolymer of methyl (A) and a homopolymer of an acrylic acid ester (B), a homopolymer of methyl methacrylate (A) and a mixture of a copolymer of methyl methacrylate and an acrylic acid ester (C) The one selected is preferred.
The proportion of the methyl methacrylate unit contained in the copolymer (C) of methyl methacrylate and the acrylic acid ester is preferably 60 to 99% by mass, more preferably 70 to 98% by mass, and 80 to 80 to 90% by mass. It is more preferably 97% by mass.

The acrylic acid ester is not particularly limited, and examples thereof include acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate.

The weight average molecular weight (Mw) of the (meth) acrylic resin is preferably 50,000 to 150,000, more preferably 60,000 to 150,000, and 70,000 to 120,000. It is more preferable to have.
The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the (meth) acrylic resin is preferably 1.7 to 2.6, and preferably 1.7 to 2.3. More preferably, it is 1.7 to 2.2. By setting the molecular weight distribution to the above lower limit value or more, the molding processability of the thermoplastic resin composition becomes good, and it is also advantageous in that the retention of the resin in the filter device is suppressed. Further, by setting the molecular weight distribution to the above upper limit value or less, the impact resistance of the obtained thermoplastic resin molded product becomes good.
The weight average molecular weight (Mw) and the number average molecular weight (Mn) are values calculated by analysis by gel permeation chromatography (GPC) and converted into the molecular weight of standard polystyrene.

The (meth) acrylic resin can be produced by known methods such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method. Among them, a bulk polymerization method, a solution polymerization method, or a suspension polymerization method. From the viewpoint of obtaining a thermoplastic resin molded product having less impurities, those obtained by a massive polymerization method or a suspension polymerization method are more preferable.

In the present invention, one type of thermoplastic resin (I) may be used alone, or two or more types may be used in combination. When two or more kinds of thermoplastic resins are used in combination, the content of the (meth) acrylic resin in the total amount of the thermoplastic resins is preferably 70 to 95% by mass, more preferably 75 to 90% by mass. It is preferably 80 to 85% by mass, more preferably 80 to 85% by mass.

The content of the thermoplastic resin (I) in the thermoplastic resin composition used in the present invention is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more. , And preferably 95% by mass or less. When the content of the thermoplastic resin (I) is within the above range, a thermoplastic resin molded product having excellent optical properties, heat resistance, molding processability, and the like can be obtained.

[Rubber particles (II)]
The production method of the present invention can be particularly suitably used for producing a thermoplastic resin molded product containing rubber particles. Since the thermoplastic resin composition containing the rubber particles tends to generate foreign matter due to retention, it is possible to produce a thermoplastic resin molded product having less foreign matter by applying the present invention. The thermoplastic resin molded product containing the rubber particles can be produced by using the thermoplastic resin composition containing the rubber particles.
The rubber particles (II) include particles made of a polymer having a unit derived from an acrylic acid ester (hereinafter referred to as "acrylic elastic particle") and particles made of a polymer having a unit derived from a conjugated diene. , Particles made of a polymer having a unit derived from an acrylic acid ester and a unit derived from a conjugated diene, and the like. In addition, these polymers may have a unit derived from a crosslinkable monomer, if necessary. Above all, when a thermoplastic resin containing a (meth) acrylic resin is used, the rubber particles (II) are preferably acrylic elastic particles.

The rubber particles (II) are preferably rubber particles having a multi-layer structure, and a plurality of layers are laminated substantially concentrically from the core of the particles toward the outer shell, and the layers are bonded by graft bonding. Is more preferable.

The acrylic elastic particles, which is a preferred embodiment of the rubber particles (II), may be particles made of a monopolymer, or particles having at least two layers of polymers having different elastic moduli. .. The acrylic elastic particles are derived from a polymer having a unit derived from conjugated diene and / or an acrylic elastic polymer (for example, an acrylic acid acyclic alkyl ester) from the viewpoint of impact resistance of the thermoplastic resin molded product. It is preferable that the core-shell particles have a multilayer structure composed of a layer containing a polymer containing a unit as a main component) and a layer containing another polymer, and the layer containing an acrylic elastic polymer and its outside thereof are preferably formed. A core-shell particle having a two-layer structure composed of a layer containing a methacrylic polymer covering, or a layer containing a methacrylic polymer, a layer containing an acrylic elastic polymer covering the outside thereof, and further outside thereof. It is more preferable that the core-shell particles have a three-layer structure composed of a layer containing a methacrylic polymer to cover the polymer, and further preferably, the core-shell particles have a three-layer structure from the viewpoint of heat resistance.

The methacrylic polymer constituting the core-shell particles is preferably a polymer containing a unit derived from a methacrylic acid acyclic alkyl ester as a main component. In the methacrylic polymer, the content of the unit derived from the acyclic alkyl ester of methacrylic acid is preferably 50 to 100% by mass, preferably 80 to 100% by mass, from the viewpoint of fluidity and heat resistance. More preferred.
The acyclic alkyl ester of methacrylic acid is preferably methyl methacrylate from the viewpoint of fluidity and heat resistance, and the methacrylic polymer constituting the core-shell particles contains 80 to 100% by mass of methyl methacrylate. Is the most preferable.

The method for producing the acrylic elastic particles is not particularly limited, and the acrylic elastic particles can be produced by a method according to a known method (for example, International Publication No. 2016/121868, etc.).

The content of the acrylic elastic particles in the thermoplastic resin composition is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more, and preferably. It is 25% by mass or less, more preferably 20% by mass or less. When the content of the acrylic elastic particles is within the above range, the heat resistance of the thermoplastic resin molded product is improved.

〔Additive〕
The thermoplastic resin composition may contain additives. The types of additives are not particularly limited, and for example, ultraviolet absorbers, polymer processing aids, light stabilizers, antioxidants, heat stabilizers, lubricants, antistatic agents, pigments, dyes, matting agents, fillers. , Impact resistant aids, plasticizers and the like. One type of additive may be used alone, or two or more types may be used in combination.
The additive may be an organic compound or an inorganic compound, but an organic compound is preferable from the viewpoint of dispersibility in the thermoplastic resin composition.

The content of the additive in the thermoplastic resin composition is not particularly limited, but is preferably 0.01 to 10% by mass, more preferably 0.05 to 8% by mass, and further preferably 0.1 to 1% by mass. It is 5% by mass. When the content of the additive is not less than the lower limit value, the effect of the additive can be sufficiently exhibited, and when it is not more than the upper limit value, the physical properties originally possessed by the thermoplastic resin molded product can be sufficiently maintained.

[Melting viscosity]
The thermoplastic resin composition used in the present invention preferably has a melt viscosity of 100 to 1,500 Pa · s at a shear rate of 122 / sec at the temperature (set temperature) of the thermoplastic resin composition in the gear pump. When the melt viscosity is at least the lower limit value, the mixture can be sufficiently mixed and the temperature distribution tends to be uniform. On the other hand, when it is not more than the upper limit value, the processability of the thermoplastic resin molded product is improved. From these viewpoints, at the manufacturing temperature, the melt viscosity at a shear rate of 122 / sec is preferably 200 Pa · s or more, more preferably 300 Pa · s or more, still more preferably 400 Pa · s or more, and It is preferably 1,400 Pa · s or less, more preferably 1,300 Pa · s or less, further preferably 1,200 Pa · s or less, still more preferably 1,000 Pa · s or less, and more. More preferably, it is 800 Pa · s or less. The melt viscosity of the thermoplastic resin composition can be adjusted by adjusting the molecular weight of the thermoplastic resin (I), the acrylic ester content, and the like.
At each resin temperature (set temperature), the melt viscosity at a shear rate of 122 / sec can be measured by the method described in Examples.

<Use>
Since the thermoplastic resin molded body obtained by the manufacturing method of the present invention has few defects of foreign matter, it is used for decoration of automobiles and home appliances; polarizing element protective film, polarizing plate protective film, retardation film, brightness improving film, liquid crystal substrate, light. Optical applications such as diffusion sheets and prism sheets; can be suitably used for building materials such as wall materials, window films, window frames, bathroom wall materials, etc. In particular, polarizing element protective films, polarizing plate protective films, retardation films, etc. It is preferably used as a film such as a brightness improving film. Further, it can be suitably used as an optical molded body, a decorative molded body, and a molded body for building materials.
When the thermoplastic resin molded product is an optical molded product, the total light transmittance of the optical molded product is preferably 85% or more, more preferably 90% or more, still more preferably 92% or more.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples.

<Weight average molecular weight (Mw), number average molecular weight (Mn)>
The weight average molecular weight (Mw) and the number average molecular weight (Mn) were determined by GPC (gel permeation chromatography) in terms of standard polystyrene-equivalent molecular weight. The measuring device and conditions are as follows.
・ Equipment: GPC equipment "HLC-8320" manufactured by Tosoh Corporation
-Separation column: Directly connected "TSKgel SuperMultipore HZM-M" and "SuperHZ4000" manufactured by Tosoh Corporation-Detector: "RI-8020" manufactured by Tosoh Corporation
-Eluent: tetrahydrofuran-Eluent flow rate: 0.35 ml / min-Sample concentration: 8 mg / 10 ml
-Column temperature: 40 ° C

<Melting viscosity>
After the resin (pellet) to be measured was dried at 80 ° C. for 12 hours, the melt viscosity at each resin temperature was measured using "Capirograph 1D" manufactured by Toyo Seiki Co., Ltd. under the condition of a shear rate of 122 / sec.

<Discharge amount from die>
The resin discharged from the die was collected in 36 seconds and its weight was measured. From this result, the discharge amount per hour was calculated.

<Amount of leak resin from gear pump (GP)>
The resin leaking from the gear shaft of the gear pump was sampled for 5 minutes and its weight was measured. From this result, the amount of gear pump leak resin per hour was calculated.

<Amount of foreign matter in the film>
On a matte black cloth (manufactured by Kawashima Selkon Textiles Co., Ltd.), 10 films obtained in each Example and Comparative Example were cut out to a size of 1.4 m × 0.7 m and placed, and the vertical surface of each film surface was placed. The number of foreign substances detected due to the difference in surface unevenness when visually observed using the reflected light of the fluorescent lamp was counted and calculated as the amount of foreign substances per 1 m ² . The foreign matter here is an unevenness in which the value of width × length exceeds 0.03 mm ² .

<Manufacturing Example 1: Production of Thermoplastic Resin (I)>
Methyl methacrylate 100 parts by mass, polymerization initiator [2,2'-azobis (2-methylpropionitrile), hydrogen extraction capacity: 1%, 1 hour half-life temperature: 83 ° C] 0.1 parts by mass and chain transfer 0.21 part by mass of the agent (n-octyl mercaptan) was added and dissolved to obtain a raw material solution.
Next, 100 parts by mass of ion-exchanged water, 0.03 parts by mass of sodium sulfate and 0.45 parts by mass of a suspension dispersant were mixed to obtain a mixed solution.
420 parts by mass of the mixed solution and 210 parts by mass of the raw material solution were charged into the pressure-resistant polymerization tank, and the polymerization reaction was started at a temperature of 70 ° C. while stirring in a nitrogen atmosphere. After 3 hours from the start of the polymerization reaction, the temperature was raised to 90 ° C. and stirring was continued for 1 hour to obtain a liquid in which the beaded polymer was dispersed.
The obtained polymer dispersion was washed with an appropriate amount of ion-exchanged water, the bead polymer was taken out using a bucket centrifuge, and dried in a hot air dryer at 80 ° C. for 12 hours to form beads (meth). An atacryl resin was obtained. The weight average molecular weight Mw of the obtained (meth) acrylic resin was 110,000, and the molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) was 2.0.

<Manufacturing example 2: Production of rubber particles (II)>
A reactor equipped with a stirrer, thermometer, nitrogen gas introduction tube, monomer introduction tube and reflux condenser, 1050 parts by mass of ion-exchanged water, 0.5 parts by mass of sodium dioctyl sulfosuccinate and 0.7 mass by mass of sodium carbonate. After the parts were charged and the inside of the container was sufficiently replaced with nitrogen gas, the internal temperature was set to 80 ° C. A monomer mixture having a mass ratio of methyl methacrylate: methyl acrylate: allyl methacrylate of 94: 5.8: 0.2 after adding 0.25 parts by mass of potassium persulfate and stirring for 5 minutes. 245 parts by mass was continuously added dropwise over 50 minutes, and after completion of the addition, a polymerization reaction was further carried out for 30 minutes.
Next, 0.32 parts by mass of potassium peroxobisulfate was added to the reactor and stirred for 5 minutes, and then the mass ratio of butyl acrylate: styrene: allyl methacrylate was 80.6: 17.4: 2. 315 parts by mass of the monomer mixture was continuously added dropwise over 60 minutes, and after completion of the addition, a polymerization reaction was further carried out for 30 minutes.
Subsequently, 0.14 parts by mass of potassium peroxobisulfate was added to the reactor and stirred for 5 minutes, and then 30 parts by mass of a monomer mixture having a mass ratio of methyl methacrylate: methyl acrylate of 94: 6 was added. The particles were continuously added dropwise over a minute, and after the addition was completed, a polymerization reaction was further carried out for 60 minutes to obtain acrylic elastic particles having a three-layer structure.

<Manufacturing Example 3: Production of Thermoplastic Resin Composition>
84 parts by mass of the thermoplastic resin (I) obtained in Production Example 1, 16 parts by mass of the rubber particles (II) obtained in Production Example 2, and 2 parts by mass of an ultraviolet absorber (Adecastab LA31RG manufactured by ADEKA Co., Ltd.) A pellet of the (meth) acrylic resin composition was obtained using a twin-screw extruder with a vent having a screw diameter of 58 mm set at 260 ° C. The melt viscosity of the obtained (meth) acrylic resin composition at 270 ° C. and a shear rate of 122 / sec was 740 Pa · s.

<Example 1>
Single-screw extruder with 90 mm diameter vent (L / D = 26.0, cylinder temperature 240-260 ° C), gear pump (manufactured by Toshiba Machine Co., Ltd., model number GP-120), polymer filter (length 360 mm, diameter 60 mm candle) A film manufacturing device equipped with 4 mold filter elements, filtration accuracy of 10 μm), static mixer (number of elements = 16), and T-die in this order. From the head of the extruder, gear pump, polymer filter, static mixer. , The thermoplasticity obtained in Production Example 3 under the conditions that the set temperature up to the T-die is 270 ° C., the front pressure of the gear pump is 3 MPa, the amount of leak resin from the gear pump is 0.73 kg / hour, and the discharge amount from the die is 180 kg / hour. The resin composition is extruded, sandwiched between a mirror metal rigid body roll and a mirror metal elastic roll set at 90 ° C. at a linear pressure of 30 N / mm, passed through a transport and slit process, and has a width of 1400 mm and a thickness of 80 μm (polymer). ) An acrylic resin film (thermoplastic resin polymer) was produced.
Table 1 shows the evaluation results of the amount of foreign matter in the (meth) acrylic resin film obtained 10 hours after the start of film formation.

<Example 2>
A (meth) acrylic resin film was obtained in the same manner as in Example 1 except that the discharge amount from the die and the leak resin amount from the gear pump were as shown in Table 1. Table 1 shows the evaluation results of the amount of foreign matter in the (meth) acrylic resin film obtained 10 hours after the start of film formation.

<Example 3>
A (meth) acrylic resin film was obtained in the same manner as in Example 1 except that the set temperature from the extruder head to the T die and the amount of leak resin from the gear pump were as shown in Table 1. Table 1 shows the evaluation results of the amount of foreign matter in the (meth) acrylic resin film obtained 10 hours after the start of film formation.

<Example 4>
A (meth) acrylic resin film was obtained in the same manner as in Example 1 except that the set temperature from the extruder head to the T die and the amount of leak resin from the gear pump were as shown in Table 1. Table 1 shows the evaluation results of the amount of foreign matter in the (meth) acrylic resin film obtained 10 hours after the start of film formation.

<Example 5>
A (meth) acrylic resin film was obtained in the same manner as in Example 1 except that the amount of leak resin from the gear pump was as shown in Table 1. Table 1 shows the evaluation results of the amount of foreign matter in the (meth) acrylic resin film obtained 10 hours after the start of film formation.

<Comparative example 1>
A (meth) acrylic resin film was obtained in the same manner as in Example 5 except that the amount of leak resin in the gear pump was as shown in Table 1. Table 1 shows the evaluation results of the amount of foreign matter in the (meth) acrylic resin film obtained 10 hours after the start of film formation.

In Examples 1 to 5, the amount of foreign matter in the obtained (meth) acrylic resin film (thermoplastic resin molded product) was small because the resin retained in the gear pump could be sufficiently discharged. On the other hand, in Comparative Example 1, since the resin staying in the gear pump could not be sufficiently discharged, the amount of foreign matter in the (meth) acrylic resin film was large.

Claims (10)

A method for manufacturing a thermoplastic resin molded product by a melt extrusion method in which a gear pump is arranged between an extruder and a die, from the gear pump with respect to 100 parts by mass of a discharge amount of the thermoplastic resin composition discharged from the die. A method for producing a thermoplastic resin molded product, wherein the amount of leaked resin is 0.10 to 2.00 parts by mass. The method for producing a thermoplastic resin molded product according to claim 1, wherein a polymer filter is arranged between the gear pump and the die. The method for producing a thermoplastic resin molded product according to claim 1 or 2, wherein the temperature of the thermoplastic resin composition in the gear pump is 230 to 300 ° C. The thermoplastic according to any one of claims 1 to 3, wherein the thermoplastic resin molded product is produced under the condition that the melt viscosity of the thermoplastic resin composition at a shear rate of 122 / sec is 100 to 1,500 Pa · s. A method for manufacturing a resin molded product. The method for producing a thermoplastic resin molded product according to any one of claims 1 to 4, wherein the thermoplastic resin composition contains a (meth) acrylic resin as the thermoplastic resin (I). The (meth) acrylic resin is a homopolymer (A) of methyl methacrylate;
Acrylic ester homopolymer (B);
Copolymer of methyl methacrylate and acrylic ester (C);
A mixture of a homopolymer of methyl methacrylate (A) and a homopolymer of an acrylic ester (B);
A mixture of a homopolymer of methyl methacrylate (A) and a copolymer of methyl methacrylate and an acrylic acid ester (C);
The method for producing a thermoplastic resin molded product according to claim 5, which is at least one selected from the above. The method for producing a thermoplastic resin molded product according to any one of claims 1 to 6, wherein the thermoplastic resin composition contains rubber particles (II). The method for producing a thermoplastic resin molded product according to claim 7, wherein the rubber particles (II) are acrylic elastic particles. The method for producing a thermoplastic resin molded product according to any one of claims 1 to 8, wherein the thermoplastic resin molded product is a film. The production of the thermoplastic resin molded product according to any one of claims 1 to 8, wherein the thermoplastic resin molded product is one selected from an optical molded product, a decorative molded product, and a building material molded product. Method.