WO2006038617A1

WO2006038617A1 - Metal mold for hollow molding

Info

Publication number: WO2006038617A1
Application number: PCT/JP2005/018352
Authority: WO
Inventors: Yasuhiro Suzuki
Original assignee: Suzuka Fuji Xerox Co., Ltd.
Priority date: 2004-10-07
Filing date: 2005-10-04
Publication date: 2006-04-13

Abstract

[PROBLEMS] Generally, hollow molded articles produced through gas injection in a molten resin are provided with a rib as a gas flow channel. However, this rib poses such a problem that the hollow molded articles at surfaces suffer appearance deteriorations, such as sink, transfer spots and whitening at hollow formation. [MEANS FOR SOLVING PROBLEMS] There is provided a metal mold for production of a molded article with hollow, which metal mold on its cavity surface from the position of injection of pressurized fluid in the cavity or the vicinity of the injection position to the region for forming of the hollow of the molded article or the vicinity of the forming region is furnished with linear surface treatment with a material of thermal conductance different from that of the material of the metal mold so as to cause the surface treatment to fulfill the function as a gas channel.

Description

Specification

Die for hollow molding

Technical field

The present invention relates to a hollow molding die for producing a hollow molded product by injecting (pressing) a pressurized fluid into a molten resin injected into a mold cavity and cooling it. Background art

[0002] It is known that gas assist molding, which is a kind of hollow molding method, can produce a hollow molded article without shrinkage or warpage (see, for example, Patent Document 1).

In this gas assist molding, as a passage (hereinafter referred to as “gas channel”) for injecting a pressurized fluid into a molded product, a fluid injection part to the molded product is transferred to a substrate that defines the molded product. In general, ribs having a width and height larger than the wall thickness defining the thickness are formed (for example, see Patent Document 2).

[0003] However, this rib is formed with some shrinkage transfer spots and hollow portions in the molded product from the fluid injection portion to the region where the hollow portion is formed (hereinafter referred to as "hollow portion forming region"). There is a problem of deteriorating appearance such as whitening of time. There are also many products where it is difficult to provide ribs due to their function.

[0004] Therefore, in order to eliminate the ribs and improve the appearance of the fluid injection part force of the molded product to the hollow part forming region, the predetermined cavity surface of the hollow molding die extending from the fluid injection part to the hollow part forming region is predetermined. A hollow mold having a heat insulating material in the region has been proposed (see, for example, Patent Document 3).

[0005] This hollow molding die has conventionally been formed with ribs and provided with a heat insulating material at the mold cavity position corresponding to the newly positioned position, thereby delaying cooling compared to the molten resin filled in other regions. Then, a pressurized fluid is injected into the region where the cooling is delayed to form a gas channel.

Patent Document 1: Japanese Patent Publication No. 48-041264

Patent Document 2: Japanese Patent Laid-Open No. 06-278155

Patent Document 3: Japanese Patent Laid-Open No. 07-052183 Disclosure of the invention

Problems to be solved by the invention

[0006] However, this heat insulating material must have a lower thermal conductivity than the mold material! /, So a material different from the mold material must be provided in the mold cavity. There is a problem.

[0007] In other words, a heat insulating material of a material different from the mold material (for example, bakelite, etc.) is used in a severe mold cavities that repeats a high temperature and low temperature cycle and a high pressure and low pressure (atmospheric pressure) pressure cycle. However, there is a problem that the frequency of maintenance of the mold is increased due to peeling or deterioration of the heat insulating material, and the production cost of the hollow molded product is increased.

[0008] Further, since the heat insulating material is thick and difficult to cool, there is a problem that it takes time to solidify the molten resin in a portion in contact with the heat insulating material.

Furthermore, since the heat-insulating material is difficult to process in a complicated manner, there is a problem that a complicated pressurized fluid flow path cannot be easily and inexpensively formed in the molten resin.

[0009] The present invention has been made in view of such conventional problems, and improves the aesthetics without providing ribs on the molded product, and allows fluid injection at a low cost even for complex patterns (shapes). It is an object of the present invention to provide a hollow molding die that can form a hollow portion reaching a hollow space forming region, and can reliably guide a pressurized fluid to a desired position.

Means for solving the problem

[0010] The mold for hollow molding according to claim 1 is characterized in that the injection force of the pressurized fluid into the cavity or a force near the cavity is formed on the cavity surface until the hollow part forming region of the molded product or the vicinity thereof. Since a linear (strip-shaped) surface treatment using materials with different thermal conductivities was performed, a flow path of a pressurized fluid was provided at a desired location inside the molten resin along the linear surface treatment. Can be formed. For this reason, ribs are unnecessary on the front surface or the back surface of the molded product, and the appearance of the molded product can be enhanced. Furthermore, in general, the strength of the portion where the hollow portion is formed is weak in the molded product, but the hollow portion can be formed while avoiding the portion where strength is required.

[0011] Further, since the mold cavity itself is subjected to a thin surface treatment, the mold has durability, and it does not take much time to solidify the molten resin in the surface-treated portion. Furthermore, even with complicated flow path patterns, gas flow paths can be formed in the molten resin easily and inexpensively. Can do.

[0012] The hollow molding die according to claim 2 is characterized in that, in claim 1, since the surface treatment is coating and Z or plating and Z or painting, the surface is complicated by a method such as masking. A processing pattern can be formed. In addition, the adhesion to the mold is strong, and a thin surface treatment pattern can be drawn.

[0013] The hollow molding die according to claim 3 is characterized in that, in claim 2, since the surface treatment is PVD coating or CVD coating, adhesion to the die can be further strengthened. A thin and complicated surface treatment pattern can be drawn.

[0014] A hollow molding die according to claim 4 is the hollow molding die according to claims 1 to 3, wherein a linear wrinkle pattern is formed on the cavity surface of the hollow molding die. Since the surface treatment described above is applied to the portion where the fluid is formed, it is possible to more reliably form the flow path of the pressurized fluid along the surface treatment at a desired location inside the molten resin. .

The invention's effect

[0015] By performing a linear surface treatment on the mold, it is possible to form a gas channel at a desired location inside the molded product without providing ribs on the molded product. And it can reduce weight and improve aesthetics.

BEST MODE FOR CARRYING OUT THE INVENTION

[Surface treatment material]

In the present invention, surface treatment refers to coating, plating, painting, gas nitriding, gas soft nitriding, plasma nitriding, radical nitriding, ion nitriding, salt bath nitriding, nitriding treatment such as tuftride, and gas erosion. Carburizing treatment such as charcoal and plasma carburizing.

[0017] The coating refers to a surface treatment using PVD and CVD, and has the effect of improving the wear resistance and mold release of a mold having a very high hardness.

The materials used for coating are, for example, BN, SiC, Si N (thermal conductivity = 16 W

3 4

/ m-K), SiO, TiN, TiAlN (TiN / AlN), TiN / CrN, W C, TiBN, CrAlNX (

twenty two

X = other elements) CrN, TiCN, HfC, HfN, DLC, TaC, thermal conductivity in the case of DLC single crystal (diamond structure) = 2,000W / mK, a—C: in the case of H Thermal conductivity = 30WZm'K, a—C thermal conductivity = 6WZm'K), A1N (thermal conductivity = 14 W / mK), ZrO (thermal conductivity = 13 W / mK), Al O (thermal conductivity = 16 W / mK)

2 2 3

, MgO, Al O MgO, SiO, Si, W N, BeC, BeO, BeN, BO, Mg C, CrO, Ti

2 3 2 3 2 2

C, ZrO, etc.

2

[0018] Plating refers to dry plating represented by wet plating, thermal spraying, DMD, WPC treatment (Patent No. 1594395) represented by chemical plating or electrical plating, for example, chemical Ni There are metal plating, chemical copper plating, chemical Ag plating, electric Ni plating, electric copper plating, and electric Ag plating. Alternatively, it may be a composite plating in which powders such as BN, SiN, SiC, fluorine resin, silicon resin, etc. are emulsified and suspended in a chemical plating or electric plating bath and simultaneously deposited on the metal surface. Also, dry plating using a method such as spraying by mixing BN, SiN, SiC, or other powder into the alloy is acceptable.

[0019] Painting refers to painting.

Examples of the material used for painting include a paint mainly composed of thermosetting resin. Although the thermal conductivity of the thermosetting resin constituting this paint is low, the thermal conductivity can be further increased by adding a substance generally called a pigment such as titanium oxide, potassium titanate, its whisker, iron oxide, or silica. Can be lowered.

[0020] [Combination of surface treatments]

In the surface treatment in the present invention, two or more of the above-mentioned coating, plating, painting, etc. are combined to apply coating or plating on the plating, or to apply plating on the coating. Alternatively, a multilayer structure may be used, such as coatings with different processing temperatures.

Nitriding carburizing and plating and Z or coating may be combined. In addition, the surface of the mold cavity may be coated with a different material that may be coated or plated on the WPC treatment (trade name).

[0021] As described above, in addition to being able to have a multilayer structure by combining coating, plating, and painting, a complicated pattern can be formed by masking.

In addition, the coating, plating, and painting described above are all thin. Therefore, compared to the mold described in Patent Document 3, the cooling speed of the molten resin in the mold cavity is higher, so the surface of the molded product is used as the costume surface, not only the productivity of the hollow molded product is increased. Can be used.

[Improvement of adhesion of surface treatment]

Surface treatment can be directly coated, plated, and Z or painted on mold cavities, inserts, etc. manufactured using materials such as 55C, SKD, pre-hardened, SUS, Al, Ti, copper alloy materials Is common.

[0023] When coating is applied to the mold surface of the mold, such as chemical plating or electric Ni plating, and coating is applied to the plating, the adhesion of the coating to the mold surface of the mold may increase. is there.

Also, in the painting, if the mold surface of the mold is subjected to a chemical conversion treatment such as zinc phosphate and then painted on it, the adhesion to the mold cavity surface is further increased.

[Method of surface treatment]

Below, PVD, CVD, thermal spraying, ion coating, vacuum deposition, etc. are used in the coating to explain the surface treatment method for applying the surface treatment to the mold cavity surface. When the mold or mold insert is subjected to heat treatment such as quenching or nitriding, PVD with a low processing temperature is desirable.

[0025] In plating, plating or the like is used. When metal plating or chemical conversion treatment is performed, hydrogen embrittlement occurs, so baking at 200 ° C for about 4 hours is desirable. In the case of chemical Ni, baking increases the hardness of the metal!

In painting, painting techniques such as brush painting, spraying, and electrodeposition are used.

These surface treatments can be performed on the mold cavity surface by applying a surface to the surface. When the texture is applied, a heat insulation effect is generated by the air remaining in the recess. Therefore, the effect of the present invention is that the gas channel can be formed at a desired location inside the molded article by using it together with the surface treatment. Furthermore, it can be ensured.

[Effect of surface treatment]

Next, an explanation will be given of the action when these surface treatments are applied to the mold cavity surface. To do.

Although it depends on the width and thickness of the surface treatment, applying TiN or DLC with a thickness of about 5 μm to the mold cavity surface may improve the fluidity of the molten resin in the mold cavity. it can.

[0028] The reason is slightly different between low thermal conductivity and surface treatment, and high thermal conductivity and surface treatment.

[0029] Surface treatment with low thermal conductivity, eg W C, HfC, DLC {

2

Coating with good conductivity (for example, TaC with some diamond structure) and bad coating, plating with chemical NiZ Teflon (registered trademark) powder composite coating, painting with painting, etc. When surface treatment is applied, this surface treatment acts as a heat insulation layer, preventing the heat of the molten resin injected into the mold cavity from escaping to the mold, and thus reducing the temperature of the molten resin (melting) The viscosity of the resin is reduced, and the fluidity of the molten resin existing in the vicinity of the surface-treated portion in the mold cavity can be improved.

[0030] When a part of the mold cavity is subjected to a surface treatment with high thermal conductivity, such as aluminum, silver, copper, BN, BC, AIN, A1C, chemical or electrolytic copper, or silver plating, The heat of the molten resin injected into the mold cavity moves to the surface-treated part and the temperature of only that part rises, preventing the temperature of the molten resin existing in the vicinity of this part from decreasing. As a result, the fluidity of the molten resin existing in the vicinity of the surface-treated portion in the mold cavity can be improved.

[0031] The difference in thermal conductivity depends on the average radius of atoms, interatomic distance, material density, crystal structure, and the like.

For example, substances composed of the same average radius of atoms (for example, DLC, TaC, Si, Ag, Cu, etc. having a diamond structure) can be composed of a single substance. In the case of compounds, those with a specific power of 1 to 1.25 (for example, BN, Al 2 O 3, SiO 2, SiC, AIN, etc.) of the average radius of each atom of the constituent elements have a comparative thermal conductivity. Half of average atoms

2 3 2

Heat with a diameter of 1 · 25 or more (eg W C, TiBN, HfC, HfN, W N ZrO)

2 3 2, 2

Low conductivity. [0032] Thus, in the mold cavity, the temperature difference of the molten resin (fluidity difference = viscosity difference of the molten resin) occurs depending on the presence or absence of the surface treatment. Gas can be guided to the point.

[0033] That is, by applying a surface treatment to part or all of the mold cavity surface, the fluidity of the molten resin in the vicinity of the surface-treated part in the mold cavity is locally improved. Can do. For this reason, due to the cooling delay of the molten resin, it is possible to improve the pressure holding effect during solid molding, the gas pressure holding effect during gas assist molding, and the like. Furthermore, the present invention can also be applied to a place where the draft angle, which is difficult to cope with the texture pattern, is small.

[Thermoplastic resin]

[0034] In the present invention, the thermoplastic resin used as the material of the hollow molded article is not particularly limited as long as it is generally used for molding and is a thermoplastic resin.

Examples of thermoplastic resins include polystyrene resins obtained by polymerizing styrene monomers, such as polystyrene (PS), high impact polystyrene (HIPS, HiPS), nitrile monomers, styrene monomers. Styrenic resin that is a copolymer with a monomer, for example, tali-tolyl 'styrene copolymer (AS), nitrile monomer' styrene monomer 'butadiene rubber Fats, for example, styrene resin such as acrylonitrile 'butadiene' styrene copolymer (ABS, Ab S), polyolefin resin represented by polyethylene (PE), polypropylene (PP), polyphenylene ether (PPE) ), And modified plastics such as PPE, polycarbonate (PC), polyamide (PA), polysulfone (PSF), polyetherimide (PEI), and polymethylol methacrylate (PMMA). Polyester resin such as ethylene terephthalate (PET) or polybutylene terephthalate (PBT), vinyl resin such as salt vinyl (PVC), or a mixture of two or more of these thermoplastic resins ( Polymer blends and polymer alloys).

[Molding method]

[0035] The hollow molding method particularly useful in the present invention is: AGI, GPI, CG M, H ² M from Asahi Kasei Kogyo, GIM from Idemitsu Petrochemical, PFP from Nippon Steel Chemical, Shinpress from UK, G from US AIN Technology, gas such as German air mold, contool, GPI Assist molding method (hollow injection molding method), UCC method of US, USM method, TAF method developed by Toshiba Machine and Asahi Dow, EX—CELL—O company method, Hettinger's foam molding, New -SF, GCP method, Allied Chemical's technique, Co-SF, etc., have supercritical state (body), and are represented by Mucell of US Trexel and A MOTEC of Asahi Kasei. The foam-assisted molding method (foam injection molding method) and the gas-assisted molding method, and the gas-assisted molding of Sumitomo Chemical's SP mold, in-mold molding method, two-color molding, and Sant'Ischie molding. The present invention is also applied to a method in which a molding method is combined.

[0036] Further, when the entire surface of the mold cavity is subjected to a surface treatment, it is conventionally performed by hollow molding, foam injection molding, or solid molding, and melted. Since the fluidity of fat can be improved, it is possible to reduce welds and improve transferability. EXAMPLE 1

[0037] ABS {Technopolymer 130 Natural color (hereinafter referred to as "Techno ABS")} using a 2mm thick spiral flow mold compliant with JIS standard, cylinder temperature; H1ZH2Z H3 / H4 = 220 / 230/220/200 (° C), mold temperature (temperature controller setting temperature); 30 ° C injection pressure setting; 70% (gauge pressure; lOMPa), injection speed setting; 80%, injection time setting 4 seconds, screw rotation speed during measurement; 50 rpm, screw back pressure during measurement; flow length (MFR) formed by IMPa was confirmed.

[0038] As a result, no surface treatment = 455mm, Tanzawa Yakosha Shibo (TH—113) = 476mm, Ti Ν 5

DLC 5 m = 471mm, 25m Teflon (registered trademark) coating = 488mm, polyimide coating 40m = 492mm, Tanazawa Yakosha Shibo (TH — 113) に 5

It showed a 481-mm MFR, and it was found that by applying a surface treatment to the mold cavity surface, the fluidity of the molten resin was improved, as was the case with the embossed pattern.

Example 2

[0039] PS {A & M styrene HF77 natural color (hereinafter referred to as “HF77”)), as in Example 1, cylinder temperature; H1ZH2ZH3ZH4 = 200Z210Z210Z200 (° C), mold temperature Setting temperature); 30 ° C, injection pressure setting; 70% (gauge pressure; 10MP a), injection speed setting; 80%, injection time setting; 4se _C , screw rotation speed during metering; 50rpm, screw back pressure during metering; IMPa was molded and the flow length was confirmed.

[0040] As a result, no surface treatment = 640mm, TH—113 = 666mm, TiN 5

m, DLC 5

TH-113 shows DFR5 m = 672mm, 25 / zm Teflon (registered trademark) coating = 681mm, polyimide coating 40m = 692mm, silver plating 15 πι = 677πιπι, copper plating 15 m = 676mm MFR, gold By applying a surface treatment to the cavity surface of the mold, it was found that the fluidity of the molten resin was improved as in the case where the texture pattern was applied.

Example 3

[0041] POM (polyplastic M270 natural color) was applied to the cylinder temperature in the same way as in Example 1; H 1 / H2 / H3 / H4 = 180/190/180/170 (° C), mold temperature ( Temperature controller set temperature); 40 ° C, injection pressure setting; 70% (gauge pressure; lOMPa), injection speed setting; 80%, injection time setting;

[0042] As a result, no surface treatment = 285 mm, TH—113 = 302 mm, TiN 5 ^ πι = 299ιη m, DLC 5 μm = 289 mm, 25 μm Teflon (registered trademark) coating = 289 mm, polyimide coating 40 μm M = 306mm, silver plating 15 μm = 297mm, copper plating 1 5mm = 2986m MFR, surface treatment on mold cavity surface, the flow of molten resin is the same as when embossed The improvement in performance was a key factor.

Example 4

[0043] Molten molding resin is injected from the resin injection part 43 into the cavity 42 formed by the upper mold 40 (steel type 55C) and the lower mold 41 (steel class 55C) shown in FIG. A hollow molded product 20 shown in FIG. 2 was obtained by the gas assist molding method. Transparent ABS (Toyolac 920) (trade name) manufactured by Toray was used as the molding resin.

[0044] From the gas injection pins 44 and 45 (corresponding fluid injection portions 22 and 23) which are the injection positions of nitrogen gas as the pressurized fluid, the hollow portion forming region 47 to form the hollow portion 24 of the molded product 20 A surface treatment 46 is applied to the mold cavity surface in the fluid flow path forming region 48.

[0045] In this embodiment, a linear D with a width of 15mm is formed on a part of the mold cavity surface of the upper mold 40. Since the LC coating is about 5 m thick, the fluid flow path 25 is about 12-16 mm along the part 46 (corresponding part 21 in the hollow molded product 20) where the coating film is formed. It was confirmed that it was formed with a width. In other words, the shape of the fluid flow path formed in the molded product projected onto the surface of the molded product was substantially the same as the shape of the coating applied to the mold cavity surface.

[0046] As described above, the DLC coating is linearly applied to the cavity surface of the mold, so that the cooling of the molten resin in the DLC coated part is slowed down, and the nitrogen gas enters the molten resin along the coating. It was confirmed that the flow path was formed.

Example 5

[0047] The difference from Example 4 is only that the TiN coating is used on the cavity surface of the mold.

In the case of TiN coating, as in the case of DLC coating, the fluid flow path 25 is formed with a width of about 12 to 16 mm along the coated part 46 (corresponding part 21 in the hollow molded product). I was able to confirm that

[0048] From the above, it was confirmed that the same effect as in the case of DLC coating was obtained by applying a TiN coating linearly to the cavity surface of the mold.

Example 6

[0049] Toyolac 920 was injected into the mold cavity as a molding resin, and a hollow molded product 30 shown in Fig. 3 was obtained by gas assist molding. The mold for forming the hollow molded product 30 (steel grade is KPM1) has a width of 15 mm and a linear W C coating on the surface of the cavity with a thickness of 7 μm.

2

The gas injection pin (not shown) was installed in the fluid injection part 32 and nitrogen gas was injected.

[0050] As a result, the portion in which the W C coating is linearly formed (the corresponding portion in the hollow molded product 30)

2

It was confirmed that the hollow part was formed with a width of about 16 to 20 mm along the minute 31). In other words, even when the molded product is not provided with a gas channel such as a rib, by performing surface treatment on the part of the mold cavity surface corresponding to the part where the hollow part is to be formed in the molded product. It was confirmed that the effect of introducing nitrogen gas was obtained, similar to the gas channel with ribs. Example 7

[0051] Toyolac 920 was injected into the mold cavity as a molding material, and as shown in Fig. 4, the mold (steel grade is KPM1) and half of each of the mold (steel grade KPM1) and the core (hollow molded product 10) 12) Corrosion TiN coating 5m was used to obtain a hollow molded product 10 with a plate thickness of 3mm.

On the back surface of the hollow molded article 10, a rib 13 having a height of 5 mm and a length of 350 mm is formed with the thickness of the base being 60% of the surface on which the rib stands (meat). Further, nitrogen gas as a pressurized fluid was injected from the fluid injection part 14.

[0052] As a result of confirming that the hollow portion 15 is formed in the vicinity of the rib 13, in the portion 12 corresponding to the cavity portion to which the TiN coating is applied, the width of the hollow portion 15 is widened by 18 to 30 mm. On the other hand, in the part without TiN12, it was confirmed that the width of the hollow part 15 was extremely narrow, 5-8 mm. Similar results could be obtained when nitrogen gas was injected from the fluid injection section 11.

From the above, TiN is unlikely to lower the temperature of the molten resin. Therefore, it can be said that it is effective to facilitate injection of pressurized fluid.

Example 8

[0053] In place of the TiN coating in Example 7, Teflon (registered trademark) coating (Teflon (registered trademark) coating) was applied to a part of the cavity surface of the mold (steel type KPM1). At this time, a chemical conversion treatment of zinc phosphate was performed to improve the adhesion of Teflon (registered trademark).

As a result, as in Example 7, the expansion of the hollow portion in the portion 12 corresponding to the cavity portion subjected to Teflon (registered trademark) painting was confirmed.

Example 9

[0054] Even when the TiN coating portion of Example 7 was replaced with copper plating, results similar to those of Example 7 and Example 8 were obtained.

Example 10

[0055] After quenching the SKD61, which is the material of the mold, after tempering at 520 ° C, A part of the cavity surface was coated with TiBN with a thickness of 5 μm by PVD. The hardness before and after coating was measured to be about 48 in HRc, and it was found that there was very little decrease in hardness during PVD coating!

On the other hand, when the heat-treated SKD61 was placed in an atmosphere with a CVD treatment temperature of 1,000 ° C for 30 minutes, the hardness showed HEc = 54.

As a result, it was found that coating with force CVD is also possible.

Example 11

[0056] Using Toyolac 920 as the molding material, it was injected into the mold (the steel type is KPM1) cavity, and as shown in Fig. 5, the mold cavity corresponding to approximately half the surface of the molded product was formed by gas-assisted molding. A 15 mm wide linear pear texture 51 (TH-115) was applied to the part, and a TiN coating of 5 m was applied thereon. A hollow molded product 50 having a thickness of 3 mm was obtained in which a rib 54 having a width of 1.5 mm and a height of 5 mm was provided in the mold cavity corresponding to approximately half of the surface of the molded product. Nitrogen gas as the pressurized fluid was injected from the fluid injection part 52.

The nitrogen gas travels along the embossed 51 formed in a linear shape, and travels along the rib 54 after reaching the rib 54. For this reason, the hollow portion 53 is formed along the embossed portion 51 and the rib 54. As a result of confirming the state of the hollow portion 53, in the portion where the embossed pattern 51 is present, the width force Sl5 to 18 mm of the hollow portion 53 is widened, whereas in the portion where the rib 54 is present, the width of the hollow portion 53 is 5%. It was confirmed to be as narrow as ~ 9mm.

Similar results could be obtained when nitrogen gas was also injected with the edge force of the ribs 54.

[0058] From the above, in the mold cavity, the linear wrinkle pattern formed on the mold cavity and the TiN coating applied thereon are difficult to lower the temperature of the molten resin. If there is an effect, it is possible.

Example 12

[0059] DLC, TiN, WC, polyimide coating, silver plating on the surface of the molding die (L = 350mm, W = 200mm, plate thickness = 2.5mm, the gate is the lower two side gates)

2

We prepared a metal mold with, and confirmed that the occurrence of welds was reduced compared to the case of using techno ABS black and molding with no surface treatment. [0060] The surface of the spiral flow mold described in Example 1 was ion-nitrided, and the fluidity of techno ABS was confirmed under the same molding conditions as in Example 1. As a result, the fluidity of the molten resin was improved to 469mm. It was confirmed.

Example 14

[0061] Using the mold described in Example 12, it was confirmed that the modified PPE containing 30 wt% glass fiber was injection molded and subjected to surface treatment to reduce the float of the glass fiber and increase the appearance gloss. Example 15

[0062] After the mold flow of the spiral flow described in Example 1 was mechanically calored using steel SKD61 and heat-treated to increase the hardness to about HRC60, TIN was reduced to 2 microns as a material having low thermal conductivity. Surface treatment was performed using the ion coating method, and then the material was coated with BN, which is a material with a high thermal conductivity of 3 microns, using the same ion coating method!

The fluidity of techno ABS was confirmed under the same molding conditions as in Example 1. As a result, it was confirmed that the fluidity of the molten resin was improved by 475 mm.

Example 16

In Example 16, only the coating in Example 4 was changed from DLC to CrN, and substantially the same result as in DLC was obtained.

By applying the CrN coating, it was confirmed that cooling of the molten resin in the CrN-coated part was slow, and a nitrogen gas flow path was formed inside the molten resin along the coating.

Example 17

[0064] In Example 17, the coating in Example 4 was changed from DLC to Al 2 O 3 MgO.

2 3 It is a new one.

By applying Al O MgO coating, the inside of the molten resin along the coating

twenty three

It was confirmed that a nitrogen gas flow path was formed.

Example 18

[0065] In Example 18, the core of the mold in Example 4 and the entire surface of the mold were coated with TiN. It was confirmed that, after applying the coating, the linear DLC part was coated with BN, and the flow path of nitrogen gas was formed along the BN coating shape, creating a hollow part.

Example 19

[0066] In Example 19, an O-ring was installed on the PL surface of the mold of Example 12 to form a seal mold, and 1.2 MPa gas counter pressure (GCP) was applied to the mold with air. In this case, techno ABS black was used with foaming resin using 0.3% by mass of sodium hydrogen carbonate as a foaming agent.

As in the case of solid molding in Example 12, it was confirmed that the occurrence of welds was reduced as compared with the case without surface treatment.

Example 20

[0067] Example 20 is for confirming the transferability of the texture pattern by the surface treatment.

The mold cavity of Example 19 was subjected to a texture of about TH-113, and a BN coating was applied on DLC, TiN, WC, BN, and TiN, respectively.

2

[0068] After that, hollow molding was performed using Techno ABS black, and the transfer characteristics of the texture pattern were surface-treated! /, In the case of about 76 to 80%, the same molding conditions However, the transferability of the texture pattern was improved to about 84-91%.

In other words, it was confirmed that the reproducibility of the mold is improved because the fluidity of the molten resin is not impaired by applying the coating.

Example 21

[0069] In each of Examples 4, 5, 6, 8, 9, and 11, substantially the same results can be obtained even if the resin is changed from Toyolac 920 to HF77.

Example 22

[0070] In each of Examples 12, 15, 16, 17, 18, and 19, substantially the same results were obtained even when the resin was replaced with HI PS resin (A & M polystyrene 403R) made of A & M styrene.

Example 23 [0071] Almost the same results were obtained using the composite of Example 14 containing 30% by mass of PC glass fiber, 30% by mass of ABS glass fiber, and 10% by mass of HIPS glass fiber. Obtained

[0072] The above-described embodiments have been illustrated for the purpose of explanation, and the present invention is not limited thereto. From the scope of the claims, the detailed description of the invention, and the drawings, those skilled in the art will understand. As long as it is not contrary to the technical idea of the present invention that can be recognized, changes and attachments can be made.

[0073] In the above-described embodiments, as a linear surface treatment, a force that exemplifies a single linear surface is not limited to these in the present invention. Even if it is a complicated pattern which a linear thing combined, you may give multiple.

[0074] Further, the surface treatment may be performed not only on the mold surface corresponding to the surface of the molded product but also on the mold surface corresponding to the back surface of the molded product. In this case, the pressure holding effect is improved because the temperature of the molten resin is hardly lowered simply by reducing the weld. As a result, the molding temperature of the heating cylinder can be lowered by improving the transferability of molded parts, improving dimensional accuracy, and improving fluidity, and the effects such as energy saving are not only gas-assisted molding but also solid molding and foaming. It can be produced by molding or compression molding.

Industrial applicability

[0075] Even if the molded product is provided with a gas channel by ribs, the same result as that provided by ribs can be obtained by subjecting the molded product to surface treatment such as coating, plating, painting, etc. Therefore, it can be applied to hollow molded articles with improved aesthetics.

Brief Description of Drawings

FIG. 1 is a cross-sectional view showing a hollow molding die. (Example 4, Example 5)

FIG. 2 is a perspective view showing a hollow molded product. (Example 4, Example 5)

FIG. 3 is a perspective view showing a hollow molded product. (Example 6)

FIG. 4 is a perspective view showing a hollow molded product. (Example 7)

FIG. 5 is a perspective view showing a hollow molded product. (Example 11)

Explanation of symbols Hollow molded product Surface treatment Fluid injection part Fluid injection part Hollow part Fluid flow path Surface

Claims

The scope of the claims

[1] In a hollow mold for molding a molded product having a hollow part,

The position of the pressurized fluid injected into the cavity or the force near the cavity on the cavity surface of the mold for hollow molding is the heat of the material for the mold for hollow molding up to or near the hollow formation area of the molded product. Die for hollow molding, characterized by a band-shaped surface treatment using materials with different conductivities

[2] The mold for hollow molding according to claim 1, wherein the surface treatment is coating and Z or plating and Z or painting.

[3] The hollow mold according to claim 2, wherein the coating is a PVD coating or a CVD coating.

[4] A band-like texture pattern is formed on the cavity surface of the hollow molding die,

4. The hollow molding die according to claim 1, wherein the surface treatment is applied to a portion where the texture pattern is formed.