JP2022053734A - Thermoplastic resin molded member and its surface processing method, thermoplastic resin molding die and its surface processing method - Google Patents

Abstract

To provide a thermoplastic resin molded member that can reduce the incidence of defective products.SOLUTION: The thermoplastic resin molded member of the present invention is, for example, a mold or an injection member, the surface of at least the thermoplastic resin flow path exhibits an arithmetic mean roughness Ra in the range of 0.1 μm to 0.5 μm inclusive and a maximum height Rz in the range of 0.5 μm to 5.5 μm inclusive. The melted thermoplastic resin flows in the thermoplastic resin flow path.SELECTED DRAWING: None

Description

The present invention relates to a thermoplastic resin molded member, particularly a thermoplastic resin molded member having a resin flow path portion. The present invention also relates to a method for surface processing a thermoplastic resin molded member. Furthermore, the present invention relates to a thermoplastic resin molded mold. The present invention also relates to a method for processing a parting surface of a thermoplastic resin molded split mold.

In the past, it has been proposed to "form a wall surface in contact with a resin in a runner of a resin-sealed mold in a rough surface shape" (see, for example, Japanese Patent Application Laid-Open No. 62-140426). By forming the wall surface of the runner in a rough surface shape in this way, the temperature distribution of the transfer resin can be made uniform, and the transfer of the resin to the cavity can be facilitated as well as the cavity. The inflow of air bubbles into the plastic can be reduced.

Japanese Unexamined Patent Publication No. 62-140426

By the way, it cannot be said that the generation of defective products due to the generation of weld lines, bubbles (voids), shorts, burrs, burning, and gate residue has been sufficiently reduced in the field of thermoplastic resin molding.

An object of the present invention is to provide a thermoplastic resin molded member capable of reducing the occurrence rate of defective products.

The thermoplastic resin molding member according to the first aspect of the present invention is, for example, a member such as a mold or an injection member, and the surface of at least the surface of the thermoplastic resin flow path portion is within the range of 0.1 μm or more and 0.5 μm or less. The arithmetic mean roughness Ra of the above is shown, and the maximum height Rz in the range of 0.5 μm or more and 5.5 μm or less is shown. It is preferable that the surface of the thermoplastic resin flow path portion shows an arithmetic average roughness Ra in the range of 0.15 μm or more and 0.45 μm or less. Further, the surface of the thermoplastic resin flow path portion preferably shows a maximum height Rz in the range of 1.0 μm or more and 5.5 μm or less, and a maximum height Rz in the range of 1.5 μm or more and 5.5 μm or less. It is more preferable to show.

As a result of diligent studies by the inventor of the present application, when a thermoplastic resin is molded using a thermoplastic resin molding member having the above-mentioned roughness on the surface of the thermoplastic resin flow path portion, weld lines, bubbles (voids), shorts, etc. It has been clarified that the generation of burrs, burning, gate residue, etc. is suppressed, and as a result, the generation rate of defective products can be reduced and the life of the thermoplastic resin molded member can be extended.

The method according to the second aspect of the present invention is a method of applying surface processing, in which the surface of the thermoplastic resin flow path portion of the thermoplastic resin molding member is within the range of 0.1 μm or more and 0.5 μm or less. The surface of the thermoplastic resin flow path portion of the thermoplastic resin molding member is processed so as to show the arithmetic average roughness Ra and the maximum height Rz within the range of 0.5 μm or more and 5.5 μm or less. It is preferable that the surface of the thermoplastic resin flow path portion shows an arithmetic average roughness Ra in the range of 0.15 μm or more and 0.45 μm or less. Further, the surface of the thermoplastic resin flow path portion preferably shows a maximum height Rz in the range of 1.0 μm or more and 5.5 μm or less, and a maximum height Rz in the range of 1.5 μm or more and 5.5 μm or less. It is more preferable to show.

As a result of diligent studies by the inventor of the present application, when a thermoplastic resin is molded using the thermoplastic resin molding member having the above-mentioned surface processing applied to the thermoplastic resin flow path portion, weld lines, bubbles (voids), shorts, and burrs are found. It has been clarified that the generation, burning, generation of gate residue, etc. are suppressed, and as a result, the generation rate of defective products can be reduced and the life of the thermoplastic resin molded member can be extended.

The method according to the third aspect of the present invention is the method according to the second aspect, and the surface treatment is performed by at least one of a shot peening treatment and a blast treatment.

Therefore, in this method, the surface processing can be performed by appropriately adjusting the specific gravity, particle size, hardness, collision speed, collision angle, etc. of the shot or the abrasive.

The method according to the fourth aspect of the present invention is the method according to the second aspect, and the surface treatment is performed by a polishing treatment and at least one of a shot peening treatment and a blast treatment carried out thereafter.

Here, the polishing process is performed before at least one of the shot peening process and the blast process is performed. Therefore, in this method, when the surface condition of the thermoplastic resin flow path portion of the thermoplastic resin molding member to be processed is not good, at least one of the shot peening treatment and the blast treatment is performed after the surface condition is improved by polishing treatment. Can be processed.

The thermoplastic resin molded split mold according to the fifth aspect of the present invention shows, for example, an arithmetic mean roughness Ra in the range of at least 0.1 μm or more and 0.5 μm or less on the parting surface, and 0.5 μm or more and 5.5 μm. The maximum height Rz within the following range is shown. The parting surface preferably shows an arithmetic mean roughness Ra in the range of 0.15 μm or more and 0.45 μm or less. Further, the parting surface preferably shows a maximum height Rz in the range of 1.0 μm or more and 5.5 μm or less, and more preferably shows a maximum height Rz in the range of 1.5 μm or more and 5.5 μm or less. ..

By the way, when a thermoplastic resin is molded using a split mold, gas stains often adhere to the parting surface. Then, if the gas stains are accumulated, the shape of the cavity may gradually change, which is not preferable. Therefore, as a result of diligent studies by the inventor of the present application, when the thermoplastic resin is molded by using the thermoplastic resin molding mold having the above-mentioned roughness of the parting surface, the gas discharge property is improved, and as a result, the gas is discharged. It became clear that dirt can be reduced.

The method according to the sixth aspect of the present invention is a method of applying surface processing, in which the arithmetic average coarseness of the parting surface of the thermoplastic resin molded split mold is within the range of 0.1 μm or more and 0.5 μm or less. The parting surface of the thermoplastic resin molded split mold is machined so as to show Ra and a maximum height Rz within the range of 0.5 μm or more and 5.5 μm or less. The parting surface preferably shows an arithmetic mean roughness Ra in the range of 0.15 μm or more and 0.45 μm or less. Further, the parting surface preferably shows a maximum height Rz in the range of 1.0 μm or more and 5.5 μm or less, and more preferably shows a maximum height Rz in the range of 1.5 μm or more and 5.5 μm or less. ..

As a result of diligent studies by the inventor of the present application, when the thermoplastic resin is molded by using the thermoplastic resin molding mold having the above-mentioned roughness of the parting surface, the gas discharge property is improved, and as a result, gas stains are removed. It became clear that it can be reduced.

The method according to the seventh aspect of the present invention is the method according to the sixth aspect, and the processing of the parting surface is performed by at least one of a shot peening process and a blast process.

Therefore, in this method, the surface of the parting surface can be processed by appropriately adjusting the specific gravity, particle size, hardness, collision speed, collision angle, etc. of the shot or the abrasive.

The method according to the eighth aspect of the present invention is the method according to the sixth aspect, and the processing of the parting surface is performed by a polishing treatment and at least one of a shot peening treatment and a blasting treatment carried out thereafter. To.

Here, the polishing process is performed before at least one of the shot peening process and the blast process is performed. Therefore, in this method, when the condition of the parting surface of the thermoplastic resin molded split mold to be processed is not good, at least one of the shot peening treatment and the blast treatment is performed after the condition of the parting surface is improved by polishing treatment. Can be processed.

-First Embodiment-
The thermoplastic resin molding member according to the first embodiment of the present invention is, for example, a member such as a mold or an injection member, and the surface of at least the surface of the thermoplastic resin flow path portion is in the range of 0.1 μm or more and 0.5 μm or less. The arithmetic mean roughness Ra in the range is shown, and the maximum height Rz in the range of 0.5 μm or more and 5.5 μm or less is shown. The arithmetic average roughness Ra of the surface of the thermoplastic resin flow path portion is preferably in the range of 0.15 μm or more and 0.45 μm or less. Further, the maximum height Rz of the surface of the thermoplastic resin flow path portion is preferably in the range of 1.0 μm or more and 5.5 μm or less, and more preferably in the range of 1.5 μm or more and 5.5 μm or less. .. Further, here, the thermoplastic resin flow path portion is a portion through which the thermoplastic resin melted by heat flows, and is, for example, a sprue bush portion, a runner portion, a gate portion, or the like. Further, the thermoplastic resin referred to here is, for example, polyamide, polycarbonate, polybutylene terephthalate, polyethylene terephthalate, syndiotactic polystyrene, polyphenylene sulfide, liquid crystal polymer, polymethyl methacrylate, polyacrylic acid ester, polyvinyl chloride, polystyrene. , Polycarbonate, polyethylene, polypropylene, ABS resin, fluororesin and the like.

By the way, the thermoplastic resin molded member according to the first embodiment of the present invention is manufactured through a roughening step. If necessary, the pretreatment step may be carried out before the roughening step, or the post-treatment step (for example, a surface smoothing step or the like) may be carried out after the roughening step. Hereinafter, these steps will be described in detail.

(1) Roughening Step In the roughening step, for example, at least one of a shot peening treatment and a blast treatment is carried out on the thermoplastic resin flow path portion of the thermoplastic resin molding member.

In the shot peening treatment, spherical particles corresponding to the finished surface roughness are collided with compressed air at high speed on the thermoplastic resin flow path portion, and circular pore-shaped or protruding unevenness is formed on the surface thereof. Here, the spherical particles are preferably steel balls. Further, the diameter of the spherical particles and the pressure of the compressed air are set so that, for example, the arithmetic mean roughness Ra of the finished surface is within the range of 0.1 μm or more and 0.3 μm or less, and the maximum height Rz is 1.0 μm or more. When it is within the range of 5 μm or less, it is preferably within the range of 50 μm or more and 100 μm or less and 0.2 MPa, and the arithmetic mean roughness Ra of the finished surface is within the range of 0.2 μm or more and 0.4 μm or less and the maximum. When the height Rz is within the range of 1.5 μm or more and 3.0 μm or less, it is preferably within the range of 50 μm or more and 100 μm or less and 0.3 MPa, and the arithmetic mean roughness Ra of the finished surface is 0.3 μm or more and 0. When the maximum height Rz is within the range of 2.5 μm or less and the maximum height Rz is within the range of 2.0 μm or more and 3.5 μm or less, it is preferably within the range of 100 μm or more and 150 μm or less and 0.2 MPa. When the average roughness Ra is within the range of 0.4 μm or more and 0.5 μm or less and the maximum height Rz is within the range of 2.5 μm or more and 4.0 μm or less, the range is 100 μm or more and 150 μm or less and 0.3 MPa. Is preferable. Further, the projection angle of the spherical particles is preferably in the range of 60 ° or more and 90 ° or less with respect to the surface of the thermoplastic resin flow path portion, and the treatment time is preferably in the range of 15 minutes or more and 30 minutes or less. preferable.

In the blast treatment, polygonal particles or spherical particles depending on the finished surface roughness are collided with compressed air at high speed on the thermoplastic resin flow path portion, and circular pore-like or protrusion-like irregularities are formed on the surface. .. Here, the particles are preferably ceramic particles. The diameter of the spherical particles and the pressure of the compressed air are such that the arithmetic mean roughness Ra of the finished surface is within the range of 0.1 μm or more and 0.3 μm or less, and the maximum height Rz is 1.0 μm or more and 2.5 μm or less. When it is within the range of, it is preferably within the range of 20 μm or more and 50 μm or less and 0.4 MPa, and the arithmetic mean roughness Ra of the finished surface is within the range of 0.2 μm or more and 0.4 μm or less and the maximum height. When Rz is in the range of 1.5 μm or more and 3.0 μm or less, it is preferably in the range of 20 μm or more and 50 μm or less and 0.4 MPa, and the arithmetic mean roughness Ra of the finished surface is 0.3 μm or more and 0.5 μm. When the maximum height Rz is within the range of 2.0 μm or more and 3.5 μm or less, it is preferably within the range of 20 μm or more and 50 μm or less and 0.3 MPa, and the arithmetic mean roughness of the finished surface is preferable. When Ra is in the range of 0.4 μm or more and 0.5 μm or less and the maximum height Rz is in the range of 2.5 μm or more and 4.0 μm or less, it is set in the range of 20 μm or more and 50 μm or less and 0.3 MPa. Is preferable. Further, the projection angle of the particles is preferably in the range of 60 ° or more and 90 ° or less with respect to the surface of the thermoplastic resin flow path portion, and the treatment time is preferably in the range of 15 minutes or more and 30 minutes or less. ..

(2) Pretreatment Step The pretreatment step is preferably performed when the arithmetic mean roughness Ra of the surface of the thermoplastic resin flow path portion of the thermoplastic resin molding member is 1.0 μm or more. This is to obtain a surface having a desired roughness in the roughening step of the subsequent step. Examples of the pretreatment include a polishing treatment such as special polishing. In the special polishing process, particles in which fine abrasive grains are laminated on an elastic core material such as resin or rubber are slid by compressed air or centrifugal force in the thermoplastic resin flow path portion, and are formed by cutting or polishing. Unevenness marks are removed and surface roughness is reduced. Here, the particles are preferably particles in which a resin core is coated with abrasive grains. The diameter of the core is preferably in the range of 0.1 mm or more and 0.8 mm or less, the diameter of the abrasive grains is preferably in the range of 1 μm or more and 8 μm or less, and the pressure of the compressed air is 0.2 MPa. It is preferably in the range of 0.5 MPa or less. Further, the projection angle of the particles is preferably in the range of 45 ° or more and 60 ° or less with respect to the surface of the thermoplastic resin flow path portion, and the treatment time is preferably in the range of 30 minutes or more and 45 minutes or less. ..

(3) Post-treatment step The post-treatment step is a step for adjusting the surface having a desired roughness at a fine level, and is performed for the purpose of polishing convex portions or removing roughness, for example. Examples of the post-processing include special blast processing and the like. In the special blast treatment, particles coated with fine abrasive grains on an elastic core material are slid on the thermoplastic resin flow path by compressed air or centrifugal force, and uneven marks formed by cutting or polishing are removed. Surface roughness is reduced. Here, it is preferable that the particles are rubber or resin cores coated with abrasive grains. Further, the diameter of the core is preferably in the range of 0.1 mm or more and 1.0 mm or less, and the diameter of the abrasive grains is preferably in the range of 1 μm or more and 5 μm or less. Further, when the particles are sprayed with compressed air, the pressure of the compressed air is preferably 0.3 MPa. Further, the projection angle of the particles is preferably in the range of 45 ° or more and 60 ° or less with respect to the surface of the thermoplastic resin flow path portion, and the treatment time is preferably in the range of 30 minutes or more and 45 minutes or less. ..

<Characteristics of the thermoplastic resin molded member according to the first embodiment of the present invention>
When the thermoplastic resin is molded by the thermoplastic resin molding member according to the first embodiment of the present invention, the generation of weld lines, bubbles (voids), shorts, burrs, burning, gate residue, etc. is suppressed, and as a result, the generation is suppressed. The rate of defective products can be reduced.

-Second Embodiment-
The thermoplastic resin molded mold according to the second embodiment shows an arithmetic mean roughness Ra in the range of at least 0.1 μm or more and 0.5 μm or less on the parting surface, and is in the range of 0.5 μm or more and 5.5 μm or less. Indicates the maximum height Rz of. The arithmetic average roughness Ra of the parting surface is preferably in the range of 0.15 μm or more and 0.45 μm or less. Further, the maximum height Rz of the parting surface is preferably in the range of 1.0 μm or more and 5.5 μm or less, and more preferably in the range of 1.5 μm or more and 5.5 μm or less.

By the way, the thermoplastic resin molded split mold according to the second embodiment of the present invention is manufactured through a roughening step. If necessary, the pretreatment step may be carried out before the roughening step, or the post-treatment step (for example, a surface smoothing step or the like) may be carried out after the roughening step. The roughening step, the pretreatment step, and the posttreatment step are the same as the roughening step, the pretreatment step, and the posttreatment step according to the first embodiment, except that the surface treatment target is the parting surface. Therefore, the description thereof will be omitted.

<Characteristics of the thermoplastic resin molded split mold according to the second embodiment of the present invention>
When the thermoplastic resin is molded by the thermoplastic resin molding mold according to the second embodiment of the present invention, the gas discharge property is improved, and as a result, gas contamination can be reduced.

Hereinafter, Examples and Comparative Examples will be shown to explain the present invention in more detail, but the present invention is not limited to this Example.

1. 1. Surface treatment of the runner part surface and parting surface of the thermoplastic resin molded split mold Special polishing treatment, shot peening treatment, blasting treatment and special blasting treatment are applied to the runner part surface and parting surface of the thermoplastic resin molded split mold. By applying in this order, the surface structure of the runner portion of the desired thermoplastic resin molded split mold was obtained.

The special polishing treatment was carried out as a pretreatment. In the special polishing process, particles coated with a resin core material having a 50% average particle size (median diameter) of 0.5 mm and abrasive grains having a 50% average particle size (median diameter) of 2 μm are coated with 0.4 MPa compressed air. , The surface of the runner portion and the parting surface of the thermoplastic resin molded split mold (dimensions: depth 250 mm × width 150 mm, material: SKD11, hardness: HRC58) were projected at a projection angle of 45 ° for 10 minutes.

In the shot peening treatment, a steel ball having a 50% average particle size (median diameter) of 50 μm is subjected to specially polished runner site surface and parting surface with compressed air of 0.4 MPa at a projection angle of 90 ° for 2 minutes. Projected.

In the blasting process, ceramic particles with a 50% average particle size (median diameter) of 50 μm are projected with 0.4 MPa compressed air onto the surface of the runner site and the parting surface that have been shot peened at a projection angle of 90 ° for 2 minutes. bottom.

The special blast treatment was performed as a post-treatment. In the special blast treatment, particles coated with abrasive grains having a 50% average particle size (median diameter) of 2 μm on a resin core material having a 50% average particle size (median diameter) of 0.5 mm are coated with compressed air of 0.2 MPa. , The surface of the runner site and the parting surface that had been blasted were projected at a projection angle of 45 ° for 10 minutes.

2. 2. Surface analysis of runner site surface and parting surface (1) Arithmetic mean roughness Ra measurement The arithmetic average roughness Ra of multiple sections of the runner site surface and parting surface described above was measured according to JIS B 0601-2001. The value was 0.180 μm.

(2) Measurement of maximum height Rz When the maximum height Rz of a plurality of sections of the runner site surface and the parting surface of the above-mentioned thermoplastic resin molded split mold was measured according to JIS B 0601-2001, the value was 1.621 μm. Met.

(3) Spiral flow test The same surface treatment as described above was applied to the groove surface of the mold (width 130 mm × depth 130 mm) in which a spiral groove having a width of 3 mm and a depth of 4 mm was formed. Then, under the conditions shown below, polyamide 6T (nylon 66) was injected from the injection molding machine into the groove of the mold through the center hole of the mold for 2 seconds, then cooled for 4 seconds, and formed in the groove. When the length of the spiral resin molded product was measured, the length was 203 mm and the peak pressure was 18.2 MPa. During this test, the temperature of the mold was kept at 80 ° C.

-Mold temperature: 80 ° C
-Resin temperature: 270 ° C
・ Filling speed: 100 mm / sec ・ Injection time: 2 seconds ・ Cooling time: 4 seconds ・ Weighing: 15.00 mm
・ Holding pressure: 0.3MPa
・ Limit speed: 10.0 mm / sec ・ Limit pressure: 5.0 MPa
・ Decompression speed: 10.0mm / sec ・ Decompression position: 3.00mm
・ Screw rotation slow speed: 0%
・ Screw rotation throw distance: 0.00mm
・ Screw back pressure: 10.0 MPa
・ Screw rotation speed: 80%

(4) Molding test of thermoplastic resin When injection molding of polyamide 6T was performed using the thermoplastic resin molding mold obtained as described above, an unsurface-treated thermoplastic resin molding mold (Comparative Example 1). Not only was the incidence of weld lines and burns reduced compared to (see), but also split-mold gas contamination was reduced.

1. 1. Surface treatment of runner part surface and parting surface of thermoplastic resin molding split mold The dimensions of the split mold are 150 mm in depth x 150 mm in width, the projection time of particles in special polishing treatment is 8 minutes, and the pressure of compressed air in shot peening treatment. The projection time of the steel ball is 1.5 minutes, the projection time of the ceramic particles in the blast treatment is 1.5 minutes, the pressure of the compressed air in the special blast treatment is 0.3 MPa, and the particles. The surface of the runner portion and the parting surface of the thermoplastic resin molded split mold were surface-treated in the same manner as in Example 1 except that the projection time was set to 6 minutes.

2. 2. Surface analysis of runner site surface and parting surface (1) Arithmetic mean roughness Ra measurement The arithmetic average roughness Ra of multiple sections of the runner site surface and parting surface described above was measured according to JIS B 0601-2001. The value was 0.238 μm.

(2) Measurement of maximum height Rz When the maximum height Rz of a plurality of sections of the runner site surface and the parting surface of the above-mentioned thermoplastic resin molded split mold was measured according to JIS B 0601-2001, the value was 2.183 μm. Met.

(3) Molding test of thermoplastic resin When injection molding of polybutylene terephthalate was performed using the thermoplastic resin molding mold obtained as described above, an unsurface-treated thermoplastic resin molding mold (Comparative Example). Not only the generation rate of bubbles was reduced as compared with 1), but also the gas contamination of the split mold was reduced.

1. 1. Surface treatment of runner part surface and parting surface of thermoplastic resin molding split mold The dimensions of the split mold are 200 mm in depth x 150 mm in width, and the material is HPM-31 (hardness: HRC58), and the projection time of particles in the special polishing treatment. The order of shot peening treatment and blast treatment was changed to 15 minutes, and in the blast treatment, ceramic particles having a 50% average particle size (median diameter) of 20 μm were treated with compressed air of 0.4 MPa and specially polished runner parts. A runner that has been blasted with compressed air of 0.2 MPa on a steel ball with a 50% average particle size (median diameter) of 100 μm in a shot peening process by projecting onto the surface and parting surface at a projection angle of 90 ° for 3 minutes. Same as Example 1 except that the surface of the site and the parting surface are projected at a projection angle of 90 ° for 3 minutes, the pressure of the compressed air in the special blast treatment is 0.3 MPa, and the projection time of the particles is 15 minutes. The surface of the runner part and the parting surface of the thermoplastic resin molded split mold were surface-treated.

2. 2. Surface analysis of runner site surface and parting surface (1) Arithmetic mean roughness Ra measurement The arithmetic average roughness Ra of multiple sections of the runner site surface and parting surface described above was measured according to JIS B 0601-2001. The value was 0.291 μm.

(2) Measurement of maximum height Rz When the maximum height Rz of a plurality of sections of the runner site surface and the parting surface of the above-mentioned thermoplastic resin molded split mold was measured according to JIS B 0601-2001, the value was 2.993 μm. Met.

(3) Molding test of thermoplastic resin When injection molding of polyphenylene sulfide was performed using the thermoplastic resin molding mold obtained as described above, an unsurface-treated thermoplastic resin molding mold (Comparative Example 1). Not only the rate of burr generation was reduced compared to (see), but also the gas contamination of the split mold was significantly reduced.

1. 1. Surface treatment of runner part surface and parting surface of thermoplastic resin molding split mold The dimensions of the split mold are 50 mm in depth x 20 mm in width, the material is STAVAX (hardness: HRC52), and the projection time of particles in the special polishing treatment is 5. The order of shot peening treatment and blast treatment was changed, and in the blast treatment, ceramic particles with a 50% average particle size (median diameter) of 20 μm were treated with 0.4 MPa of compressed air to the surface of the runner site and the specially polished runner site. A steel ball with a 50% average particle size (median diameter) of 50 μm is projected onto the parting surface at a projection angle of 90 ° for 1 minute, and the surface of the runner site that has been blasted with 0.2 MPa of compressed air. And the surface of the runner site and the party of the thermoplastic resin molded split mold as in Example 1 except that the projection was performed on the parting surface at a projection angle of 90 ° for 1 minute and the projection time of the particles in the special blasting treatment was 3 minutes. The surface of the polishing surface was treated.

2. 2. Surface analysis of runner site surface and parting surface (1) Arithmetic mean roughness Ra measurement The arithmetic average roughness Ra of multiple sections of the runner site surface and parting surface described above was measured according to JIS B 0601-2001. The value was 0.291 μm.

(2) Measurement of maximum height Rz When the maximum height Rz of a plurality of sections of the runner site surface and the parting surface of the above-mentioned thermoplastic resin molded split mold was measured according to JIS B 0601-2001, the value was 2.993 μm. Met.

(3) Molding test of thermoplastic resin When injection molding of a liquid crystal polymer was performed using the thermoplastic resin molding mold obtained as described above, an unsurface-treated thermoplastic resin molding mold (Comparative Example 1). Not only the rate of occurrence of gate residue was significantly reduced compared to (see), but also the gas contamination of the split mold was reduced.

1. 1. Surface treatment of runner part surface and parting surface of thermoplastic resin molding split mold The shape of the split mold is a disk shape of φ65 mm, the material is NAK55 (hardness: HRC42), and the pressure of compressed air in the special polishing treatment is 0. The order of shot peening treatment and blast treatment was changed with 3 MPa and the projection time of the particles set to 6 minutes. In the blast treatment, ceramic particles having a 50% average particle size (median diameter) of 50 μm were prepared with compressed air of 0.3 MPa. , A steel ball with a 50% average particle size (median diameter) of 100 μm is compressed by 0.4 MPa in a shot peening process by projecting on the surface of the runner site and the parting surface that have been specially polished at a projection angle of 90 ° for 1 minute. Thermoplastic as in Example 1 except that the surface of the runner site and the parting surface that had been blasted were projected with air at a projection angle of 90 ° for 1 minute, and the projection time of the particles in the special blast treatment was 6 minutes. The surface of the runner part and the parting surface of the resin molded split mold were surface-treated.

2. 2. Surface analysis of runner site surface and parting surface (1) Arithmetic mean roughness Ra measurement The arithmetic average roughness Ra of multiple sections of the runner site surface and parting surface described above was measured according to JIS B 0601-2001. The value was 0.342 μm.

(2) Measurement of maximum height Rz When the maximum height Rz of a plurality of sections of the runner site surface and the parting surface of the above-mentioned thermoplastic resin molded split mold was measured according to JIS B 0601-2001, the value was 3.651 μm. Met.

(3) Molding test of thermoplastic resin When injection molding of polyurethane was performed using the thermoplastic resin molding mold obtained as described above, an unsurface-treated thermoplastic resin molding mold (see Comparative Example 1). ), Not only the occurrence rate of short circuit was significantly reduced, but also the gas contamination of the split mold was reduced.

1. 1. Surface treatment of runner part surface and parting surface of thermoplastic resin molding split mold The material of the split mold is HPM-31 (hardness: HRC52), the order of shot peening treatment and blast treatment is changed, and 50% average in blast treatment. Ceramic particles with a particle size (median diameter) of 20 μm are projected onto the surface of the runner site and the parting surface that have been specially polished with compressed air of 0.4 MPa at a projection angle of 90 ° for 3 minutes, and 50 in the shot peening process. Example 1 except that a steel ball having a% average particle size (median diameter) of 100 μm was projected onto the surface of the blasted runner site and the parting surface with compressed air of 0.3 MPa at a projection angle of 90 ° for 3 minutes. The surface of the runner part and the parting surface of the thermoplastic resin molded split mold were surface-treated in the same manner as in the above.

2. 2. Surface analysis of runner site surface and parting surface (1) Arithmetic mean roughness Ra measurement The arithmetic average roughness Ra of multiple sections of the runner site surface and parting surface described above was measured according to JIS B 0601-2001. The value was 0.421 μm.

(2) Measurement of maximum height Rz When the maximum height Rz of a plurality of sections of the runner site surface and the parting surface of the above-mentioned thermoplastic resin molded split mold was measured according to JIS B 0601-2001, the value was 5.023 μm. Met.

(3) Molding test of thermoplastic resin When injection molding of polyvinyl chloride was performed using the thermoplastic resin molding mold obtained as described above, an unsurface-treated thermoplastic resin molding mold (Comparative Example). Not only was the incidence of burning significantly reduced compared to (see 1), but also the gas contamination of the split mold was reduced.

(Comparative Example 1)
The surface of the runner part and the parting surface of the thermoplastic resin molded split mold were not surface-treated, and the surface of the runner part and the parting surface was analyzed in the same manner as in Example 1. As a result, the arithmetic average roughness Ra of the runner portion surface and the parting surface of the thermoplastic resin molded split mold was 0.032 μm, and the maximum height Rz was 0.281 μm.

Further, when the spiral flow test was performed under the same conditions as in Example 1 without surface treatment on the groove surface of the mold in which the spiral groove was formed, the length of the resin molded product was 178 mm. The peak pressure was 29.0 MPa.

Further, injection molding of polyamide 6T, polybutylene terephthalate, polyphenylene sulfide, liquid crystal polymer, polyurethane, and polyvinyl chloride was performed using an untreated thermoplastic resin molding mold. The molding method and molding conditions for injection molding of polyamide 6T are the same as the molding method and molding conditions in Example 1, and the molding method and molding conditions for injection molding of polybutylene terephthalate are the same as those in Example 2. The same, the molding method and molding conditions in the injection molding of polyphenylene sulfide are the same as the molding method and molding conditions in Example 3, and the molding method and molding conditions in the injection molding of the liquid crystal polymer are the same as the molding method and molding conditions in Example 4. The same, the molding method and molding conditions in the injection molding of polyurethane are the same as the molding method and molding conditions in Example 5, and the molding method and molding conditions in injection molding of polyvinyl chloride are the same as the molding method and molding conditions in Example 6. It was made the same.

In the molding of the polyamide 6T, the occurrence rate of weld lines and burns was higher than that in the molding test of Example 1, and gas stains on the parting surface of the split mold were conspicuous. In the molding of polybutylene terephthalate, the generation rate of air bubbles was higher than that in the molding test of Example 2, and gas contamination on the parting surface of the split mold was conspicuous. In the molding of polyphenylene sulfide, the rate of occurrence of burrs was higher than that in the molding test of Example 3, and gas contamination on the parting surface of the split mold was conspicuous. In the molding of the liquid crystal polymer, the generation rate of gate residue was higher than that in the molding test of Example 4, and gas contamination on the parting surface of the split mold was conspicuous. In the polyurethane molding, the occurrence rate of short circuit was higher than that in the molding test of Example 5, and gas stains on the parting surface of the split mold were conspicuous. In the molding of polyvinyl chloride, the occurrence rate of burning was higher than that in the molding test of Example 6, and gas stains on the parting surface of the split mold were conspicuous.

(Comparative Example 2)
1. 1. Surface treatment of the runner part surface and parting surface of the thermoplastic resin molded split mold A steel ball with a 50% average particle size (median diameter) of 50 μm is used with 0.4 MPa of compressed air to form the runner part surface and parting surface of the split mold. The surface was projected at a projection angle of 90 ° for 2 minutes, and the same surface was set to 8-S surface roughness.

2. 2. Surface Analysis of Runner Site Surface and Parting Surface (1) Measurement of Arithmetic Mean Roughness Ra The arithmetic mean roughness Ra of a plurality of sections of the runner site surface and parting surface described above was measured according to JIS B 0601-2001. The value was 1.189 μm.

(2) Measurement of maximum height Rz When the maximum height Rz of a plurality of sections of the runner site surface and the parting surface of the above-mentioned thermoplastic resin molded split mold was measured according to JIS B 0601-2001, the value was 8.228 μm. Met.

(3) Spiral flow test The same surface treatment as described above was applied to the groove surface of the mold (width 130 mm × depth 130 mm) in which a spiral groove having a width of 3 mm and a depth of 4 mm was formed. Then, a spiral flow test was performed using the polyamide 6T under the same conditions as those shown in Example 1. The length of the spiral resin molded product formed in the groove for each thermoplastic resin was 183 mm, and the peak pressure was 29.0 MPa.

(4) Molding test of thermoplastic resin Polyamide 6T, polybutylene terephthalate, polyphenylene sulfide, liquid crystal polymer, polyurethane, and polyvinyl chloride were injection-molded using the above-mentioned thermoplastic resin molding mold. The molding method and molding conditions for injection molding of polyamide 6T are the same as the molding method and molding conditions in Example 1, and the molding method and molding conditions for injection molding of polybutylene terephthalate are the same as those in Example 2. The same, the molding method and molding conditions in the injection molding of polyphenylene sulfide are the same as the molding method and molding conditions in Example 3, and the molding method and molding conditions in the injection molding of the liquid crystal polymer are the same as the molding method and molding conditions in Example 4. The same, the molding method and molding conditions in injection molding of polyurethane are the same as the molding method and molding conditions in Example 5, and the molding method and molding conditions in injection molding of polyvinyl chloride are the same as the molding method and molding conditions in Example 6. It was made the same.

In the molding of the polyamide 6T, the occurrence rate of weld lines and burns was higher than that in the molding test of Example 1, and gas stains on the parting surface of the split mold were conspicuous. In the molding of polybutylene terephthalate, the generation rate of air bubbles was higher than that in the molding test of Example 2, and gas contamination on the parting surface of the split mold was conspicuous. In the molding of polyphenylene sulfide, the rate of occurrence of burrs was higher than that in the molding test of Example 3, and gas contamination on the parting surface of the split mold was conspicuous. In the molding of the liquid crystal polymer, the generation rate of gate residue was higher than that in the molding test of Example 4, and gas contamination on the parting surface of the split mold was conspicuous. In the polyurethane molding, the occurrence rate of short circuit was higher than that in the molding test of Example 5, and gas stains on the parting surface of the split mold were conspicuous. In the molding of polyvinyl chloride, the occurrence rate of burning was higher than that in the molding test of Example 6, and gas stains on the parting surface of the split mold were conspicuous.

The arithmetic mean roughness Ra and maximum height Rz measured in Example 1, Comparative Example 1 and Comparative Example 2 and the results of the spiral flow test are summarized in the following reference table. From the following results, it is clear that the mold according to Example 1 can not only have a longer flow length than the mold according to Comparative Example 1 and Comparative Example 2, but also can reduce the peak pressure. rice field.

(Reference table)

The present invention relates to a thermoplastic resin molded member, particularly a thermoplastic resin molded member having a resin flow path portion. The present invention also relates to a method for surface processing a thermoplastic resin molded member. Furthermore, the present invention relates to a thermoplastic resin molded mold. The present invention also relates to a method for processing a parting surface of a thermoplastic resin molded split mold.

In the past, it has been proposed to "form a wall surface in contact with a resin in a runner of a resin-sealed mold in a rough surface shape" (see, for example, Japanese Patent Application Laid-Open No. 62-140426). By forming the wall surface of the runner in a rough surface shape in this way, the temperature distribution of the transfer resin can be made uniform, and the transfer of the resin to the cavity can be facilitated as well as the cavity. The inflow of air bubbles into the plastic can be reduced.

Japanese Unexamined Patent Publication No. 62-140426

By the way, it cannot be said that the generation of defective products due to the generation of weld lines, bubbles (voids), shorts, burrs, burning, and gate residue has been sufficiently reduced in the field of thermoplastic resin molding.

An object of the present invention is to provide a thermoplastic resin molded member capable of reducing the occurrence rate of defective products.

The thermoplastic resin molding member according to the first aspect of the present invention is, for example, a member such as a mold or an injection member, and the surface of at least the thermoplastic resin flow path portion (excluding the cavity portion) is 0.1 μm or more. The arithmetic average roughness Ra in the range of 0.5 μm or less is shown, and the maximum height Rz in the range of 0.5 μm or more and 5.5 μm or less is shown. It is preferable that the surface of the thermoplastic resin flow path portion shows an arithmetic average roughness Ra in the range of 0.15 μm or more and 0.45 μm or less. Further, the surface of the thermoplastic resin flow path portion preferably shows a maximum height Rz in the range of 1.0 μm or more and 5.5 μm or less, and a maximum height Rz in the range of 1.5 μm or more and 5.5 μm or less. It is more preferable to show.

As a result of diligent studies by the inventor of the present application, when a thermoplastic resin is molded using a thermoplastic resin molding member having the above-mentioned roughness on the surface of the thermoplastic resin flow path portion, weld lines, bubbles (voids), shorts, etc. It has been clarified that the generation of burrs, burning, gate residue, etc. is suppressed, and as a result, the generation rate of defective products can be reduced and the life of the thermoplastic resin molded member can be extended.

The method according to the second aspect of the present invention is a method of applying surface treatment, in which the surface of the thermoplastic resin flow path portion (excluding the cavity portion) of the thermoplastic resin molding member is 0.1 μm or more. The surface of the thermoplastic resin flow path portion of the thermoplastic resin molding member shows the arithmetic average roughness Ra in the range of 0.5 μm or less and the maximum height Rz in the range of 0.5 μm or more and 5.5 μm or less. It will be processed. It is preferable that the surface of the thermoplastic resin flow path portion shows an arithmetic average roughness Ra in the range of 0.15 μm or more and 0.45 μm or less. Further, the surface of the thermoplastic resin flow path portion preferably shows a maximum height Rz in the range of 1.0 μm or more and 5.5 μm or less, and a maximum height Rz in the range of 1.5 μm or more and 5.5 μm or less. It is more preferable to show.

As a result of diligent studies by the inventor of the present application, when a thermoplastic resin is molded using the thermoplastic resin molding member having the above-mentioned surface processing applied to the thermoplastic resin flow path portion, weld lines, bubbles (voids), shorts, and burrs are found. It has been clarified that the generation, burning, generation of gate residue, etc. are suppressed, and as a result, the generation rate of defective products can be reduced and the life of the thermoplastic resin molded member can be extended.

The method according to the third aspect of the present invention is the method according to the second aspect, and the surface treatment is performed by at least one of a shot peening treatment and a blast treatment.

Therefore, in this method, the surface processing can be performed by appropriately adjusting the specific gravity, particle size, hardness, collision speed, collision angle, etc. of the shot or the abrasive.

The method according to the fourth aspect of the present invention is the method according to the second aspect, and the surface treatment is performed by a polishing treatment and at least one of a shot peening treatment and a blast treatment carried out thereafter.

Here, the polishing process is performed before at least one of the shot peening process and the blast process is performed. Therefore, in this method, when the surface condition of the thermoplastic resin flow path portion of the thermoplastic resin molding member to be processed is not good, at least one of the shot peening treatment and the blast treatment is performed after the surface condition is improved by polishing treatment. Can be processed.

The thermoplastic resin molded split mold according to the fifth aspect of the present invention shows, for example, an arithmetic mean roughness Ra in the range of at least 0.1 μm or more and 0.5 μm or less on the parting surface, and 0.5 μm or more and 5.5 μm. The maximum height Rz within the following range is shown. The parting surface preferably shows an arithmetic mean roughness Ra in the range of 0.15 μm or more and 0.45 μm or less. Further, the parting surface preferably shows a maximum height Rz in the range of 1.0 μm or more and 5.5 μm or less, and more preferably shows a maximum height Rz in the range of 1.5 μm or more and 5.5 μm or less. ..

By the way, when a thermoplastic resin is molded using a split mold, gas stains often adhere to the parting surface. Then, if the gas stains are accumulated, the shape of the cavity may gradually change, which is not preferable. Therefore, as a result of diligent studies by the inventor of the present application, when the thermoplastic resin is molded by using the thermoplastic resin molding mold having the above-mentioned roughness of the parting surface, the gas discharge property is improved, and as a result, the gas is discharged. It became clear that dirt can be reduced.

The method according to the sixth aspect of the present invention is a method of applying surface processing, in which the arithmetic average coarseness of the parting surface of the thermoplastic resin molded split mold is within the range of 0.1 μm or more and 0.5 μm or less. The parting surface of the thermoplastic resin molded split mold is machined so as to show Ra and a maximum height Rz within the range of 0.5 μm or more and 5.5 μm or less. The parting surface preferably shows an arithmetic average roughness Ra in the range of 0.15 μm or more and 0.45 μm or less. Further, the parting surface preferably shows a maximum height Rz in the range of 1.0 μm or more and 5.5 μm or less, and more preferably shows a maximum height Rz in the range of 1.5 μm or more and 5.5 μm or less. ..

As a result of diligent studies by the inventor of the present application, when the thermoplastic resin is molded by using the thermoplastic resin molding mold having the above-mentioned roughness of the parting surface, the gas discharge property is improved, and as a result, gas stains are removed. It became clear that it can be reduced.

The method according to the seventh aspect of the present invention is the method according to the sixth aspect, and the processing of the parting surface is performed by at least one of a shot peening process and a blast process.

Therefore, in this method, the surface of the parting surface can be processed by appropriately adjusting the specific gravity, particle size, hardness, collision speed, collision angle, etc. of the shot or the abrasive.

The method according to the eighth aspect of the present invention is the method according to the sixth aspect, and the processing of the parting surface is performed by a polishing treatment and at least one of a shot peening treatment and a blasting treatment carried out thereafter. To.

Here, the polishing process is performed before at least one of the shot peening process and the blast process is performed. Therefore, in this method, when the condition of the parting surface of the thermoplastic resin molded split mold to be processed is not good, at least one of the shot peening treatment and the blast treatment is performed after the condition of the parting surface is improved by polishing treatment. Can be processed.

-First Embodiment-
The thermoplastic resin molding member according to the first embodiment of the present invention is, for example, a member such as a mold or an injection member, and the surface of at least the surface of the thermoplastic resin flow path portion is in the range of 0.1 μm or more and 0.5 μm or less. The arithmetic mean roughness Ra in the range is shown, and the maximum height Rz in the range of 0.5 μm or more and 5.5 μm or less is shown. The arithmetic average roughness Ra of the surface of the thermoplastic resin flow path portion is preferably in the range of 0.15 μm or more and 0.45 μm or less. Further, the maximum height Rz of the surface of the thermoplastic resin flow path portion is preferably in the range of 1.0 μm or more and 5.5 μm or less, and more preferably in the range of 1.5 μm or more and 5.5 μm or less. .. Further, here, the thermoplastic resin flow path portion is a portion through which the thermoplastic resin melted by heat flows, and is, for example, a sprue bush portion, a runner portion, a gate portion, or the like. Further, the thermoplastic resin referred to here is, for example, polyamide, polycarbonate, polybutylene terephthalate, polyethylene terephthalate, syndiotactic polystyrene, polyphenylene sulfide, liquid crystal polymer, polymethyl methacrylate, polyacrylic acid ester, polyvinyl chloride, polystyrene. , Polycarbonate, polyethylene, polypropylene, ABS resin, fluororesin and the like.

By the way, the thermoplastic resin molded member according to the first embodiment of the present invention is manufactured through a roughening step. If necessary, the pretreatment step may be carried out before the roughening step, or the post-treatment step (for example, a surface smoothing step or the like) may be carried out after the roughening step. Hereinafter, these steps will be described in detail.

(1) Roughening Step In the roughening step, for example, at least one of a shot peening treatment and a blast treatment is carried out on the thermoplastic resin flow path portion of the thermoplastic resin molding member.

In the shot peening treatment, spherical particles corresponding to the finished surface roughness are collided with compressed air at high speed on the thermoplastic resin flow path portion, and circular pore-shaped or protruding unevenness is formed on the surface thereof. Here, the spherical particles are preferably steel balls. Further, the diameter of the spherical particles and the pressure of the compressed air are set so that, for example, the arithmetic mean roughness Ra of the finished surface is within the range of 0.1 μm or more and 0.3 μm or less, and the maximum height Rz is 1.0 μm or more. When it is within the range of 5 μm or less, it is preferably within the range of 50 μm or more and 100 μm or less and 0.2 MPa, and the arithmetic mean roughness Ra of the finished surface is within the range of 0.2 μm or more and 0.4 μm or less and the maximum. When the height Rz is within the range of 1.5 μm or more and 3.0 μm or less, it is preferably within the range of 50 μm or more and 100 μm or less and 0.3 MPa, and the arithmetic mean roughness Ra of the finished surface is 0.3 μm or more and 0. When the maximum height Rz is within the range of 2.5 μm or less and the maximum height Rz is within the range of 2.0 μm or more and 3.5 μm or less, it is preferably within the range of 100 μm or more and 150 μm or less and 0.2 MPa. When the average roughness Ra is within the range of 0.4 μm or more and 0.5 μm or less and the maximum height Rz is within the range of 2.5 μm or more and 4.0 μm or less, the range is 100 μm or more and 150 μm or less and 0.3 MPa. Is preferable. Further, the projection angle of the spherical particles is preferably in the range of 60 ° or more and 90 ° or less with respect to the surface of the thermoplastic resin flow path portion, and the treatment time is preferably in the range of 15 minutes or more and 30 minutes or less. preferable.

In the blast treatment, polygonal particles or spherical particles depending on the roughness of the finished surface are collided with compressed air at high speed on the thermoplastic resin flow path portion, and circular pore-like or protrusion-like irregularities are formed on the surface. .. Here, the particles are preferably ceramic particles. The diameter of the spherical particles and the pressure of the compressed air are such that the arithmetic mean roughness Ra of the finished surface is within the range of 0.1 μm or more and 0.3 μm or less, and the maximum height Rz is 1.0 μm or more and 2.5 μm or less. When it is within the range of, it is preferably within the range of 20 μm or more and 50 μm or less and 0.4 MPa, and the arithmetic mean roughness Ra of the finished surface is within the range of 0.2 μm or more and 0.4 μm or less and the maximum height. When Rz is in the range of 1.5 μm or more and 3.0 μm or less, it is preferably in the range of 20 μm or more and 50 μm or less and 0.4 MPa, and the arithmetic mean roughness Ra of the finished surface is 0.3 μm or more and 0.5 μm. When the maximum height Rz is within the range of 2.0 μm or more and 3.5 μm or less, it is preferably within the range of 20 μm or more and 50 μm or less and 0.3 MPa, and the arithmetic mean roughness of the finished surface is preferable. When Ra is in the range of 0.4 μm or more and 0.5 μm or less and the maximum height Rz is in the range of 2.5 μm or more and 4.0 μm or less, it is set in the range of 20 μm or more and 50 μm or less and 0.3 MPa. Is preferable. Further, the projection angle of the particles is preferably in the range of 60 ° or more and 90 ° or less with respect to the surface of the thermoplastic resin flow path portion, and the treatment time is preferably in the range of 15 minutes or more and 30 minutes or less. ..

(2) Pretreatment Step The pretreatment step is preferably performed when the arithmetic mean roughness Ra of the surface of the thermoplastic resin flow path portion of the thermoplastic resin molding member is 1.0 μm or more. This is to obtain a surface having a desired roughness in the roughening step of the subsequent step. Examples of the pretreatment include a polishing treatment such as special polishing. In the special polishing process, particles in which fine abrasive grains are laminated on an elastic core material such as resin or rubber are slid by compressed air or centrifugal force in the thermoplastic resin flow path portion, and are formed by cutting or polishing. Unevenness marks are removed and surface roughness is reduced. Here, the particles are preferably particles in which a resin core is coated with abrasive grains. The diameter of the core is preferably in the range of 0.1 mm or more and 0.8 mm or less, the diameter of the abrasive grains is preferably in the range of 1 μm or more and 8 μm or less, and the pressure of the compressed air is 0.2 MPa. It is preferably in the range of 0.5 MPa or less. Further, the projection angle of the particles is preferably in the range of 45 ° or more and 60 ° or less with respect to the surface of the thermoplastic resin flow path portion, and the treatment time is preferably in the range of 30 minutes or more and 45 minutes or less. ..

(3) Post-treatment step The post-treatment step is a step for adjusting the surface having a desired roughness at a fine level, and is performed for the purpose of polishing convex portions or removing roughness, for example. Examples of the post-processing include special blast processing and the like. In the special blast treatment, particles coated with fine abrasive grains on an elastic core material are slid on the thermoplastic resin flow path by compressed air or centrifugal force, and uneven marks formed by cutting or polishing are removed. Surface roughness is reduced. Here, it is preferable that the particles are rubber or resin cores coated with abrasive grains. Further, the diameter of the core is preferably in the range of 0.1 mm or more and 1.0 mm or less, and the diameter of the abrasive grains is preferably in the range of 1 μm or more and 5 μm or less. Further, when the particles are sprayed with compressed air, the pressure of the compressed air is preferably 0.3 MPa. Further, the projection angle of the particles is preferably in the range of 45 ° or more and 60 ° or less with respect to the surface of the thermoplastic resin flow path portion, and the treatment time is preferably in the range of 30 minutes or more and 45 minutes or less. ..

<Characteristics of the thermoplastic resin molded member according to the first embodiment of the present invention>
When the thermoplastic resin is molded by the thermoplastic resin molding member according to the first embodiment of the present invention, the generation of weld lines, bubbles (voids), shorts, burrs, burning, gate residue, etc. is suppressed, and as a result, the generation is suppressed. The rate of defective products can be reduced.

-Second Embodiment-
The thermoplastic resin molded mold according to the second embodiment shows an arithmetic mean roughness Ra in the range of at least 0.1 μm or more and 0.5 μm or less on the parting surface, and is in the range of 0.5 μm or more and 5.5 μm or less. Indicates the maximum height Rz of. The arithmetic average roughness Ra of the parting surface is preferably in the range of 0.15 μm or more and 0.45 μm or less. Further, the maximum height Rz of the parting surface is preferably in the range of 1.0 μm or more and 5.5 μm or less, and more preferably in the range of 1.5 μm or more and 5.5 μm or less.

By the way, the thermoplastic resin molded split mold according to the second embodiment of the present invention is manufactured through a roughening step. If necessary, the pretreatment step may be carried out before the roughening step, or the post-treatment step (for example, a surface smoothing step or the like) may be carried out after the roughening step. The roughening step, the pretreatment step, and the posttreatment step are the same as the roughening step, the pretreatment step, and the posttreatment step according to the first embodiment, except that the surface treatment target is the parting surface. Therefore, the description thereof will be omitted.

<Characteristics of the thermoplastic resin molded split mold according to the second embodiment of the present invention>
When the thermoplastic resin is molded by the thermoplastic resin molding mold according to the second embodiment of the present invention, the gas discharge property is improved, and as a result, gas contamination can be reduced.

Hereinafter, Examples and Comparative Examples will be shown to explain the present invention in more detail, but the present invention is not limited to this Example.

1. 1. Surface treatment of the runner part surface and parting surface of the thermoplastic resin molded split mold Special polishing treatment, shot peening treatment, blasting treatment and special blasting treatment are applied to the runner part surface and parting surface of the thermoplastic resin molded split mold. By applying in this order, the surface structure of the runner portion of the desired thermoplastic resin molded split mold was obtained.

The special polishing treatment was carried out as a pretreatment. In the special polishing process, particles coated with a resin core material having a 50% average particle size (median diameter) of 0.5 mm and abrasive grains having a 50% average particle size (median diameter) of 2 μm are coated with 0.4 MPa compressed air. , The surface of the runner portion and the parting surface of the thermoplastic resin molded split mold (dimensions: depth 250 mm × width 150 mm, material: SKD11, hardness: HRC58) were projected at a projection angle of 45 ° for 10 minutes.

In the shot peening treatment, a steel ball having a 50% average particle size (median diameter) of 50 μm is subjected to specially polished runner site surface and parting surface with compressed air of 0.4 MPa at a projection angle of 90 ° for 2 minutes. Projected.

In the blasting process, ceramic particles with a 50% average particle size (median diameter) of 50 μm are projected with 0.4 MPa compressed air onto the surface of the runner site and the parting surface that have been shot peened at a projection angle of 90 ° for 2 minutes. bottom.

The special blast treatment was performed as a post-treatment. In the special blast treatment, particles coated with abrasive grains having a 50% average particle size (median diameter) of 2 μm on a resin core material having a 50% average particle size (median diameter) of 0.5 mm are coated with compressed air of 0.2 MPa. , The surface of the runner site and the parting surface that had been blasted were projected at a projection angle of 45 ° for 10 minutes.

2. 2. Surface analysis of runner site surface and parting surface (1) Arithmetic mean roughness Ra measurement The arithmetic average roughness Ra of multiple sections of the runner site surface and parting surface described above was measured according to JIS B 0601-2001. The value was 0.180 μm.

(2) Measurement of maximum height Rz When the maximum height Rz of a plurality of sections of the runner site surface and the parting surface of the above-mentioned thermoplastic resin molded split mold was measured according to JIS B 0601-2001, the value was 1.621 μm. Met.

(3) Spiral flow test The same surface treatment as described above was applied to the groove surface of the mold (width 130 mm × depth 130 mm) in which a spiral groove having a width of 3 mm and a depth of 4 mm was formed. Then, under the conditions shown below, polyamide 6T (nylon 66) was injected from the injection molding machine into the groove of the mold through the center hole of the mold for 2 seconds, then cooled for 4 seconds, and formed in the groove. When the length of the spiral resin molded product was measured, the length was 203 mm and the peak pressure was 18.2 MPa. During this test, the temperature of the mold was kept at 80 ° C.

-Mold temperature: 80 ° C
-Resin temperature: 270 ° C
・ Filling speed: 100 mm / sec ・ Injection time: 2 seconds ・ Cooling time: 4 seconds ・ Weighing: 15.00 mm
・ Holding pressure: 0.3MPa
・ Limit speed: 10.0 mm / sec ・ Limit pressure: 5.0 MPa
・ Decompression speed: 10.0mm / sec ・ Decompression position: 3.00mm
・ Screw rotation slow speed: 0%
・ Screw rotation throw distance: 0.00mm
・ Screw back pressure: 10.0 MPa
・ Screw rotation speed: 80%

(4) Molding test of thermoplastic resin When injection molding of polyamide 6T was performed using the thermoplastic resin molding mold obtained as described above, an unsurface-treated thermoplastic resin molding mold (Comparative Example 1). Not only was the incidence of weld lines and burns reduced compared to (see), but also split-mold gas contamination was reduced.

1. 1. Surface treatment of runner part surface and parting surface of thermoplastic resin molding split mold The dimensions of the split mold are 150 mm in depth x 150 mm in width, the projection time of particles in special polishing treatment is 8 minutes, and the pressure of compressed air in shot peening treatment. The projection time of the steel ball is 1.5 minutes, the projection time of the ceramic particles in the blast treatment is 1.5 minutes, the pressure of the compressed air in the special blast treatment is 0.3 MPa, and the particles. The surface of the runner portion and the parting surface of the thermoplastic resin molded split mold were surface-treated in the same manner as in Example 1 except that the projection time was set to 6 minutes.

2. 2. Surface analysis of runner site surface and parting surface (1) Arithmetic mean roughness Ra measurement The arithmetic average roughness Ra of multiple sections of the runner site surface and parting surface described above was measured according to JIS B 0601-2001. The value was 0.238 μm.

(2) Measurement of maximum height Rz When the maximum height Rz of a plurality of sections of the runner site surface and the parting surface of the above-mentioned thermoplastic resin molded split mold was measured according to JIS B 0601-2001, the value was 2.183 μm. Met.

(3) Molding test of thermoplastic resin When injection molding of polybutylene terephthalate was performed using the thermoplastic resin molding mold obtained as described above, an unsurface-treated thermoplastic resin molding mold (Comparative Example). Not only the generation rate of bubbles was reduced as compared with 1), but also the gas contamination of the split mold was reduced.

1. 1. Surface treatment of runner part surface and parting surface of thermoplastic resin molding split mold The dimensions of the split mold are 200 mm in depth x 150 mm in width, and the material is HPM-31 (hardness: HRC58), and the projection time of particles in the special polishing treatment. The order of shot peening treatment and blast treatment was changed to 15 minutes, and in the blast treatment, ceramic particles having a 50% average particle size (median diameter) of 20 μm were treated with compressed air of 0.4 MPa and specially polished runner parts. A runner that has been blasted with compressed air of 0.2 MPa on a steel ball with a 50% average particle size (median diameter) of 100 μm in a shot peening process by projecting onto the surface and parting surface at a projection angle of 90 ° for 3 minutes. Same as Example 1 except that the surface of the site and the parting surface are projected at a projection angle of 90 ° for 3 minutes, the pressure of the compressed air in the special blast treatment is 0.3 MPa, and the projection time of the particles is 15 minutes. The surface of the runner part and the parting surface of the thermoplastic resin molded split mold were surface-treated.

2. 2. Surface analysis of runner site surface and parting surface (1) Arithmetic mean roughness Ra measurement The arithmetic average roughness Ra of multiple sections of the runner site surface and parting surface described above was measured according to JIS B 0601-2001. The value was 0.291 μm.

(2) Measurement of maximum height Rz When the maximum height Rz of a plurality of sections of the runner site surface and the parting surface of the above-mentioned thermoplastic resin molded split mold was measured according to JIS B 0601-2001, the value was 2.993 μm. Met.

(3) Molding test of thermoplastic resin When injection molding of polyphenylene sulfide was performed using the thermoplastic resin molding mold obtained as described above, an unsurface-treated thermoplastic resin molding mold (Comparative Example 1). Not only the rate of burr generation was reduced compared to (see), but also the gas contamination of the split mold was significantly reduced.

1. 1. Surface treatment of runner part surface and parting surface of thermoplastic resin molding split mold The dimensions of the split mold are 50 mm in depth x 20 mm in width, the material is STAVAX (hardness: HRC52), and the projection time of particles in the special polishing treatment is 5. The order of shot peening treatment and blast treatment was changed, and in the blast treatment, ceramic particles with a 50% average particle size (median diameter) of 20 μm were treated with 0.4 MPa of compressed air to the surface of the runner site and the specially polished runner site. A steel ball with a 50% average particle size (median diameter) of 50 μm is projected onto the parting surface at a projection angle of 90 ° for 1 minute, and the surface of the runner site that has been blasted with 0.2 MPa of compressed air. And the surface of the runner site and the party of the thermoplastic resin molded split mold as in Example 1 except that the projection was performed on the parting surface at a projection angle of 90 ° for 1 minute and the projection time of the particles in the special blasting treatment was 3 minutes. The surface of the polishing surface was treated.

2. 2. Surface analysis of runner site surface and parting surface (1) Arithmetic mean roughness Ra measurement The arithmetic average roughness Ra of multiple sections of the runner site surface and parting surface described above was measured according to JIS B 0601-2001. The value was 0.291 μm.

(2) Measurement of maximum height Rz When the maximum height Rz of a plurality of sections of the runner site surface and the parting surface of the above-mentioned thermoplastic resin molded split mold was measured according to JIS B 0601-2001, the value was 2.993 μm. Met.

(3) Molding test of thermoplastic resin When injection molding of a liquid crystal polymer was performed using the thermoplastic resin molding mold obtained as described above, an unsurface-treated thermoplastic resin molding mold (Comparative Example 1). Not only the rate of occurrence of gate residue was significantly reduced compared to (see), but also the gas contamination of the split mold was reduced.

1. 1. Surface treatment of runner part surface and parting surface of thermoplastic resin molding split mold The shape of the split mold is a disk shape of φ65 mm, the material is NAK55 (hardness: HRC42), and the pressure of compressed air in the special polishing treatment is 0. The order of shot peening treatment and blast treatment was changed with 3 MPa and the projection time of the particles set to 6 minutes. In the blast treatment, ceramic particles having a 50% average particle size (median diameter) of 50 μm were prepared with compressed air of 0.3 MPa. , A steel ball with a 50% average particle size (median diameter) of 100 μm is compressed by 0.4 MPa in a shot peening process by projecting on the surface of the runner site and the parting surface that have been specially polished at a projection angle of 90 ° for 1 minute. Thermoplastic as in Example 1 except that the surface of the runner site and the parting surface that had been blasted were projected with air at a projection angle of 90 ° for 1 minute, and the projection time of the particles in the special blast treatment was 6 minutes. The surface of the runner part and the parting surface of the resin molded split mold were surface-treated.

2. 2. Surface analysis of runner site surface and parting surface (1) Arithmetic mean roughness Ra measurement The arithmetic average roughness Ra of multiple sections of the runner site surface and parting surface described above was measured according to JIS B 0601-2001. The value was 0.342 μm.

(2) Measurement of maximum height Rz When the maximum height Rz of a plurality of sections of the runner site surface and the parting surface of the above-mentioned thermoplastic resin molded split mold was measured according to JIS B 0601-2001, the value was 3.651 μm. Met.

(3) Molding test of thermoplastic resin When injection molding of polyurethane was performed using the thermoplastic resin molding mold obtained as described above, an unsurface-treated thermoplastic resin molding mold (see Comparative Example 1). ), Not only the occurrence rate of short circuit was significantly reduced, but also the gas contamination of the split mold was reduced.

1. 1. Surface treatment of runner part surface and parting surface of thermoplastic resin molding split mold The material of the split mold is HPM-31 (hardness: HRC52), the order of shot peening treatment and blast treatment is changed, and 50% average in blast treatment. Ceramic particles with a particle size (median diameter) of 20 μm are projected onto the surface of the runner site and the parting surface that have been specially polished with compressed air of 0.4 MPa at a projection angle of 90 ° for 3 minutes, and 50 in the shot peening process. Example 1 except that a steel ball having a% average particle size (median diameter) of 100 μm was projected onto the surface of the blasted runner site and the parting surface with compressed air of 0.3 MPa at a projection angle of 90 ° for 3 minutes. The surface of the runner part and the parting surface of the thermoplastic resin molded split mold were surface-treated in the same manner as in the above.

2. 2. Surface analysis of runner site surface and parting surface (1) Arithmetic mean roughness Ra measurement The arithmetic average roughness Ra of multiple sections of the runner site surface and parting surface described above was measured according to JIS B 0601-2001. The value was 0.421 μm.

(2) Measurement of maximum height Rz When the maximum height Rz of a plurality of sections of the runner site surface and the parting surface of the above-mentioned thermoplastic resin molded split mold was measured according to JIS B 0601-2001, the value was 5.023 μm. Met.

(3) Molding test of thermoplastic resin When injection molding of polyvinyl chloride was performed using the thermoplastic resin molding mold obtained as described above, an unsurface-treated thermoplastic resin molding mold (Comparative Example). Not only was the incidence of burning significantly reduced compared to (see 1), but also the gas contamination of the split mold was reduced.

(Comparative Example 1)
The surface of the runner part and the parting surface of the thermoplastic resin molded split mold were not surface-treated, and the surface of the runner part and the parting surface was analyzed in the same manner as in Example 1. As a result, the arithmetic average roughness Ra of the runner portion surface and the parting surface of the thermoplastic resin molded split mold was 0.032 μm, and the maximum height Rz was 0.281 μm.

Further, when the spiral flow test was performed under the same conditions as in Example 1 without surface treatment on the groove surface of the mold in which the spiral groove was formed, the length of the resin molded product was 178 mm. The peak pressure was 29.0 MPa.

Further, injection molding of polyamide 6T, polybutylene terephthalate, polyphenylene sulfide, liquid crystal polymer, polyurethane, and polyvinyl chloride was performed using an untreated thermoplastic resin molding mold. The molding method and molding conditions for injection molding of polyamide 6T are the same as the molding method and molding conditions in Example 1, and the molding method and molding conditions for injection molding of polybutylene terephthalate are the same as those in Example 2. The same, the molding method and molding conditions in the injection molding of polyphenylene sulfide are the same as the molding method and molding conditions in Example 3, and the molding method and molding conditions in the injection molding of the liquid crystal polymer are the same as the molding method and molding conditions in Example 4. The same, the molding method and molding conditions in the injection molding of polyurethane are the same as the molding method and molding conditions in Example 5, and the molding method and molding conditions in injection molding of polyvinyl chloride are the same as the molding method and molding conditions in Example 6. It was made the same.

In the molding of the polyamide 6T, the occurrence rate of weld lines and burns was higher than that in the molding test of Example 1, and gas stains on the parting surface of the split mold were conspicuous. In the molding of polybutylene terephthalate, the generation rate of air bubbles was higher than that in the molding test of Example 2, and gas contamination on the parting surface of the split mold was conspicuous. In the molding of polyphenylene sulfide, the rate of occurrence of burrs was higher than that in the molding test of Example 3, and gas contamination on the parting surface of the split mold was conspicuous. In the molding of the liquid crystal polymer, the generation rate of gate residue was higher than that in the molding test of Example 4, and gas contamination on the parting surface of the split mold was conspicuous. In the polyurethane molding, the occurrence rate of short circuit was higher than that in the molding test of Example 5, and gas stains on the parting surface of the split mold were conspicuous. In the molding of polyvinyl chloride, the occurrence rate of burning was higher than that in the molding test of Example 6, and gas stains on the parting surface of the split mold were conspicuous.

(Comparative Example 2)
1. 1. Surface treatment of the runner part surface and parting surface of the thermoplastic resin molded split mold A steel ball with a 50% average particle size (median diameter) of 50 μm is used with 0.4 MPa of compressed air to form the runner part surface and parting surface of the split mold. The surface was projected at a projection angle of 90 ° for 2 minutes, and the same surface was set to 8-S surface roughness.

2. 2. Surface Analysis of Runner Site Surface and Parting Surface (1) Measurement of Arithmetic Mean Roughness Ra The arithmetic mean roughness Ra of a plurality of sections of the runner site surface and parting surface described above was measured according to JIS B 0601-2001. The value was 1.189 μm.

(2) Measurement of maximum height Rz When the maximum height Rz of a plurality of sections of the runner site surface and the parting surface of the above-mentioned thermoplastic resin molded split mold was measured according to JIS B 0601-2001, the value was 8.228 μm. Met.

(3) Spiral flow test The same surface treatment as described above was applied to the groove surface of the mold (width 130 mm × depth 130 mm) in which a spiral groove having a width of 3 mm and a depth of 4 mm was formed. Then, a spiral flow test was performed using the polyamide 6T under the same conditions as those shown in Example 1. The length of the spiral resin molded product formed in the groove for each thermoplastic resin was 183 mm, and the peak pressure was 29.0 MPa.

(4) Molding test of thermoplastic resin Polyamide 6T, polybutylene terephthalate, polyphenylene sulfide, liquid crystal polymer, polyurethane, and polyvinyl chloride were injection-molded using the above-mentioned thermoplastic resin molding mold. The molding method and molding conditions for injection molding of polyamide 6T are the same as the molding method and molding conditions in Example 1, and the molding method and molding conditions for injection molding of polybutylene terephthalate are the same as those in Example 2. The same, the molding method and molding conditions in the injection molding of polyphenylene sulfide are the same as the molding method and molding conditions in Example 3, and the molding method and molding conditions in the injection molding of the liquid crystal polymer are the same as the molding method and molding conditions in Example 4. The same, the molding method and molding conditions in injection molding of polyurethane are the same as the molding method and molding conditions in Example 5, and the molding method and molding conditions in injection molding of polyvinyl chloride are the same as the molding method and molding conditions in Example 6. It was made the same.

In the molding of the polyamide 6T, the occurrence rate of weld lines and burns was higher than that in the molding test of Example 1, and gas stains on the parting surface of the split mold were conspicuous. In the molding of polybutylene terephthalate, the generation rate of air bubbles was higher than that in the molding test of Example 2, and gas contamination on the parting surface of the split mold was conspicuous. In the molding of polyphenylene sulfide, the rate of occurrence of burrs was higher than that in the molding test of Example 3, and gas contamination on the parting surface of the split mold was conspicuous. In the molding of the liquid crystal polymer, the generation rate of gate residue was higher than that in the molding test of Example 4, and gas contamination on the parting surface of the split mold was conspicuous. In the polyurethane molding, the occurrence rate of short circuit was higher than that in the molding test of Example 5, and gas stains on the parting surface of the split mold were conspicuous. In the molding of polyvinyl chloride, the occurrence rate of burning was higher than that in the molding test of Example 6, and gas stains on the parting surface of the split mold were conspicuous.

The arithmetic mean roughness Ra and maximum height Rz measured in Example 1, Comparative Example 1 and Comparative Example 2 and the results of the spiral flow test are summarized in the following reference table. From the following results, it is clear that the mold according to Example 1 can not only have a longer flow length than the mold according to Comparative Example 1 and Comparative Example 2, but also can reduce the peak pressure. rice field.

(Reference table)

Claims (8)

At least the surface of the thermoplastic resin flow path shows an arithmetic mean roughness Ra in the range of 0.1 μm or more and 0.5 μm or less, and a maximum height Rz in the range of 0.5 μm or more and 5.5 μm or less. Resin molding member. Arithmetic average roughness Ra within the range of 0.1 μm or more and 0.5 μm or less and maximum height Rz within the range of 0.5 μm or more and 5.5 μm or less on the surface of the thermoplastic resin flow path portion of the thermoplastic resin molded member. As shown, a method of processing the surface. The method according to claim 2, wherein the surface processing is performed by at least one of a shot peening treatment and a blasting treatment. The method according to claim 2, wherein the surface processing is performed by a polishing treatment and at least one of a shot peening treatment and a blasting treatment performed thereafter. A thermoplastic resin molded mold having a parting surface showing an arithmetic mean roughness Ra in the range of 0.1 μm or more and 0.5 μm or less and a maximum height Rz in the range of 0.5 μm or more and 5.5 μm or less. As shown by the arithmetic average roughness Ra in the range of 0.1 μm or more and 0.5 μm or less and the maximum height Rz in the range of 0.5 μm or more and 5.5 μm or less, the parting surface of the thermoplastic resin molded split mold is shown. A method for processing the parting surface. The method according to claim 6, wherein the processing of the parting surface is performed by at least one of a shot peening process and a blast process. The method according to claim 6, wherein the processing of the parting surface is performed by a polishing treatment and at least one of a shot peening treatment and a blasting treatment performed thereafter.