JP2012035427A

JP2012035427A - In-mold coating method

Info

Publication number: JP2012035427A
Application number: JP2010175053A
Authority: JP
Inventors: Seito Noguchi; 聖人野口; Susumu Horinaka; 進堀中; Tomohiko Shigihara; 智彦鴫原; Kenichi Nakajo; 賢一中條; Shoichiro Negishi; 正一郎根岸; Masayuki Yamaguchi; 賢之山口
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2010-08-04
Filing date: 2010-08-04
Publication date: 2012-02-23

Abstract

PROBLEM TO BE SOLVED: To provide an in-mold coating method which can improve the adhesion of a coating material and a resin molding even without using special equipment and a mold.SOLUTION: In the in-mold coating method including the injection step of injecting a coating material for coating the surface of the resin molding into the mold and the dwelling injection step of injecting the coating material into the mold while pressure in the mold obtained in the injection step is made to be close to a target value, the dwelling injection step comprises a standby step in which the injection of the coating material into the mold is stopped, and a pressure drop in the mold by the contraction of a resin is expected when the pressure in the mold exceeds the target value in the standby step and the adjustment step in which the coating material is injected until the pressure in the mold reaches the target value when the pressure in the mold is below the target value.

Description

本発明は、樹脂成形と平行して金型内に被覆材を注入し、樹脂成形品の表面を被覆材でコーティングする型内被覆方法に関する。 The present invention relates to an in-mold coating method in which a coating material is injected into a mold in parallel with resin molding and the surface of a resin molded product is coated with the coating material.

従来の型内被覆方法としては、樹脂成形品の表面に被覆材を被覆するために、樹脂成形品の表面が被覆材に対し、その注入・流動圧力に耐え得る適正硬化または固化の時点で、成形型をそのままの状態に保持しながら、成形型内表面と樹脂成形品との境界に、所要の注入速度パターンで多段の可変速度により被覆材を注入して樹脂成形品の表面を被覆する工程と、被覆材を硬化させる工程とを有する型内被覆方法が知られている（例えば、特許文献１参照）。 As a conventional in-mold coating method, in order to coat the surface of the resin molded product with a coating material, the surface of the resin molded product is properly cured or solidified to withstand the injection / flow pressure against the coating material. A process of covering the surface of a resin molded product by injecting a coating material at a variable injection speed with a required injection speed pattern at the boundary between the inner surface of the mold and the resin molded product while holding the mold as it is. An in-mold coating method including a step of curing the coating material is known (for example, see Patent Document 1).

また、樹脂成形品と被覆材との密着性を向上させるために、金型内の圧力を目標値に保つ手段として、被覆材を金型内に注入するための被覆材注入シリンダが前進動作と後退動作を繰り返し、金型内へ被覆材を注入したり金型内の被覆材を吸引したりして金型内の圧力を制御する型内被覆方法が知られている。 In order to improve the adhesion between the resin molded product and the coating material, as a means for maintaining the pressure in the mold at a target value, a coating material injection cylinder for injecting the coating material into the mold is moved forward. An in-mold coating method is known in which the pressure in the mold is controlled by repeating the retreating operation, injecting the coating material into the mold, or sucking the coating material in the mold.

特開平６−３２８５０４号公報JP-A-6-328504

しかし、特許文献１に記載の技術においては、樹脂成形品の硬化が被覆材注入の条件になっているため、樹脂の硬化時間を必要とし、樹脂の硬化後に被覆材を注入するためサイクルタイムが長くなってしまうという問題がある。また、被覆材を定量供給するため、樹脂の収縮にバラツキが発生した場合には対応することができない点や十分な密着性を得ることができない点などから成形不良が発生する虞があるという問題がある。 However, in the technique described in Patent Document 1, since the curing of the resin molded product is a condition for injecting the coating material, the curing time of the resin is required, and the cycle time is long because the coating material is injected after the resin is cured. There is a problem of becoming longer. In addition, since the coating material is supplied in a fixed quantity, there is a possibility that defective molding may occur due to inability to cope with variations in resin shrinkage or inadequate adhesion. There is.

また、被覆材注入シリンダの前進・後退を繰り返す方法では、目標値の近傍で圧力変化が大きくなり、目標値から下がり過ぎると成形樹脂と被覆膜の密着性の低下や被覆膜欠けなど外観品質に悪影響を及ぼす。その対応として、目標値を高く設定すると、成形型パーティングからの被覆材漏れ、リブ等肉厚変化部のスプリングバックデフォームが発生するという問題がある。 Also, with the method of repeatedly moving the coating material injection cylinder forward and backward, the pressure change increases near the target value, and if it falls too low from the target value, the adhesiveness between the molding resin and the coating film decreases or the coating film is missing. Adversely affects quality. As a countermeasure, if the target value is set high, there is a problem that the coating material leaks from the mold parting and the spring back deforms at the thickness changing portion such as a rib.

本発明は、従来の技術が有するこのような問題点に鑑みてなされたものであり、その目的とするところは、特殊な設備、金型を用いなくても被覆材と樹脂成形品の密着性を高めることができる型内被覆方法を提供しようとするものである。 The present invention has been made in view of such problems of the prior art, and the object of the present invention is to provide adhesion between a coating material and a resin molded product without using special equipment or a mold. It is an object of the present invention to provide an in-mold coating method capable of increasing the resistance.

上記課題を解決すべく本発明は、樹脂成形品の表面を被覆する被覆材を金型内に注入する注入工程と、この注入工程で得た金型内の圧力を目標値に近づけた状態で被覆材を金型内に注入する保圧注入工程を備えた型内被覆方法において、前記保圧注入工程は、前記注入工程で金型内の圧力が目標値を超えた場合には、被覆材の金型内への注入を停止して樹脂の収縮による金型内の圧力低下を待つ待機工程と、この待機工程で金型内の圧力が目標値より低くなった場合には、金型内の圧力が目標値になるまで被覆材を注入する調整工程からなるものである。 In order to solve the above problems, the present invention provides an injection process for injecting a coating material for covering the surface of a resin molded product into a mold, and the pressure in the mold obtained in the injection process is close to a target value. In the in-mold coating method including a holding pressure injecting step of injecting the covering material into the mold, the holding pressure injecting step is performed when the pressure in the mold exceeds a target value in the injecting step. Stopping the injection of mold into the mold and waiting for the pressure drop in the mold due to resin shrinkage, and if the pressure in the mold becomes lower than the target value in this standby process, It consists of the adjustment process which inject | pours a covering material until the pressure of becomes a target value.

また、前記待機工程と前記調整工程を繰り返して金型内の圧力を目標値に近づけることができる。 Further, the pressure in the mold can be brought close to the target value by repeating the standby step and the adjustment step.

本発明によれば、注入工程後における金型内の圧力変化を低く抑えることができるので、樹脂と被覆材との密着性の低下防止及び外観品質の低下防止を可能にすることができる。 According to the present invention, the pressure change in the mold after the pouring step can be kept low, so that it is possible to prevent the adhesion between the resin and the covering material from being lowered and the appearance quality from being lowered.

本発明に係る型内被覆方法を実施する装置の構成図Configuration diagram of apparatus for carrying out in-mold coating method according to the present invention 被覆材供給装置の構成図Configuration diagram of the coating material supply device 溶融樹脂射出工程の説明図Explanatory drawing of molten resin injection process 各注入工程の説明図で、（ａ）は定量注入工程、（ｂ）は定圧注入工程、（ｃ）保圧注入工程It is explanatory drawing of each injection | pouring process, (a) is a fixed-quantity injection | pouring process, (b) is a constant pressure injection | pouring process, (c) Holding pressure injection | pouring process 金型内の圧力波形図Pressure waveform diagram in the mold 樹脂成形品の表面に被覆材がコーティングされた状態の説明図Explanatory drawing of the state where the surface of the resin molded product is coated with a coating material

以下に本発明の実施の形態を添付図面に基づいて説明する。本発明に係る型内被覆方法を実施する装置は、図１に示すように、固定金型１、可動金型２、スプルー３、被覆材４を金型１，２内に注入する被覆材供給装置５などを備えてなる。固定金型１と可動金型２により、樹脂成形品６を成形するためのキャビティ７が形成される。また、固定金型１にはキャビティ７内の圧力を検出する圧力センサ８が設置されている。９はスプルー３に溶融樹脂１０を供給する射出成形機のノズルである。 Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, the apparatus for carrying out the in-mold coating method according to the present invention supplies a coating material for injecting a fixed mold 1, a movable mold 2, a sprue 3 and a coating material 4 into the molds 1 and 2. The apparatus 5 is provided. A cavity 7 for molding the resin molded product 6 is formed by the fixed mold 1 and the movable mold 2. The fixed mold 1 is provided with a pressure sensor 8 for detecting the pressure in the cavity 7. Reference numeral 9 denotes a nozzle of an injection molding machine that supplies the molten resin 10 to the sprue 3.

被覆材供給装置５は、図２に示すように、被覆材タンク１１、ポンプ１２、注入ガン（インジェクタ）１３、コントローラ１４などを備えて構成されている。なお、ポンプ１２の替わりに注入シリンダを用いることもできる。被覆材供給装置５は、被覆材タンク１１に貯留してある被覆材４を所望の圧力で所望の量だけキャビティ７に供給することができる。また、被覆材供給装置５は、圧力センサ８の検出信号をフィードバックして、キャビティ７内の圧力が所望値になるまで、または所望の範囲内になるよう被覆材４をキャビティ７に供給することもできる。 As shown in FIG. 2, the coating material supply device 5 includes a coating material tank 11, a pump 12, an injection gun (injector) 13, a controller 14, and the like. An injection cylinder can be used in place of the pump 12. The coating material supply device 5 can supply the coating material 4 stored in the coating material tank 11 to the cavity 7 in a desired amount at a desired pressure. Further, the coating material supply device 5 feeds back the detection signal of the pressure sensor 8 and supplies the coating material 4 to the cavity 7 until the pressure in the cavity 7 reaches a desired value or within a desired range. You can also.

以上のように構成される装置を用いる本発明に係る型内被覆方法は、図３に示すように、先ず固定金型１と可動金型２によりキャビティ７を形成し、このキャビティ７に射出成形機のノズル９から供給される溶融樹脂１０を、スプルー３を介して射出し、樹脂成形品６を成形する（溶融樹脂射出工程）。 In the in-mold coating method according to the present invention using the apparatus configured as described above, a cavity 7 is first formed by a fixed mold 1 and a movable mold 2 as shown in FIG. The molten resin 10 supplied from the nozzle 9 of the machine is injected through the sprue 3 to form the resin molded product 6 (molten resin injection process).

次いで、溶融樹脂射出工程で樹脂成形品６にスキン層が形成された段階で、図４（ａ）に示すように、樹脂成形品６と固定金型１により形成される隙間１６に、被覆材供給装置５がポンプ１２を駆動して注入ガン１３から所定量の被覆材４を注入する（定量注入工程）。 Next, at the stage where the skin layer is formed on the resin molded product 6 in the molten resin injection process, as shown in FIG. 4A, a coating material is formed in the gap 16 formed by the resin molded product 6 and the fixed mold 1. The supply device 5 drives the pump 12 to inject a predetermined amount of the covering material 4 from the injection gun 13 (quantitative injection process).

また、被覆材４の定量注入工程の替わりに定圧注入工程を適用することができる。定圧注入工程は、溶融樹脂射出工程で樹脂成形品６にスキン層が形成された段階で、図４（ｂ）に示すように、樹脂成形品６と固定金型１により形成される隙間１６に、被覆材供給装置５がポンプ１２を駆動して注入ガン１３からキャビティ７内の圧力が目標値Ｐ_Ｒになるまで被覆材４をキャビティ７に注入する。 Moreover, a constant pressure injection process can be applied instead of the quantitative injection process of the covering material 4. The constant pressure injection process is a stage in which the skin layer is formed on the resin molded product 6 in the molten resin injection process, and as shown in FIG. 4B, the gap 16 formed between the resin molded product 6 and the fixed mold 1 is formed. , coating material supply device 5 injects the covering material 4 in the cavity 7 from the injection gun 13 by driving the pump 12 until the pressure in the cavity 7 becomes the target value P _R.

次いで、図４（ｃ）に示すように、被覆材供給装置５が定量注入工程又は定圧注入工程におけるキャビティ７内の最大圧力Ｐ_Ｈと目標値Ｐ_Ｒとを設定すると共に、キャビティ７内の圧力が目標値Ｐ_Ｒ以上に維持されるようポンプ１２を駆動して注入ガン１３から被覆材４をキャビティ７に注入する（保圧注入工程）。 Then, as shown in FIG. 4 (c), together with the coating material supply device 5 sets a maximum pressure P _H and the target value P _R in the cavity 7 in the metering injection process or pressure injection process, the pressure in the cavity 7 There injecting coating material 4 in the cavity 7 from the injection gun 13 by driving the pump 12 to be maintained at or above the target value P _R (coercive insufflation step).

保圧注入工程は、図５に示すように、注入工程（定量注入工程又は定圧注入工程）でキャビティ７内の圧力が目標値Ｐ_Ｒを超えた場合には、ポンプ１２による被覆材４のキャビティ７への注入を停止し、樹脂の収縮によるキャビティ７の圧力低下を待つ待機工程と、この待機工程でキャビティ７内の圧力が目標値Ｐ_Ｒより低くなった場合には、キャビティ７内の圧力が目標値Ｐ_Ｒになるまでポンプ１２を駆動して被覆材４を注入する調整工程からなる。 Coercive insufflation step, as shown in FIG. 5, the injection step when the pressure in the cavity 7 has exceeded the target value P _R is (quantitative implantation process or pressure injection process), the cavity of the covering material 4 by the pump 12 stop injection into 7, and the standby step of waiting for the pressure drop in the cavity 7 by the resin shrinkage, when the pressure in the cavity 7 becomes lower than the target value P _R in the waiting step, the pressure in the cavity 7 There consisting adjustment step of injecting the coating material 4 by driving the pump 12 to a target value P _R.

そして、待機工程と調整工程を交互に繰り返して、キャビティ７内の圧力が目標値Ｐ_Ｒに近づくように制御される。また、キャビティ７内の圧力が目標値Ｐ_Ｒと最大圧力Ｐ_Ｈの間になるように制御される。すると、図６に示すように、樹脂成形品６の表面（意匠面）６ａに被覆材４がコーティングされる。 Then, by repeating alternately the standby step and the adjusting step, the pressure in the cavity 7 is controlled so as to approach the target value P _R. Also controlled so that the pressure in the cavity 7 is between the target value P _R and the maximum pressure P _H. Then, as shown in FIG. 6, the coating material 4 is coated on the surface (design surface) 6 a of the resin molded product 6.

このように、保圧注入工程において、キャビティ７内の圧力変化を小さく抑えると共に、キャビティ７内の圧力が目標値Ｐ_Ｒを下回らないように制御されるので、樹脂成形品６と被覆膜４の密着性低下を防止し、成形型パーティングからの被覆材４漏れ、リブ等肉厚変化部のスプリングバックデフォームの発生を防止することができる。 Thus, in coercive insufflation step, the suppress the pressure change in the cavity 7, the pressure in the cavity 7 is controlled so as not to fall below the target value P _R, coating a resin molded article 6 film 4 It is possible to prevent the coating material 4 from leaking from the mold parting and the occurrence of spring back deformation at the thickness changing portion such as a rib.

本発明によれば、特殊な設備、金型を用いなくても被覆材と樹脂成形品の密着性を高めることができ、且つヒケなどの不具合がなくなり品質が大幅に向上する型内被覆方法が提供され、利用拡大が期待される。 According to the present invention, there is provided an in-mold coating method that can improve the adhesion between a coating material and a resin molded product without using special equipment and a mold, and eliminates defects such as sink marks and greatly improves quality. Provided and expected to expand usage.

１…固定金型、２…可動金型、３…スプルー、４…被覆材、５…被覆材供給装置、６…樹脂成形品、７…キャビティ、８…圧力センサ、９…ノズル、１０…溶融樹脂、１１…被覆材タンク、１２…ポンプ、１３…注入ガン、１４…コントローラ、１６…隙間。 DESCRIPTION OF SYMBOLS 1 ... Fixed metal mold, 2 ... Movable metal mold, 3 ... Sprue, 4 ... Coating material, 5 ... Coating material supply apparatus, 6 ... Resin molded product, 7 ... Cavity, 8 ... Pressure sensor, 9 ... Nozzle, 10 ... Melting Resin, 11 ... coating material tank, 12 ... pump, 13 ... injection gun, 14 ... controller, 16 ... gap.

Claims

An injection process for injecting a coating material that covers the surface of the resin molded product into the mold, and a process for injecting the coating material into the mold with the pressure in the mold obtained in this injection process close to the target value. In the in-mold coating method including the pressure injection process, the holding pressure injection process stops the injection of the coating material into the mold when the pressure in the mold exceeds the target value in the injection process. Waiting process to wait for pressure drop in the mold due to resin shrinkage, and if the pressure in the mold becomes lower than the target value in this standby process, the coating material is used until the pressure in the mold reaches the target value. An in-mold coating method characterized by comprising an adjusting step of injecting.

The in-mold coating method according to claim 1, wherein the pressure in the mold is brought close to a target value by repeating the standby step and the adjusting step.