JP7185125B2 - Molded body manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin for extrusion molding and a method for producing a molded article.

Patent Literature 1 discloses a method of extruding a mixed resin of polypropylene and polyethylene to form a resin sheet and using the resin sheet to manufacture a resin panel.

JP 2015-51581 A

By the way, when the inventor of the present invention examined the resin panel of Patent Document 1, there were problems such as scratches on the surface of the resin panel being conspicuous because the glossiness of the resin panel was too high. I noticed

The present invention has been made in view of such circumstances, and provides an extrusion molding resin capable of reducing the glossiness of a molded product.

According to the present invention, there is provided an extrusion molding resin comprising component A, component B, and component C, wherein component A is polypropylene (hereinafter “PP”), and component B is a low It is a density polyethylene (hereinafter "LDPE"), the component C is a high density polyethylene (hereinafter "HDPE"), and the component C has a melt flow rate of 0.16 when measured at 190°C and 2.16 kg. An extrusion resin is provided that is 10-1.00 g/10 min.

As a result of intensive studies, the inventors of the present invention found that the glossiness of the molded product can be reduced by using a resin containing the above components A to C as the resin for extrusion molding, and completed the present invention. arrived.

Various embodiments of the present invention are illustrated below. The embodiments shown below can be combined with each other.
Preferably, the resin for extrusion molding described above, wherein the component A has a melt flow rate of 0.10 to 5.00 g/10 minutes measured at 190° C. and 2.16 kg. be.
Preferably, the resin for extrusion molding described above, wherein the component B is an extrusion molding resin having a melt flow rate of 0.10 to 10.00 g/10 minutes measured at 190° C. and 2.16 kg. be.
Preferably, in the resin for extrusion molding described above, the mass ratio of the component B to the component A is 0.10 to 0.50, and the mass ratio of the component C to the component A is 0.10 to 0.50. 10 to 0.50 for extrusion molding.
According to another aspect of the present invention, there is provided a method for producing a molded article, comprising the step of extruding a molten resin obtained by melt-kneading the extrusion-molding resin described above in an extruder.
Preferably, the method as described above, comprising forming a parison by said extrusion and shaping said parison.
Preferably, the method as described above, wherein the molding of the parison is blow molding or vacuum molding.

An example of a molding machine 1 that can be used in the method for manufacturing a molded article according to one embodiment of the present invention is shown.

Embodiments of the present invention will be described below. Various features shown in the embodiments shown below can be combined with each other. In addition, the invention is established independently for each characteristic item.

1. Extrusion Molding Resin The extrusion molding resin of one embodiment of the present invention contains Component A, Component B, and Component C. The extrusion molding resin may contain only components A to C, or may contain resins other than components A to C. When resins other than components A to C are included, the content thereof is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, relative to the total resin.

Each component will be described in detail below. In the following description, polypropylene is abbreviated as PP, low-density polyethylene as LDPE, high-density polyethylene as HDPE, and melt flow rate as MFR. Unless otherwise specified, MFR means a value measured at 190°C and 2.16 kg by a method based on JIS K7210:1999. MFR of PP means a value measured at 230°C and 2.16 kg.

<Component A: PP>
Component A is PP. PP includes homo PP, block PP, random PP and the like, and homo PP is preferable. The method for producing PP is not particularly limited, but it can be produced, for example, by a slurry method.

The MFR of component A is not particularly limited, but is preferably 0.10 to 5.00 g/10 minutes, more preferably 0.30 to 2.00 g/10 minutes. Specifically, MFR is, for example, 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 2 .00, 3.00, 4.00, 5.00 g/10 min, and may be in the range between any two of the values exemplified herein.

<Component B: LDPE>
Component B is LDPE. The density (g/cm ³ ) of LDPE is 0.910 or more and less than 0.930, preferably 0.915 or more and 0.925 or less. Specifically, this density is, for example, 0.910, 0.915, 0.920, 0.925, 0.929. good. The MFR of component B is not particularly limited, but is preferably 0.10 to 10.00 g/10 minutes, more preferably 0.30 to 2.00 g/10 minutes. Specifically, MFR is, for example, 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 2 .00, 3.00, 4.00, 5.00, 6.00, 7.00, 8.00, 9.00, 10.00 g/10 min. It may be in the range between.

The mass ratio of component B to component A is preferably 0.10 to 0.50, more preferably 0.15 to 0.40. Specifically, this mass ratio is specifically, for example, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0 .50 and may be in the range between any two of the numbers exemplified herein. and may be in a range between any two of the numerical values exemplified here.

<Component C: HDPE>
Component C is HDPE. HDPE has a density (g/cm ³ ) of 0.942 or more, preferably 0.942 or more and 0.965 or less. Specifically, this density is, for example, 0.942, 0.945, 0.950, 0.955, 0.960, 0.965, and within a range between any two of the numerical values exemplified here may be The MFR of component C is between 0.10 and 1.00 g/10 min, preferably between 0.20 and 0.80 g/10 min. Specifically, MFR is, for example, 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00 g/10 minutes and may be in the range between any two of the numbers exemplified herein.

The mass ratio of component C to component A is preferably 0.10 to 0.50, more preferably 0.15 to 0.40. Specifically, this mass ratio is specifically, for example, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0 .50 and may be in the range between any two of the numbers exemplified herein. and may be in a range between any two of the numerical values exemplified here.

2. Method for Producing Molded Article A method for producing a molded article according to an embodiment of the present invention comprises a step of extrusion-molding a molten resin obtained by melt-kneading the extrusion-molding resin described above in an extruder.

The method of this embodiment can be carried out using, for example, a molding machine 1 illustrated in FIG. The molding machine 1 includes a resin supply device 2 , a head 18 and a split mold 19 . The resin supply device 2 includes a hopper 12 , an extruder 13 and an accumulator 17 . The extruder 13 and the accumulator 17 are connected via a connecting pipe 25 . The accumulator 17 and the head 18 are connected via a connecting pipe 27 .
Each configuration will be described in detail below.

<Hopper 12, Extruder 13>
The hopper 12 is used to charge the raw material resin 11 into the cylinder 13 a of the extruder 13 . Although the form of the raw material resin 11 is not particularly limited, it is usually in the form of pellets. The raw material resin is the resin for extrusion molding described above.

The raw material resin 11 is fed from the hopper 12 into the cylinder 13a, and then heated in the cylinder 13a to be melted into a molten resin. Further, it is conveyed toward the tip of the cylinder 13a by the rotation of the screw arranged in the cylinder 13a. The screw is arranged in the cylinder 13a, and conveys the molten resin while kneading it by its rotation. A gear device is provided at the proximal end of the screw, and the screw is rotationally driven by the gear device.

<Accumulator 17, Head 18>
The molten resin is extruded from the resin extrusion port of the cylinder 13 a and injected into the accumulator 17 through the connecting pipe 25 . The accumulator 17 has a cylinder 17a and a piston 17b slidable inside the cylinder 17a, and resin can be stored in the cylinder 17a. By moving the piston 17b after a predetermined amount of resin is stored in the cylinder 17a, the resin is pushed out through the slit provided in the head 18 through the connecting pipe 27 and suspended to form the parison 23. Thus, the parison 23 is formed by extrusion molding of molten resin. The shape of the parison 23 is not particularly limited, and may be cylindrical or sheet-like. The accumulator 17 may be built in the head 18, and may push down the piston 17b in the vertical direction. The accumulator 17 may be omitted if unnecessary.

<Split mold 19>
The parison 23 is guided between the pair of split molds 19 . A compact is obtained by molding the parison 23 using the split mold 19 . The method of molding using the split mold 19 is not particularly limited, and may be blow molding in which air is blown into the cavity of the split mold 19 for molding. may be vacuum forming in which the parison 23 is formed under reduced pressure, or a combination thereof. In the case of blow molding, air is blown in a pressure range of 0.05 to 0.15 MPa, for example.

In the above-described embodiment, molding using the split mold 19 is performed before the parison 23 is cooled. good.

1. Manufacture of Molded Body Using the molding machine 1 shown in FIG. 1, a resin was extruded to prepare a molded body. As the extruder 13, an electric small hollow molding machine "JEB-7" manufactured by Japan Steel Works, Ltd. was used. A full flight screw with a pin was used, and L/D was set to 26.5. The diameter of the die core was Φ34 for the die and Φ40 for the core. The temperature was 230° C. and the screw speed was 36 rpm. As raw material resins, resins blended at blending ratios shown in Tables 1 to 3 were used. Also, 1.0 parts by weight of LLDPE base masterbatch containing 40 wt % of carbon black as a coloring agent was added to 100 parts by weight of the resin.

After placing the parison 23 formed under the above conditions between the split molds 19, the split molds 19 are clamped, and air is blown for 15 seconds at a pressure of 0.5 Pa to reduce the dimensions to 60 mm x 80 mm x. A substantially rectangular parallelepiped hollow molded body of 230 mm was produced.

2. Evaluation Glossiness (gloss value) was measured for the produced molding. Glossiness was measured on a flat portion of the side surface (60 mm×230 mm dimension) of the molded article under the following measurement conditions. The glossiness of each molded article was measured at 5 points, and the average value was taken as the glossiness of the molded article. The results are shown in Tables 1-3.

<Glossiness measurement conditions>
Gloss meter: Handy gloss meter PG-1 manufactured by Nippon Denshoku Industries Co., Ltd.
Measurement angle: 60°
Optical system: JIS Z 8741, ISO 2813, ASTM D 523, DIN 67530 compliant Light source: Tungsten lamp Detector: Photodiode Measurement size: 10.0 x 20.0 mm

Details of the resins used in Tables 1 to 3 are as follows.

<PP>
EC9: Novatec PP, manufactured by Japan Polypropylene Corporation

<LDPE>
M2170: Suntech-LD, manufactured by Asahi Kasei Corporation M1820: Suntech-LD, manufactured by Asahi Kasei Corporation F108-1: Sumikasen, manufactured by Sumitomo Chemical Co., Ltd.

<HDPE>
J240: Suntech-HD, manufactured by Asahi Kasei Corporation A260: Suntech-HD, manufactured by Asahi Kasei Corporation B970: Suntech-HD, manufactured by Asahi Kasei Corporation B980: Suntech-HD, manufactured by Asahi Kasei Corporation

As shown in Table 1, when PP, LDPE, and HDPE are included, and the MFR of HDPE is 0.10 to 1.00 g/10 min, the gloss value is as low as 5.4 to 6.1. Met. Further, as shown in Examples 1 to 6, even when the MFR of LDPE was changed, the glossiness did not change significantly.

As shown in Comparative Examples 1 to 8 in Table 2, when any one of PP, LDPE, and HDPE was lacking, the gloss values were as high as 6.9 to 11.2. Further, as shown in Comparative Examples 9 to 14 in Table 3, even when PP, LDPE, and HDPE are included, when the MFR of HDPE exceeds 1.00, the glossiness is 7.4 to 8. It was a high value of 0.5.

From the above, it was demonstrated that glossiness is reduced when PP, LDPE, and HDPE are included and the MFR of HDPE is 0.10 to 1.00 g/10 min.

Reference Signs List 1: molding machine 2: resin supply device 10: duct 11: raw resin 12: hopper 13: extruder 13a: cylinder 17: accumulator 17a: cylinder 17b: piston 18: head 19: split mold 23: parison 25: connecting pipe 27: connecting pipe

Claims (1)

A step of extruding a molten resin obtained by melt-kneading a resin for extrusion molding in an extruder;
A method for producing a molded body, comprising the step of forming a parison by the extrusion molding and blow molding the parison using a mold before the parison is cooled,
The extrusion molding resin contains component A, component B, and component C,
The component A is polypropylene,
The component B is low density polyethylene,
The component C is high density polyethylene,
The component A has a melt flow rate of 0.10 to 1.00 g/10 minutes measured at 230° C. and 2.16 kg,
The component B has a melt flow rate of 1.00 to 3.00 g/10 minutes measured at 190° C. and 2.16 kg,
The component C has a melt flow rate measured at 190° C. and 2.16 kg of 0.20 to 0.30 g/10 minutes or less,
The mass ratio of the component B to the component A is 0.20 to 0.30 ,
The method, wherein the mass ratio of said component C to said component A is 0.20 to 0.30 .

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