Patent Description:
Foam molding is mainly used to realize weight reduction of automobile parts and electronic products. In foam molding, by forming fine pores inside a molded article by expansion of a chemical foaming agent, the specific gravity of the molded article is reduced, whereby weight reduction can be achieved. However, when foam molding is used, although weight reduction can be realized, an aesthetically pleasing appearance cannot be realized by existing technologies due to gas generated by expansion of foaming gas. Major defects are swirl marks, silver streaks and so on which may be generated by foaming gas. In this case, even when painting is performed, it is very difficult to mask such defects. Accordingly, the formed article could be hardly used as an exterior product. To overcome this problem, a method of covering a foamed product with leather or cloth is used. Also, to prevent swirl marks or silver streaks beforehand from forming on the surface of a molded article, rapid heating/cooling molding (RHCM) or counter-pressure molding has been developed and used. However, there are disadvantages such as high manufacturing costs and difficulty in control or operation. In addition, it is difficult to maintain appearance properties for a desired period.

<CIT> relates to a molding tool for producing molded foam bodies, particularly polyurethane molded foam bodies, by filling a mold with an expandable reactive mixture, whereby the shaping inner surfaces of the tool are provided with a microstructuring with the lotus leaf effect and/or with a durable nonstick coating made of a fluoroplastic or of a diamond-like coating.

<CIT> provides a surface roughness restoring method of a cylindrical mold for molding an elastomer roller capable of restoring the surface roughness, which is lowered by the abrasion accompanied by the molding of a foamed elastomer layer, of the fluoroplastic-containing fluorine coating layer applied to the inner peripheral surface of the mold, which specifies the outer peripheral surface of the foamed elastomer layer of the elastomer roller formed by the foam molding of the foam forming material in the mold, at a low cost. As a solution, the mold is heat-treated to be held at <NUM>-<NUM> for <NUM> and subsequently quenched to <NUM>-<NUM> to restore the fluoroplastic-containing fluorine coating layer.

<CIT> is directed to preventing the generation of a flow line on the side of the sole of a shoe while improving the flow of an injected resin, in molding the sole of a shoe by injecting a foamed polyurethane into the cavity formed by assembling a plurality of molds, by applying a fluoroplastic processing to the inner surface of a side mold and the upper surface of a sole mold. According to <CIT>, the surface of an aluminium mold is first sandblasted and degreased and then baked and subjected to PTFE coating. For the latter, a "Polyflon TEF" dispersion (trade name Daikin Ind. ) was painted, dried and then baked at a temperature of <NUM> for <NUM> minutes and then painted with "Neoflon FEP" dispersion (trade name Daikin Ind. ), dried and baked at <NUM> for <NUM> minutes.

The use of fluoropolymer coatings such as PFA (perfluoroalkoxy) and PTFE (polytetrafluoroethylene) for alumunium moulds used in polyurethane foam moulding is disclosed in "<NPL>.

The properties of four different types of fluoropolymers as mould surface coatings were studied in "<NPL>.

Therefore, the present invention has been made in view of the above problems, and it is one object of the present invention to provide an injection mold, an injection molding machine including the injection mold, and a method of manufacturing an injection-molded product using the injection molding machine. According to the present invention, even without special equipment, an injection-molded product having an aesthetically pleasing appearance without surface appearance defects such as swirl marks, silver streaks, glass fiber (G/F) floating, and weld lines may be manufactured. In addition, the injection mold of the present invention may be used semi-permanently without replacing parts or device. Therefore, according to the present invention, manufacturing process time and costs may be reduced, and manufacturing process precision may be improved.

The above and other objects can be accomplished by the present disclosure described below.

In accordance with one aspect of the present invention, provided is an injection mold including a mold having a mold surface on which one or more deposition layers are laminated, wherein a first deposition layer comprises polytetrafluoroethylene (PTFE), and a second deposition layer comprises perfluoroalkoxy (PFA) resin, wherein the first deposition layer has a thickness of <NUM> to <NUM> and wherein the second deposition layer has a thickness of <NUM> to <NUM> pm, and wherein the two or more deposition layers are sinter-hardened deposition layers; an injection molding machine including the injection mold; and a method of manufacturing an injection-molded product using the injection molding machine.

As apparent from the foregoing, the present invention advantageously provides an injection mold, an injection molding machine including the injection mold, and a method of manufacturing an injection-molded product using the injection molding machine. According to the present invention, even without special equipment such as a rapid heating/cooling molding apparatus or a counter-pressure molding apparatus, an injection-molded product having an aesthetically pleasing appearance without surface appearance defects such as swirl marks, silver streaks, glass fiber (G/F) floating, and weld lines can be manufactured. In addition, the injection mold of the present invention can be used semi-permanently without inconvenience of cutting and installing a coating film every time a process is performed. Accordingly, manufacturing process time and costs can be reduced, and manufacturing process precision can be improved.

Hereinafter, an injection mold, an injection molding machine including the injection mold, and a method of manufacturing an injection-molded product using the injection molding machine according to the present invention will be described in detail.

The present inventors confirmed that, when a fluororesin insulation layer was formed on a mold surface by using a deposition method in which fluororesin powder such as Teflon is sintered on a mold surface at high temperature and then curing is performed, the mold surface was instantaneously heated by using a heat source of a resin being shot and filled, and formation of a solidified layer of the resin was instantaneously delayed. By this, the shape of the mold surface was intactly transferred to the injection-molded resin by the growth pressure of foaming cells while the foaming rate of general foaming was secured. Thus, it was confirmed that an aesthetically pleasing appearance without swirl marks or silver streaks was secured. Based on these results, the present inventors conducted further studies to complete the present invention.

The injection mold of the present invention includes a mold having a mold surface on which one or more deposition layers are laminated, wherein a first deposition layer comprises polytetrafluoroethylene (PTFE), and a second deposition layer comprises perfluoroalkoxy (PFA) resin, wherein the first deposition layer has a thickness of <NUM> to <NUM> and wherein the second deposition layer has a thickness of <NUM> to <NUM> pm, and wherein the two or more deposition layers are sinter-hardened deposition layers. In this case, even without special equipment, an injection-molded product having an aesthetically pleasing appearance without swirl marks or silver streaks may be manufactured. In addition, the injection mold may be used semi-permanently without inconvenience of cutting and installing a thermal insulation means every time a process is performed. In addition, manufacturing process time and costs may be reduced, and manufacturing process precision may be increased.

Hereinafter, the technical features of each configuration of the injection mold of the present invention will be described in detail, but each technical feature may independently define the configuration of the injection mold of the present invention, or two or more technical features may simultaneously define the configuration of the injection mold of the present invention.

For example, a total thickness of the deposition layers may be <NUM> to <NUM> pm, preferably <NUM> to <NUM> pm, more preferably <NUM> to <NUM> pm, still more preferably <NUM> to <NUM> pm, most preferably <NUM> to <NUM>. Within this range, by thermal insulation, cooling delay effect may be improved, and thus an injection-molded product having an aesthetically pleasing appearance may be manufactured. In addition, processing time may be reduced, economy may be improved, and appearance properties may be excellent.

In the present invention, the thickness of a deposition layer may be measured using a thickness measurement method commonly used in the art to which the present invention pertains. In one embodiment, as shown in <FIG>, thickness may be determined simply by measuring the height difference between a deposited portion (a coating layer) and a non-deposited portion (a portion to which tape is attached).

The first deposition layer has a thickness of <NUM> to <NUM> pm, preferably <NUM> to <NUM>. Within this range, adhesion may be excellent, and thermal insulation effect may be improved. In addition, processing time may be reduced, and economic efficiency may be excellent.

The second deposition layer has a thickness of <NUM> to <NUM> pm, preferably <NUM> to <NUM> pm, most preferably <NUM> to <NUM>. Within this range, a desired level of thermal insulation may be achieved, processing time may be reduced, and economic efficiency and appearance properties may be excellent.

For example, the deposition layer may be formed in one or more layers, preferably two or three layers, more preferably two layers. In this case, a desired level of thermal insulation may be fully achieved, processing time may be reduced, and economic efficiency and appearance properties may be excellent.

For example, the deposition layer may be formed by applying a coating paint in a liquid or powder form onto a mold surface using spray coating, dip coating, spin coating, or the like and then performing heat treatment or sinter drying at <NUM> or more or <NUM> to <NUM>, preferably <NUM> to <NUM>, more preferably <NUM> to <NUM>.

For example, the injection mold may be a foam injection mold or a non-foam injection mold, i.e., a general injection mold. In this case, even without special equipment such as a high speed heating/cooling molding apparatus or a counter-pressure molding apparatus, a foam or general injection-molded product having an aesthetically pleasing appearance without surface appearance defects such as swirl marks, silver streaks, G/F floating, and weld lines may be manufactured.

The deposition layers are sinter-hardened deposition layers. In this case, a desired level of thermal insulation may be achieved, and adhesion and durability may be excellent.

The first deposition layer includes polytetrafluoroethylenes (PTFEs). In this case, surface lubrication properties may be improved, and a seizure phenomenon may be prevented. Accordingly, occurrence of a seizure phenomenon on a mold surface due to gas generated during molding may be prevented, thereby reducing molding defects and increasing the cleaning cycle of a mold.

The second deposition layer includes perfluoroalkoxy (PFA) resins. In this case, thermal insulation effect and appearance properties may be excellent.

For example, the mold surface may include a mold surface of a fixed side plate, a mold surface of a mobile side plate, or both, and may be appropriately selected depending on required properties of an injection-molded product and economic efficiency without particular limitation.

For example, the fixed side plate may include a sprue, a runner, a gate, and a cavity side, and the mobile side plate may include a core side and an ejector.

For example, the gate may be a side gate.

Unless specifically defined herein, other components that are involved with methods of manufacturing a non-foam injection mold or a foam injection mold; a non-foam injection molding machine or a foam injection molding machine; and a non-foam (general) injection-molded product or a foam injection-molded product are not particularly limited if they are techniques commonly used in the art to which the present invention pertains may be used. In the present specification, description thereof is omitted to explain the present invention clearly.

The injection mold of the present invention will be described with reference to the accompanying drawings.

<FIG> schematically illustrates an injection mold according to the present invention and a method of manufacturing an injection-molded product according to the present invention, and <FIG> shows an example of a fixed side plate of an injection mold before and after a deposition layer is formed according to the present invention. <FIG> includes images of the front side (formed at a non-deposited surface of a mobile side plate) and the back side (formed at a deposited surface of a fixed side plate) of an injection-molded product (molded article) manufactured by performing foam molding using the injection mold of <FIG> having a fixed side plate on which a deposition layer is formed. Referring to <FIG>, in contrast to the surface of the molded article formed at the non-deposited surface, the surface of the molded article formed at the deposited surface has an aesthetically much more pleasing appearance.

Referring to <FIG>, in the left side of the upper image, a fixed side plate is shown, and in the right side of the upper image, a mobile side plate is shown. When a molten resin composition is fed through a sprue from a nozzle on the left side and a mold cavity is filled with the molten resin composition, in the fixed side plate on which the deposition layer according to the present invention is formed, a mold surface is instantaneously heated by a heat source of the molten resin composition, formation of a solidified layer is instantaneously delayed by thermal insulation effect, the shape of the mold surface is intactly transferred to the molten resin composition by the growth pressure of foaming cells while the foaming rate of general foaming is secured, and an injection-molded product without swirl marks or silver streaks is manufactured. Then, the mobile side plate moves to eject the injection-molded product from the injection mold. The lower left image schematically shows a mold surface (marked as Naked surface) on which the deposition layer according to the present invention is not formed, and the lower right image schematically shows a mold surface (marked as Insulation layer) on which the deposition layer according to the present invention is formed. In the case of the mold surface, shown on the right side, on which the deposition layer is formed, as described above, due to thermal insulation effect, formation of a solidified layer is instantaneously delayed, and thus the shape of the mold surface is intactly transferred onto the surface of an injection-molded product by the growth pressure of foaming cells, thereby ensuring a surface having an aesthetically pleasing appearance without swirl marks or silver streaks. In the drawings, the red part in the plate indicates the molten resin composition being filled, and illustration of the runner and the gate connected from the sprue to the cavity is omitted.

Referring to <FIG>, the left image is a fixed side plate (before mold deposition) on which a deposition layer is not formed, and the right image is a fixed side plate (after mold deposition) on which a deposition layer is formed. To manufacture the fixed side plate, as shown in the right, on which a deposition layer is formed, the fixed side plate on the left side was subjected to cleaning processes such as degreasing and ultrasonic cleaning and then coated with polytetrafluoroethylene (PTFE) powder using spray coating, dip coating, or spin coating. Then, the fixed side plate was sintered by heating at <NUM> or more, more specifically <NUM> to <NUM>, and coated with perfluoroalkoxy (PFA) resin powder using spray coating, dip coating, or spin coating, followed by heat drying at <NUM> or more, more specifically <NUM> to <NUM>. In this case, the thickness of a cavity was <NUM> to <NUM>. A mobile side plate corresponding to the fixed side plate is not shown in the drawings. Since the design of the mobile side plate depends on the shape of the fixed side plate, it is apparent to those skilled in the art, and therefore illustration of the mobile side plate is omitted to avoid any inconvenience.

The injection molding machine of the present invention is an injection molding machine including an injection mold, an injection apparatus, and an actuator, and the injection mold includes the above-described injection mold.

The injection molding machine of the present invention shares technical features with the above-described injection mold, and thus repeated description will be omitted.

For example, the injection apparatus includes a hopper through which a resin composition is fed, a heating cylinder for plasticizing and moving the fed resin composition and screw which are one or more. Heating cylinders commonly used in non-foam (general) injection molding machines or foam injection molding machines may be used as the heating cylinder of the present invention without particular limitation. For example, the heating cylinder may include a heater mounted outside the cylinder to supply heat into the cylinder to melt a fed resin composition and a nozzle for spraying a molten resin composition into an injection mold.

For example, the screw may consist of a screw head; a non-return valve; and a continuous or discontinuous screw body.

Valves for preventing backflow of a plasticized resin composition, i.e., a molten resin composition, in a heating cylinder used in an injection molding machine may be used as the non-return valve of the present invention without particular limitation. For example, the non-return valve may include a check ring.

The continuous screw body is a screw body in which a flight is formed continuously without disconnection in the middle, preferably a screw body in which a flight is formed continuously without disconnection over a feed zone, a transition zone, and a metering zone. In this case, a fed resin composition may be easily plasticized. The discontinuous screw body is a screw body in which a flight is disconnected in the middle.

The thickness of the cavity may be adjusted depending on the design of an injection-molded article without particular limitation. For example, the cavity may have a thickness of <NUM> to <NUM>, <NUM> to <NUM>, or <NUM> to <NUM>. Within this range, mechanical properties may be excellent, and an aesthetically pleasing appearance may be secured.

In the present invention, cavity thickness refers to the height of a space in the vertical direction from the bottom of a plate.

Drive motors applicable to general injection molding machines may be used as the actuator of the present invention without particular limitation. For example, the actuator may include a hydraulic cylinder and a hydraulic motor for screw rotation.

A method of manufacturing an injection-molded product according to the present invention includes a step of injection-molding a resin composition using the above-described injection molding machine. According to the method of the present invention, even without special equipment such as a rapid heating/cooling molding apparatus or a counter-pressure molding apparatus, an injection-molded product having an aesthetically pleasing appearance without swirl marks, silver streaks, weld lines, or G/F floating may be manufactured. In addition, the injection molding machine may be used semi-permanently without inconvenience of cutting and installing a coating film every time a process is performed. Accordingly, manufacturing process time and costs may be reduced, and manufacturing process precision may be improved.

In the injection molding, an injection flow rate is preferably <NUM> cc/s or more, more preferably <NUM> to <NUM> cc/s, still more preferably <NUM> to <NUM> cc/s, still more preferably <NUM> to <NUM> cc/s, still more preferably <NUM> to <NUM> cc/s, most preferably <NUM> to <NUM> cc/s. Within this range, an injection-molded product having an aesthetically pleasing appearance may be manufactured. For reference, an injection flow rate may be specified by a user when inputting molding conditions in an injection molding machine.

For example, the resin composition may include <NUM> parts by weight of a thermoplastic resin; <NUM> to <NUM> parts by weight or <NUM> to <NUM> parts by weight of a filler; and <NUM> to <NUM> parts by weight or <NUM> to <NUM> parts by weight of additives. Within this range, reinforcement effect may be obtained, and an aesthetically pleasing appearance may be secured.

Fillers commonly used in the art to which the present invention pertains may be used as the filler of the present invention without particular limitation. For example, the filler may include one or more selected from the group consisting of mineral fillers, glass fibers, carbon fibers, carbon black, and carbon nanotubes (CNTs). Preferably, the filler includes glass fibers. In this case, reinforcement effect may be obtained, and an aesthetically pleasing appearance may be secured.

As another example, the filler may be a master batch including a carrier resin and filler components. Thermoplastic resins that may be molded into foam injection-molded products or injection-molded products may be used as the carrier resin without particular limitation. For example, the carrier resin may be selected within a range of thermoplastic resins according to the present invention. For example, the filler components may be pigments, or the like. In this case, the filler components may be included in the master batch in an amount of <NUM> to <NUM> % by weight or <NUM> to <NUM> % by weight. Within this range, desired effects may be fully expressed without deterioration in other physical properties.

For example, when the filler is carbon black, carbon black may be included in an amount of <NUM> to <NUM> parts by weight, <NUM> to <NUM> parts by weight, or <NUM> to <NUM> parts by weight. Within this range, reinforcement effect may be obtained, and an aesthetically pleasing appearance may be secured.

As another example, when the filler includes one or more selected from the group consisting of mineral fillers, glass fibers, carbon fibers, and carbon nanotubes (CNTs), the filler may be included in an amount of <NUM> to <NUM> parts by weight, preferably <NUM> to <NUM> parts by weight, more preferably <NUM> to <NUM> parts by weight, most preferably <NUM> to <NUM> parts by weight. Within this range, reinforcement effect may be obtained, and an aesthetically pleasing appearance may be secured.

Preferably, the additives may include one or more selected from the group consisting of lubricants, impact modifiers, antioxidants, UV stabilizers, and chemical foaming agents. In this case, an aesthetically pleasing appearance may be achieved, and desired effects of the additives may be fully expressed.

As another example, the additives may be included in an amount of <NUM> to <NUM> parts by weight, <NUM> to <NUM> parts by weight, or <NUM> to <NUM> parts by weight. Within this range, an aesthetically pleasing appearance may be achieved, and desired effects of the additives may be fully expressed.

For example, the chemical foaming agent may be an inorganic blowing agent. In this case, appearance properties may be excellent.

For example, the inorganic blowing agent may include one or more selected from the group consisting of sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium carbonate, and ammonium carbonate without particular limitation. In this case, appearance properties may be excellent.

Thermoplastic resins that may be molded into foam injection-molded products or non-foam (general) injection-molded products may be used as the thermoplastic resin of the present invention without particular limitation. For example, the thermoplastic resin may include one or more selected from the group consisting of polypropylene (PP) resins, ABS resins, ASA resins, PBTs, PA6, PA66, polycarbonates (PCs), PC/ABS alloys, polymethyl methacrylates (PMMAs), polyesters, SAN resins, PSs, PVCs, and polyethylene (PE) resins. In this case, an aesthetically pleasing appearance may be achieved while maintaining the intrinsic properties of a resin.

For example, the injection molding may be foam molding performed according to a short shot molding method. In this case, a foam product having an aesthetically pleasing appearance without surface appearance defects such as swirl marks, silver streaks, G/F floating, and weld lines may be manufactured.

In the present invention, short shot molding methods commonly used in the art to which the present invention pertains may be used as the short shot molding method of the present invention without particular limitation. For example, the short molding method may be a method of filling a plasticized (i.e., molten) foam molding resin composition into a cavity and completing molding by cell growth.

In addition, the injection molding may be foam molding performed according to a core-back molding method in which a cavity is filled with a molten foam resin composition, a mobile side mold, i.e., a core, pulls back, and molding is completed by cell growth. In this case, a foam product having an aesthetically pleasing appearance without swirl marks or silver streaks may be manufactured.

In the present description, configuration that may be commonly employed in the art to which the present invention pertains is not described, but such a configuration may be easily selected by those skilled in the art as necessary, and thus, the present invention is not affected thereby.

A foam molding resin composition containing <NUM> parts by weight of an ABS resin (AF365F, LG Chemical Co. ), <NUM> parts by weight of a milled glass fiber as a filler, and <NUM> parts by weight of LP338 (DONGJIN Co. ) as a blowing agent was fed batchwise into a general injection apparatus including a hopper, a cylinder, and a screw, and melting and kneading were performed at a molding temperature of <NUM>. Then, according to injection flow rates and mold temperatures shown in Table <NUM> below, the resin composition was injected into an injection mold including a fixed side plate, shown in <FIG>, on which a deposition layer is formed, and a mobile side plate (not shown) corresponding to the fixed side plate, and cells were grown by foaming according to a short molding method to obtain a final foam product. As described above, on the fixed side plate, a first deposition layer having a thickness of <NUM> was formed of polytetrafluoroethylene (PTFE), and then a second deposition layer having a thickness of <NUM> was formed of a perfluoroalkoxy (PFA) resin. In this case, by mirror-processing the mobile side plate without deposition of a fluororesin, the effect of the deposition layer according to the present invention may be confirmed by comparing the appearances of the front and back sides of the injection-molded product. In addition, specifications of an injection molding machine used in the injection molding are as follows. Maximum injection speed: <NUM>/s (<NUM> cc/s); maximum clamping force: <NUM> Ton; screw diameter: <NUM>; and maximum injection pressure: <NUM>,<NUM> bar.

A manufacturing process was performed in the same manner as in Example <NUM>, except that injection flow rates shown in Table <NUM> below were applied.

A manufacturing process was performed in the same manner as in Example <NUM>, except that a foam molding resin composition containing <NUM> parts by weight of a polypropylene resin (SEETEC H7700), <NUM> part by weight of carbon black MB (PP base, carbon content: <NUM> % by weight) as a filler, and <NUM> parts by weight of LP338 (DONGJIN Co. ) as a blowing agent was used instead of the foam molding resin composition of Example <NUM>.

A manufacturing process was performed in the same manner as in Example <NUM>, except that the injection mold used in Example <NUM> was replaced by an injection mold including a hole forming core pin (other conditions were the same), and injection flow rates shown in Table <NUM> below were applied.

A manufacturing process was performed in the same manner as in Example <NUM>, except that a general injection molding resin composition containing <NUM> parts by weight of a polypropylene resin (SEETEC H7700) and <NUM> parts by weight of a long glass fiber (LUFLO LG2400, LG Chemical Co. ) as a filler was used instead of the foam molding resin composition of Example <NUM>, and a general injection molding method was used instead of the short molding method.

A manufacturing process was performed in the same manner as in Example <NUM>, except that a general injection molding resin composition containing <NUM> parts by weight of a polypropylene resin (SEETEC H7700) and <NUM> parts by weight of a glass fiber (LUPOY SC2502, LG Chemical Co. ) as a filler was used instead of the foam molding resin composition of Example <NUM>, and a general injection molding method was used instead of the short molding method.

A manufacturing process was performed in the same manner as in Example <NUM>, except that a fixed side plate on which a <NUM> to <NUM> thick first deposition layer formed of a polyether ether ketone (PEEK) and a <NUM> to <NUM> thick second deposition layer formed of a polyether ether ketone (PEEK) were formed was used, injection flow rate was set to <NUM> cc/s, an acrylate-styrene-acrylonitrile resin (ASA LI941, LG Chemical Co. ) as a general injection molding resin was used instead of the foam molding resin composition, and a general injection molding method was used instead of the short molding method.

A manufacturing process was performed in the same manner as in Example <NUM>, except that, instead of the ASA resin of Example <NUM>, a composition containing <NUM> parts by weight of a polypropylene (SEETEC H7700) resin and <NUM> parts by weight of a glass fiber (LUPOY SC2502, LG Chemical Co. ) was used.

A manufacturing process was performed in the same manner as in Example <NUM>, except that, instead of the ASA resin of Example <NUM>, a polycarbonate (PC) resin (LUPOY PC GP1000MU, LG Chemical Co. ) was used.

A manufacturing process was performed in the same manner as in Example <NUM>, except that, instead of the fixed side plate of Example <NUM>, a fixed side plate on which only a <NUM> thick PTFE first deposition layer is formed was used, injection flow rate was set to <NUM> cc/s, and a general injection molding resin composition containing <NUM> % by weight of polyamide <NUM> (PA6) and <NUM> % by weight of a glass fiber (G/F) was used instead of the foam molding resin composition.

A manufacturing process was performed in the same manner as in Example <NUM>, except that a general injection molding resin composition containing <NUM> % by weight of polyamide <NUM> (PA6) and <NUM> % by weight of a glass fiber (G/F) was used.

A manufacturing process was performed in the same manner as in Example <NUM>, except that, instead of the general injection molding resin composition of Example <NUM>, a polyester-based thermoplastic elastomer (Keyflex-BT 1028D, LG Chemical Co. ) was used.

A manufacturing process was performed in the same manner as in Example <NUM>, except that, instead of the general injection molding resin composition of Example <NUM>, a long fiber-reinforced thermoplastic resin (LUFLO LG2250B, LG Chemical Co. ) containing <NUM> % by weight of a long fiber was used.

A manufacturing process was performed in the same manner as in Example <NUM>, except that <NUM> parts by weight of a chemical blowing agent was fed, and foam injection molding was performed according to a short shot molding method.

Both surfaces of each of the foam products manufactured in Examples <NUM> to <NUM> were photographed, and the images were enlarged to visually confirm whether swirl marks, silver streaks, G/F floating, or weld lines were generated. The results are shown in Tables <NUM> to <NUM> below and <FIG>.

As shown in Table <NUM> and <FIG>, since the surface of an injection-molded product formed by a mold surface (a fixed side plate) on which the deposition layer formed of a fluororesin according to the present invention was formed was insulated, a mold surface was indirectly heated by a heat source of a molten resin composition, and generation of a solidified layer was instantaneously delayed. Accordingly, compared to the surface of an injection-molded product formed by a non-deposited (marked as Naked) mold surface (a mobile side plate) in which cooling proceeded as soon as a molten resin composition contacted the mold surface because no deposition layer was formed, on the surface of an injection-molded product formed by a mold surface on which the deposition layer formed of a fluororesin according to the present invention was formed, the number of swirl marks and silver streaks was greatly reduced, or no swirl marks and no silver streaks were generated. In addition, overall cycle time was not affected. In particular, when injection molding was performed at an injection flow rate of <NUM> cc/s or more, no swirl marks and no silver streaks were generated, indicating that appearance was greatly improved.

As shown in Table <NUM> and <FIG>, since the surface of an injection-molded product formed by a mold surface (a fixed side plate) on which the deposition layer formed of a fluororesin according to the present invention was formed was insulated, a mold surface was indirectly heated by a heat source of a molten resin composition, and generation of a solidified layer was instantaneously delayed. Accordingly, compared to the surface of an injection-molded product formed by a non-deposited mold surface (a mobile side plate) in which cooling proceeded as soon as a molten resin composition contacted the mold surface because no deposition layer was formed, the number of swirl marks and silver streaks was greatly reduced, or no swirl marks and no silver streaks were generated. In addition, overall cycle time was not affected. In particular, when injection molding was performed at an injection flow rate of <NUM> cc/s or more, no swirl marks and no silver streaks were generated, indicating that appearance was greatly improved.

As shown in Table <NUM> and <FIG>, since the surface of an injection-molded product formed by a mold surface (a fixed side plate) on which the deposition layer formed of a fluororesin according to the present invention was formed was insulated, a mold surface was indirectly heated by a heat source of a molten resin composition, and generation of a solidified layer was instantaneously delayed. Accordingly, compared to the surface of an injection-molded product formed by a non-deposited mold surface (a mobile side plate) in which cooling proceeded as soon as a molten resin composition contacted the mold surface because no deposition layer was formed, no weld lines were generated, or no G/F floating occurred, indicating that appearance was excellent.

As shown in Table <NUM> and <FIG>, compared to the surface (marked as Naked surface) of an injection-molded product formed by a non-deposited mold surface (a mobile side plate), on the surface (a coating surface) of an injection-molded product formed by a mold surface (a fixed side plate) on which two PEEK resin deposition layers were formed, no gate marks and no silver streaks were generated, and no G/F floating occurred, indicating that appearance was excellent. Referring to <FIG>, in the images of the front sides (formed at a non-deposited (marked as Naked) surface of a mobile side plate) of injection-molded products manufactured by injection molding in Reference Examples <NUM> to <NUM>, the portions indicated by a dotted circle clearly showed that gate marks, G/F floating, and silver streaks were generated. In contrast, it was confirmed that the back side (formed at a deposited (coated) surface of a fixed side plate) of the product had no appearance defects such as gate marks.

As shown in Table <NUM> and <FIG> and <FIG>, compared to the surface (marked as Naked) of an injection-molded product formed by a non-deposited mold surface (a mobile side plate), the surface (marked as Coated) of an injection-molded product formed by a mold surface (a fixed side plate) on which a single PTFE resin deposition layer according to the present invention was formed had no G/F floating, indicating that appearance was greatly improved.

(Evaluated as good when there were no gate marks, no G/F floating, and no silver streaks on the surface of an injection-molded product, and evaluated as poor when gate marks, G/F floating, or silver streaks were generated) As shown in Table <NUM> and <FIG>, compared to the surface (marked as Naked surface) of an injection-molded product formed by a non-deposited mold surface (a mobile side plate), on the surface (marked as Coated surface) of an injection-molded product formed by a mold surface (a fixed side plate) on which a single PTFE resin deposition layer according to the present invention was formed, no marks were generated and no G/F floating occurred, indicating that appearance was excellent.

Referring to <FIG>, even when appearance was not good because an injection material contained a lot of additives as in Example <NUM>, when a mold including a single PTFE resin deposition layer according to the present invention was used, appearance was greatly improved.

Claim 1:
An injection mold, comprising:
a mold having a mold surface on which two or more deposition layers are laminated,
wherein a first deposition layer comprises polytetrafluoroethylene (PTFE), and a second deposition layer comprises perfluoroalkoxy (PFA) resin,
wherein the first deposition layer has a thickness of <NUM> to <NUM> and wherein the second deposition layer has a thickness of <NUM> to <NUM> pm, and
wherein the two or more deposition layers are sinter-hardened deposition layers.