KR20040014343A - Injection molding equipment, component member used for the same, and surface treatment method - Google Patents

Abstract

PURPOSE: An injection molding machine, a constituent member, and a surface treatment method are provided to secure a long service life span and to favorably increase molding efficiency. CONSTITUTION: In an injection molding machine, a portion of a surface contacting with molding resin of a base material(41) forming a resin passage is covered with a protective film(43) made of a diamond-like carbon containing fluorine. A base layer(42) is made of at least one of 4a, 4b, 5a, and 6a groups and formed between the base material and the protective film. A constituent member is a mold or at least one member of a needle, a sprue, a manifold, a heating cylinder, a screw, and a nozzle. The base layer and an intermediate film disposed between the base material and the protective film improve the bonding force of the base material and the protective film and ensure the effect of the protective film for a long time.

Description

Injection molding apparatus, components and surface treatment methods used therein {INJECTION MOLDING EQUIPMENT, COMPONENT MEMBER USED FOR THE SAME, AND SURFACE TREATMENT METHOD}

BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to various injection molding apparatuses and constituent members such as needles, molding dies, sprues, taps, manifolds, heating cylinders, screws, nozzles, and the like. An injection molding apparatus having a protective film excellent in peelability or fluidity of molding resin, a constituent member used for the same, and a surface treatment method.

A needle is disposed inside the nozzle body for injecting the molten resin into the cavity, and the melted resin that has been fed is injected into the cavity from the tip of the nozzle body through a narrow gap formed between the nozzle body and the needle. . The needle is then moved slightly to seal the gate after holding the pressure, and then the resin molded article is taken out from the injection molding apparatus.

Moreover, about the metal mold | die for shaping | molding, following patent document 1 is mentioned, for example.

(Patent Document 1)

Japanese Patent Application Laid-Open No. 1-234214

By the way, the needle or the nozzle body is usually made of steel, and the peelability with the molding resin is poor. Therefore, when gate-sealing with these needles, bubble-shaped protrusions, pins, peeling, etc. are likely to occur in the gate seal of the molded article. Moreover, since the peelability with molding resin is bad, when a molding is complete, resin adheres to the peripheral surface of a needle or the inner surface of a nozzle main body, and when the next injection molding is carried out, the attached resin burns and discolors, and the burnt residue There, it may peel from a needle or a nozzle main body, may flow into a cavity, and may mix in a molded article. As a result, there is a disadvantage in that the product value is lowered or, when severely, the molding is poor and the production yield is lowered.

Moreover, since the fluidity | liquidity of the resin for shaping | molding on the molding die surface is not necessarily favorable, resin with a comparatively small molecular weight is used, and for that reason, the mechanical strength of a molded article may not be enough. In addition, in order to improve the flow of the resin, it is necessary to increase the molding temperature (heater temperature), which results in a disadvantage in that the power consumption increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide an injection molding apparatus with good moldability and long service life by eliminating the disadvantages of the prior art, and various structural members and surface treatment methods used therefor.

1 is a view for explaining an injection part of an injection molding apparatus according to a first embodiment of the present invention;

2 is a view for explaining an injection part of an injection molding apparatus according to a second embodiment of the present invention;

3 is a view for explaining a molding part of an injection molding apparatus according to a third embodiment of the present invention;

4 is a view for explaining a molding part of an injection molding apparatus according to a fourth embodiment of the present invention;

5 is a partially enlarged cross-sectional view showing a state where a protective film is formed on a substrate of the present invention;

6 is a schematic configuration diagram of a sputtering apparatus;

7 is an enlarged perspective view showing a supporting state of a constituent member on a supporting table;

8 is a diagram for explaining an application state of sputter power to a target;

9 is a diagram for explaining the principle of an unbalanced magnetron sputtering method;

10 is a partially enlarged cross-sectional view showing a state where a protective film is formed on a substrate according to a modification of the present invention;

11 is a partially enlarged cross-sectional view showing a surface state of a movable side mold shown in FIG. 4;

12 is an enlarged plan view showing a state of a gate sealing portion when a needle according to an embodiment of the present invention is used;

13 is an enlarged plan view showing a state of a gate seal in the case of using a conventional needle;

14 is a view for explaining a peeling test method;

15 is a view for explaining a peel test method;

16 is a characteristic diagram showing a test result of peelability when ABS resin is used;

17 is a characteristic diagram showing a test result of peelability when a polystyrene resin is used;

18 is a plan view of a test movable mold used for testing the fluidity of the resin in the mold;

It is a characteristic view which shows the result of a fluidity test.

※ Explanation of symbols for main parts of drawing

1: sprue (tango) 2: molten resin

3: manifold 4: nozzle body

5: needle 6: needle guide bush

7: cylinder 8: forming mold

8a: fixed side mold 8b: movable side mold

11: heating cylinder 12: band heater

13: screw 14: check ring

15: check head 16: heating cylinder head

17: open nozzle 21: fixed die plate

22: fixed side mold 23: movable die plate

24: mold mounting plate 25: movable side mold

26: cavity 27: sprue

28: resin injection port 29: nozzle

30: molten resin 31: eject pin

32: stamper 33: fixed side mold

34: movable side mold 35: stamper outer circumference holder

36: cavity 37: gate member

38: gate cut member 39: runner

40: sprue 41: base material

42: base layer 43: protective film

44: interlayer 45: mixed region layer

51: chamber 52: work table

53: support table 54: target for the base layer

55: target for protective film 56: inner magnetic pole

57: outer stimulus 58: magnetic field lines

62: gas piping 64: plasma

65: component 66: prop

67: ceiling

In order to achieve this object, the first means of the present invention, in the injection molding apparatus, a part or all of the surface contacting the molding resin of the base material forming the resin flow path is fluorine-containing diamond-like carbon (hereinafter, Fluorine-containing DLC).

According to a second means of the present invention, in the first means, between the substrate and the protective film, a periodic table of Group 4a (Ti, Zr, Hf), Group 4b (Si, Ge, Sn, Pb), Group 5a (V, Nb, Ta) and a base layer containing at least one element of Group 6a (Cr, Mo, W) as a main component are formed.

A third means of the present invention is a constituent member for use in an injection molding apparatus, wherein part or all of the surfaces in contact with the molding resin are covered with a protective film made of fluorine-containing diamond-shaped carbon.

A fourth means of the present invention is the third means, wherein the structural member is a molding die.

The fifth means of the present invention is the third means, wherein the constituent member is at least one member among a needle, a sprue, a manifold, a heating cylinder, a screw, and a nozzle.

The sixth means of the present invention includes, in the third to fifth means, at least one element of Groups 4a, 4b, 5a, and 6a of the periodic table as a main component between the base material of the structural member and the protective film. It is characterized in that the base layer is formed.

A seventh means of the present invention is the sixth means, wherein the element of the main component of the base layer is at least one element selected from the group of Cr, W, Ti, and Si.

According to an eighth aspect of the present invention, in the sixth or seventh aspect, a mixed region layer of an element constituting the base layer and an element constituting the protective film is formed between the base layer and the protective film. will be.

A ninth means of the present invention is the sixth means, wherein an intermediate film made of diamond-like carbon is formed between the base layer and the protective film.

In a ninth means of the present invention, in the ninth means, a mixed region layer of an element constituting the base layer and an element constituting the intermediate layer is formed between the base layer and the intermediate layer. will be.

An eleventh means of the present invention is a base layer target comprising at least one element of Groups 4a, 4b, 5a, and 6a of the periodic table, a target for carbon, a target for protective film, and a target for the base layer and protective film The base material of the component for injection molding apparatus arrange | positioned facing the target is arrange | positioned in an inert gas,

A protective film is formed by applying a predetermined sputtering power to the target for the base layer to form a base layer on the substrate, and when the film thickness of the base layer reaches a predetermined thickness, gradually lowering the sputter power to the target for the base layer. When the sputter power for the target for the target is gradually raised, and the sputter power for the target for the protective film reaches a predetermined value, the supply of the sputter power to the target for the base layer is stopped, and the fluorine-containing gas is mixed with the inert gas for a predetermined time. By forming a protective film made of fluorine-containing diamond-shaped carbon on the base layer, a mixed region of elements constituting the base layer and elements constituting the protective film is formed between the base layer and the protective film.

A twelfth means of the present invention is a base layer target comprising at least one element of Groups 4a, 4b, 5a, and 6a of the periodic table, a target for carbon and an intermediate film and protective film, the target for the base layer, and The base of the component for injection molding apparatus arranged opposite to the target for the interlayer film and the protective film is disposed in an inert gas, sputtered by applying a predetermined sputter power to the target for the base layer, and a base layer is formed on the base. When the film thickness of the underlying layer reaches a predetermined thickness, the sputtering power of the target for the intermediate layer and the protective film is gradually increased while the sputtering power of the target for the intermediate layer and the protective film is gradually raised, and the sputtering power of the target for the intermediate film and the protective film is predetermined. When the value is reached, the supply of the sputter power to the target for the underlayer is stopped, and sputtering is performed for a predetermined time, so that the diamond is placed on the underlayer. By forming the intermediate film made of de-shaped carbon, a mixed region of the element constituting the base layer and the element constituting the intermediate layer is formed between the base layer and the intermediate film, and then a fluorine-containing gas is mixed with the inert gas for a predetermined time. The sputtering is performed to form a protective film made of fluorine-containing diamond-shaped carbon on the intermediate film.

A thirteenth means of the present invention is the eleventh or twelfth means, wherein the element of the main component of the base layer is at least one element selected from the group of Cr, W, Ti, and Si.

In addition, the "main component" in this invention means the case where the content rate of the element which comprises is more than 50 weight%, and also includes the case of 100 weight%.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described with drawing. 1 is a view for explaining an injection part of the injection molding apparatus according to the first embodiment.

1 is a sprue which supplies molten resin 2, such as ABS resin, to the manifold 3, for example, and 4 is the several nozzle main body (one in FIG. 1) provided in the front-end | tip of the manifold 3; Not shown only in the nozzle body 4, 5 is a needle movably disposed in the nozzle body 4 to gate seal the resin, and 6 holds the needle 5 at the center position of the nozzle body 4; The needle guide bush, 7 is a cylinder incorporating a piston for driving the needle 5, 8 is a molding die, and is composed of a fixed side die 8a and a movable side die 8b.

The molten resin 2 supplied from the sprue 1 is branched in the direction of each mold 8 by the manifold 3, and through the narrow gap between the nozzle body 4 and the needle 5, the nozzle body It is injected into the molding die 8 (cavity) from the tip part of (4), and is gate-sealed by the needle 5 after pressure retention, and a resin molded article is obtained. In this injection molding apparatus, constituent members such as the sprue 1, the manifold 3, the nozzle body 4, the needle 5, the needle guide bush 6, and the molding die 8 are formed with a molten resin for molding ( 2).

FIG. 2 is a view for explaining an injection part of the injection molding apparatus using the screw according to the second embodiment.

In the drawing, 11 is a heating cylinder, 12 is a band heater wound around the outside of the heating cylinder 11, 13 is a screw disposed in the heating cylinder 11 to rotate and move in the axial direction, 14 is the screw 13 A check ring installed at the tip side and movable in the axial direction of the screw 13, 15 is a check head installed at the tip of the screw 13, 16 is a heating cylinder head provided at the tip of the heating cylinder 11, 17 is a heating cylinder It is an open nozzle installed in the head 16.

The resin pellet introduced into the rear end 18 of the heating cylinder 11 from the hopper (not shown) moves the inside of the heating cylinder 11 to the front end side by the rotation of the screw 13, and the heating cylinder 11 (band heater). (12) is plasticized and kneaded with heat from. The sufficiently molten resin passes through the gap between the screw 13 and the check ring 14 and the gap between the check head 15 and the heating cylinder head 16 by the instantaneous movement of the screw 13 in the axial direction. Injection is carried out from the open nozzle 17 into a mold (not shown). In this injection molding apparatus, constituent members such as the heating cylinder 11, the screw 13, the check ring 14, the check head 15, the open nozzle 17 and the like come into contact with the molten resin.

3 is a view for explaining a molding section of the injection molding apparatus according to the third embodiment. In the figure, 21 is a fixed die plate in which the stationary side die 22 is provided, and 23 is a movable die plate in which the movable side die 25 is provided via the die placement plate 24. The movable die plate 23 is driven back and forth (left and right in the figure) by a mold clamping device (not shown), and the mold clamping position and the movable mold (where the movable side mold 25 is in close contact with the fixed side mold 22) The mold opening position separated from the fixed side mold 22 can be taken.

The cavity 26 is formed by the two molds 22 and 25 in a state in which the movable side mold 25 is in close contact with the fixed side mold 22, and the cavity 26 is formed of a gate, a runner, and a sprue 27. ) And communicates with the resin inlet 28, and the nozzle 29 is pressurized to the resin inlet 28. The molten resin 30 injected from the nozzle 29 is filled in the cavity 26 through the sprues 27, and held and cooled. Thereafter, the mold is opened and the eject pin 31 is moved forward to push out the molded product from the movable mold 25. In this molding part, structural members, such as the fixed side metal mold | die 22, the movable side metal mold 25, or a core (not shown), the nozzle 29, etc. come into contact with the molten resin 30 as needed.

4 is a view for explaining a molding section of the injection molding apparatus according to the fourth embodiment. 32 is a stamper made of a nickel material formed on the inner surface of a fine uneven surface corresponding to recording information of a digital versatile disk (DVD), 33 is a fixed side mold, 34 is a movable side mold, and 35 is outside a stamper. It is a circumferential holder. By combining and closing these molding dies, a cavity 36 for forming a molded article (in this embodiment, a DVD substrate) is formed.

The cavity 36 includes a runner 39 and a sprue 40 formed of the gate member 37 provided on the fixed side mold 33 and the gate cut member 38 provided on the movable side mold 34 so as to be movable. ) Is in communication with. Molding resins, such as polycarbonate which have become molten, are injected and filled into the cavity 36 via the sprue 40 and the runner 39.

After the resin has cooled and solidified, the gate cut member 38 is moved upward, cut at the gate cut portion corresponding to the center portion of the molded article, and then the movable mold 34 is moved to open the mold. The DVD board | substrate with which the fine uneven surface of the stamper 32 was transferred is taken out. In addition, 43 is a protective film demonstrated in detail in FIG. 10, and 44 is an intermediate film demonstrated in detail in FIG.

The sprue 1, the manifold 3, the nozzle body 4, the needle 5, the needle guide bush 6, the molding die 8, the heating cylinder 11 and the screw 13 described in the above embodiments. ), Check ring 14, check head 15, open nozzle 17, fixed side mold 22, movable side mold 25, core (not shown), nozzle 29, fixed side mold 33 Constituent members of the injection molding apparatus, such as the movable mold 34, the stamper outer circumferential holder 35, and the like, are, for example, HPM1, 2, 17, 31, 38, 50, PSL, SUS420, 440, SLD, and HAP. Steels, such as SKD11, 61, STAVAX, NAK55, 80, and 101, are selected suitably as a base material.

In the present invention, the protective film according to the present invention is formed on at least one of the constituent members of the injection molding apparatus. Moreover, it is not necessary to form a protective film in all the surfaces which contact the molding resin of the said base material, and may be part.

5 is a partially enlarged cross-sectional view showing a state in which a protective film is formed at least in contact with the molding resin of the substrate. As shown in the figure, a protective film 43 is formed on the substrate 41 via an underlayer 42. The base material 41 is made of steel such as the above-described SKD, on which the periodic table 4a (Ti, Zr, Hf), 4b (Si, Ge, Sn, Pb), 5a (V, Nb, Ta), An underlayer layer 42 having a main component as a main component is formed, at least one of the elements of Group 6a (Cr, Mo, and W), especially at least one element selected from the group of Cr, W, Ti, and Si. A protective film 43 made of fluorine-containing DLC is formed on the layer 42.

In FIG. 5, although the base layer 42 is one layer, you may make it two or more layers as needed, For example, the 1st base layer which consists of Cr is formed on the base material which consists of steel (Fe), A second underlayer made of W may be formed thereon, and a protective film made of fluorine-containing DLC may be formed thereon.

When the ratio (F / C) of fluorine to carbon in the protective film is 0.25 or more, the peelability to the molding resin and the fluidity of the molding resin are good, and as the ratio (F / C) increases, the peelability and fluidity are increased. Improve. However, since the ratio (F / C) increases and the hardness of the protective film tends to decrease, the ratio (F / C) is preferably in the range of 0.3 to 0.9.

This ratio F / C can be controlled by the concentration of fluorine-containing gas such as CF ₄ and C ₂ F ₈ during sputtering described later. Hydrogen may also be included in order to impart toughness to the protective film. In this case, a mixed gas of fluorine-containing gas such as CF ₄ , C ₂ F ₈ and hydrocarbon-based gas such as CH ₄ , C ₂ F ₈ Using this mixing ratio, the hydrogen content in the protective film can be controlled, and the toughness of the protective film improves as the content of hydrogen increases, but the ratio (H / C) is preferably in the range of 0.05 to 0.4. .

Physical deposition (PVD) or chemical vapor deposition (CVD) such as sputtering or ion plating is preferably used for the formation of the underlying layer 42, the protective film 43 and the intermediate film described later.

FIG. 6: is a schematic block diagram of the sputtering apparatus which forms the base layer 42 and the protective film 43 continuously.

As shown in the figure, a work table 52 is provided in the center of the chamber 51, and a plurality of support tables 53 are provided on the work table 52. 7 is an enlarged perspective view showing the support state of the constituent members 65 on the support table 53. As shown in the figure, a support 66 is set up in the center of the support table 53, and the ceiling plate 67 is fixed to the head of the support 66, and a circumference of the ceiling plate 67 is performed. For example, a large number of constituent members 65 of the injection molding apparatus made of needles 5 (see FIG. 1) and the like are suspended. In FIG. 7, an example of cutting off a relatively thin and long structural member 65 like the needle 5 to the ceiling plate 67 is provided. However, when the structural member 65 is relatively large, it is installed on the support table 53 one by one. You may also do it. The work table 52 and the support table 53 are rotated at a constant speed in a predetermined direction by a motor and its power transmission mechanism (both not shown), and the constituent members 65 supported by the support table 53 are also supported. It rotates in accordance with the rotation of the table 53.

Along the outer periphery of the work table 52, the sputter evaporation source 56 in which the plate-shaped base layer target 54 and the protective film target 55 were mounted is provided in substantially equal intervals, respectively. In the case of this embodiment, since the thickness of the base layer 42 is thin compared with the protective film 43, one target 54 for underlay layers and three target 55 for protective films are arrange | positioned. In the case where the base layer is two layers, for example, one target for the first base layer, one target for the second base layer, and two target films 55 for the protective film may be disposed. The target layer 54 for the base layer is made of at least one metal plate selected from the group of Cr, W, Ti, and Si, and the target film 55 for the protective film is made of graphite plate.

In addition, a gas pipe 62 is provided in the chamber 51, and the vacuum degree in the chamber 51 is maintained in the range of 10 ° to 10 ^-1 Pa, and argon (Ar) gas is contained as fluorine-containing inert gas. As the gas, tetrafluoromethane (CF ₄ ), hexafluoroethane (C ₂ F ₆ ), and the like are used. Sputter power is applied to the sputter evaporation source 56 from a sputter power source (not shown) at the timing as described later. The base layer 42 and the protective film 43 are continuously formed while forming the plasma 64 of argon as a whole by the application of this sputter power.

FIG. 8 is a diagram for explaining an application state of sputter power to the targets 54 and 55. As shown in the figure, first, a voltage of 500 W is applied to the target layer target 54 for the base layer (solid line), and the target 55 for the protective film is in an off state (broken line). Plasma is generated by the application of the sputter power, argon ions collide with the target layer 54 for the underlayer, and bounce off the target material, and the sputtered particles are deposited on the base 41 of the constituent member 65 to form the underlayer ( 42). Since the constituent member 65 passes through the front of the base layer target 54 many times while rotating itself, the base layer 42 is formed uniformly as a whole. Sputter power is kept constant until the underlying layer 42 is deposited to approximately a predetermined thickness.

Thereafter, while gradually lowering the sputter power to the target layer 54 for the base layer, the sputter power for the protective film target 55 is gradually increased, and when the power for the target film 55 for the protective film reaches 1000 W, the base layer for the base layer 55 The power to the target 54 is 0W, and then it is controlled so that this state is maintained for a certain time.

The carbon particles bounced off by the collision of argon ions are deposited on the underlying layer 42 to form a DLC film. At this time, when the carbon particles are deposited, the fluorine is also dried together by mixing fluorine-containing gas with Ar gas. A protective film 43 made of DLC is formed. At this time, since the constituent member 65 passes through the front of each of the protective film targets 55 several times while rotating by itself, the protective film 43 is formed uniformly as a whole.

When switching from the formation of the base layer 42 to the formation of the protective film 43, as described above, the sputter power for the target film 55 for the protective film is gradually decreased while gradually reducing the sputter power for the target 54 for the base layer. The raising operation is performed. As a result, the composition of the base layer 42 and the protective film 43 is continuously changed to have a concentration gradient. As a result, the base 41 side of the base layer 42 has a content of approximately 100% of the metal constituting it. 43), the content of metal gradually decreases toward the side, and the content of fluorine-containing DLC increases, and the content of metal and fluorine-containing DLC is approximately half in the middle portion of the base layer 42 and the protective film 43. When the protective film 43 is on the side, the content of the metal component is further reduced, and the content of fluorine-containing DLC is almost 100% near the surface of the protective film 43. Therefore, the boundary between the base layer 42 and the protective film 43 cannot be clearly identified (therefore, in FIG. 5, the vicinity of the boundary between the base layer 42 and the protective film 43 is indicated by a dotted line).

The film thickness of the underlying layer 42 is 0.1 µm to 2 µm, preferably 0.1 µm to 1 µm, and the film thickness of the protective film 43 is 0.1 µm to 5 µm, preferably 0.5 µm to 3 µm, and is too thin. When it is made into a film thickness, it becomes difficult to exhibit favorable peelability and fluidity, and when too thick, the protective film 43 itself will peel easily from the base material 41 side, and the function will be impaired, and therefore the film thickness of the said range will be Recommended.

For example, in the case of the constituent member 65 having a hole, a recess, a convex portion, or the like, the collimator sputtering method in which a lattice-shaped collimator electrode is disposed between the target 54 and 55 is used. The sputtering particles of the component perpendicular to the plane of the hole, the concave portion and the convex portion of 65 can be selectively attached, which is preferable.

FIG. 9 is a view for explaining the principle of an unbalanced magnetron sputtering method suitable for forming the base layer 42, the protective film 43, and the intermediate film described later.

As shown in the figure, an inner magnetic pole 56 that forms a weak magnetic field is disposed at a position opposed to an approximately central portion of the target layer target 54 for the underlayer and the protective film target 55, and the target 54, The outer magnetic pole 57, which forms a strong magnetic field, is disposed at a position opposite to the outer circumference of 55) to form an unbalanced magnetic field.

And while forming the plasma 64, a part of the magnetic force line 58 generated by the powerful outer magnetic pole 57 reaches to the vicinity of the constituent member 65. Plasma ions (e.g., argon ions) and electrons generated during sputtering along this magnetic force line 58 reach the surface of the constituent member 65 more in comparison with normal sputtering, and thus are dense and smooth in plane. One base layer 42, a protective film 43, and an intermediate film can be formed.

10 is a partially enlarged cross-sectional view showing a state where a protective film is formed on a substrate according to a modification of the present invention. As shown in the drawing, an underlayer 42 containing Cr as a main component is formed on a base 41 made of steel such as SKD, and an intermediate film 44 composed of DLC containing carbon and hydrogen as a main component is formed thereon. do.

At this time, the sputter power for the graphite plate (intermediate film and protective film target) for forming the DLC film is gradually increased while the sputter power for the target for the base layer is gradually lowered, so that the boundary between the base layer 42 and the intermediate film 44 is The mixed region layer 45 having a concentration gradient of Cr and DLC is formed. Then, a fluorine-containing gas is supplied from the middle of the formation of the intermediate film 44 to form a protective film 43 made of fluorine-containing DLC on the intermediate film 44.

The film thickness in this embodiment is about 0.1 micrometer in the base layer 42, about 0.2 micrometer in the mixed region layer 45, about 0.7 micrometer in the intermediate film 44, and about 0.5 micrometer in the protective film 43. As shown in FIG. The protective film 43 made of fluorine-containing DLC is not directly formed on the base layer 42, or the intermediate film 44 is provided under the protective film 43. When it is thinner than this protective film 43, there exists a tendency for it to become soft as the whole film.

Therefore, if the intermediate film 44 is provided between the underlayer 42 and the protective film 43 like this embodiment, and the film thickness of the intermediate film 44 is made thicker than the film thickness of the protective film 43, an intermediate film 44 acts as a reinforcement of the protective film 43, resulting in a durable film.

In the case of the injection molding apparatus shown in FIG. 4, since the resin for molding flows in contact with the cavity 36 of the stationary mold 33, the protective film 43 is formed on the surface as shown in FIG. Need to be formed.

On the other hand, the surface of the movable side mold 34 is covered with a stamper 32 and does not contact with the molding resin, but instead has a structure in contact with the stamper 32. Therefore, as shown in FIG. 11, the surface of the movable side metal mold 34 has the base layer 42, the mixed region layer 45, and the intermediate film 44 formed on the base material 41, and the protective film 43 Is not installed. By providing the intermediate film 44 made of DLC on the surface of the base material 41, it is possible to prevent abrasion of the movable side mold 34 due to sliding contact with the stamper 32 due to excellent wear resistance and low friction. In this case, the fluorine-containing DLC protective film 43 may be appropriately formed on the surface of the stamper 32 in contact with the molding resin.

It is also possible to provide a protective film 43 made of fluorine-containing DLC on the outer surface of the movable side mold 34, but since the intermediate film 44 has a stronger mechanical strength than the protective film 43, the movable side mold 34 The outer surface of the intermediate film 44 is better.

12 and 13 are enlarged plan views showing a state of a gate seal in a cartridge case made of ABS resin using the molding apparatus of FIG. 1. 12 shows a needle 5 having a base layer 42 made of W formed on a base material 41 made of SKD, and a protective film 43 made of fluorine-containing DLC formed thereon. Fig. 13 is an enlarged plan view of the gate sealing using a conventional needle made of SKD and having no protective film 43 formed on the surface thereof.

In the case of using a conventional needle, since peelability with resin is not good, as shown in FIG. 13, a bubble-shaped protrusion or a pin is generated in the shield gate part of a molded article, and consequently, the unevenness of the gate part is conspicuous. It is not preferable in appearance.

On the other hand, when the needle in which the protective film 43 which consists of fluorine-containing DLC is formed is used, since peelability with resin is favorable, a bubble-shaped protrusion is hardly found in the shield gate part of a molded article, as shown in FIG. It becomes a planar clean gate part, and there exists a distinct difference in appearance from the conventional thing shown in FIG.

Among the constituent members of the injection molding apparatus, in particular, the needle has a narrow gap between the nozzle body, a considerable high pressure is applied at the time of conveying the molten resin, and the resin temperature is high. In addition, since the protective film 43 of fluorine-containing diamond-like carbon is formed on the surface of the needle because of sliding contact with the needle guide bush 6 (see FIG. 1), the sliding characteristic with the needle guide bush 6 becomes good. Because it is effective.

FIG.14 and FIG.15 is a figure for demonstrating the peeling test method. As shown in FIG. 14, DLC film | membrane 72 of each specification is formed in the surface of the test piece 71 which consists of mirror-processed SUS material (HPM38), and various resin powder is filled in the aluminum tube 73 of 3 mm inside diameter. do. Then, the lower end opening of the aluminum tube 73 stands on the test piece 71 so as to contact the DLC film 72, and is heated to 250 ° C. with a hot plate to bond the aluminum pipe 73 to the test piece 71. .

Next, as shown in FIG. 14, the test piece 71 is set on the base 74 so that the aluminum tube 73 may be horizontal, and the press part 76 of the push pull gauge 75 is 25 mm / min. It descend | falls at the constant speed of, and the stress of a shear direction is applied to the aluminum tube 73. And the pressure strength when the aluminum tube 73 peels from the test piece 71 is evaluated as peel strength. The number of samples in each test is five.

FIG. 16 and FIG. 17 show the results of the peel strength test. FIG. 16 shows the case where ABS resin is used as the resin to be filled in the aluminum tube 73 and FIG. 17 shows the polystyrene resin. In each of the figures, X represents nothing formed on the test piece 71, and an aluminum tube 73 is bonded directly to the mirror surface of SUS by resin, Y forms a DLC film on the test piece 71, and Z represents a test piece. (71) Test results of the formation of the fluorine-containing DLC film of the present invention.

As is apparent from these figures, the (Z) in which the fluorine-containing DLC film of the present invention is formed has a lower peeling strength than that of the other (X, Y), that is, the peeling resistance to the resin is good, and the peeling strength is also excellent. It can be seen that the nonuniformity of is small compared with the other (X, Y).

It is a top view of the movable side metal mold | die used for the fluidity test of resin in a metal mold | die. As shown in the figure, the spiral grooves 82 are formed on the surface of the test movable die 81 as shown in diagonal lines. The spiral grooves 82 have a depth of 0.5 mm and a width of 10 mm. In the middle of the spiral groove 82, all 12 eject pins 83 and 84 are arranged at intervals.

On the other hand, the spiral groove 82 is not formed in the fixed mold for testing, and the surface of the movable die 81 that faces the spiral groove 82 is flat. A resin injection hole is provided at a position corresponding to the eject pin 83 at the center of the fixed side die, and the resin is supplied to the spiral groove 82 by the injection hole.

When the test movable mold and the fixed mold are joined to each other to tighten the mold, when polycarbonate (R1700) is injected from the resin injection hole 83 under the conditions of a molding temperature of 320 ° C., an injection speed of 200 mm / s, and an injection pressure of 200 MPa, It is tested to what extent the resin has flowed out from the central portion of the spiral groove 82 through the spiral groove 82, and the result is shown in FIG.

In FIG. 19, the horizontal axis | shaft has shown the length which the resin flowed out in the metal mold | die, and the vertical axis | shaft has shown the number of times (piece). In the drawing, the white bar graph shows the SUS material (HPM38) mirror-processed on both the movable side mold and the fixed side mold, and the black bar graph shows the mirror surface of the SUS material (HPM38) on both the movable side mold and the fixed side mold The fluorine-containing DLC protective film of the present invention is formed. In addition, 25 shots were taken in each mold, and the frequency distribution thereof was shown.

As apparent from this figure, the present invention in which a fluorine-containing DLC protective film is formed on the surface of the mold has a very good flowability of the resin in the mold even when the spiral groove 82 has a very shallow depth of 0.5 mm. It can be seen that it can sufficiently cope with thin molding.

Particularly, among the members constituting the injection molding apparatus, the molding die has the following characteristics because of good fluidity of the molding resin and good releasability with the molding resin.

. It is possible to use a molding resin having a high molecular weight, and can improve the mechanical properties of the molded article,

. It is possible to lower the molding temperature, thereby reducing the electric power for heating.

. No draw taper is required in the molding die, or the taper angle can be reduced.

. Reduce the number of eject pins,

. Tact (molding cycle time) can be shortened

. Thinner molding is possible,

. Complex shapes can be molded,

. Corrosion resistance of molding die improves,

. There is room for margin of molding condition and stability of molding cycle.

. Since the molding die is not easily damaged, the handleability of the mold is good.

. In the conventional molding die, the surface roughness of the mold has to be lowered in order to maintain the releasability with the molding resin, but it is possible to increase the surface roughness of the mold to make the mold surface mirror surface.

. Since excessive force is not applied when ejecting a formed article, it has such characteristics as less deformation such as warpage.

If the molding resin material is vinyl chloride resin, chlorine gas is used; if flame retardant resins are halogenated compounds such as chlorine or bromine or phosphorus compounds; if ABS resins are vulcanizing agents; polyacetal resin is formic acid; If formalin is a low foaming resin, corrosive gases such as ammonia and carbon monoxide are likely to occur.

However, since the protective film made of the fluorine-containing DLC of the present invention has excellent corrosion resistance, it is possible to prevent the constituent members of the molding apparatus from being eroded by the corrosive gas, to extend the service life of the molding apparatus and to maintain a stable molding cycle at all times. Can be.

The present invention has the above-described configuration, and by covering the surface in contact with the resin with a protective film made of fluorine-containing DLC, the peelability with the resin is improved, the occurrence of bubble-shaped protrusions, pins, peeling, etc. on the surface of the molded article and Melting of resin disappears. In addition, the flow of the resin becomes good, and hence the moldability is improved, so that molding with thin thickness and precision molding are possible.

In addition, the protective film made of fluorine-containing DLC is excellent in corrosion resistance, and the constituent members are not corroded by the corrosive gas generated at the time of molding, thereby extending the service life of the molding apparatus and always maintaining a stable molding cycle.

If an underlayer or an interlayer is provided between the substrate and the protective film, the adhesion between the substrate and the protective film is good, and the above-described effects of the protective film can be effectively exhibited for a long time.

In addition, if a mixed region of the elements constituting the base layer and the elements constituting the protective layer is formed between the base layer and the protective film, and there is no clear interface between the base layer and the protective film, the base layer and the protective film are continuously It is integrated, and eventually, the bonding property of a base material and a protective film becomes strong more, and the effect of a protective film can be exhibited effectively for a long time.

Claims (13)

An injection molding apparatus, characterized in that at least a portion of the surface of the base material forming the resin flow passage in contact with the molding resin is covered with a protective film made of fluorine-containing diamond-shaped carbon. The method of claim 1, An injection molding apparatus, characterized in that a base layer composed mainly of at least one element of Groups 4a, 4b, 5a, and 6a of the periodic table is formed between the substrate and the protective film. A constituent member for use in an injection molding apparatus, wherein at least a portion of the surface contacting the molding resin is covered with a protective film made of fluorine-containing diamond-shaped carbon. The method of claim 3, A structural member for use in an injection molding apparatus, characterized in that the structural member is a molding die. The method of claim 3, And a constituent member is at least one of a needle, a sprue, a manifold, a heating cylinder, a screw, and a nozzle. The method according to any one of claims 3 to 5, The base material which consists of at least 1 element of the periodic table 4a, 4b, 5a, 6a group is formed between the base material of the said structural member, and a protective film, The structure used for the injection molding apparatus characterized by the above-mentioned. absence. The method of claim 6, The element of the main component of the base layer is at least one element selected from the group of Cr, W, Ti, and Si, a constituent member for use in an injection molding apparatus. The method according to claim 6 or 7, A component member for use in an injection molding apparatus, wherein a mixed region layer of an element constituting the base layer and an element constituting the protective film is formed between the base layer and the protective film. The method of claim 6, A structural member for use in an injection molding apparatus, wherein an intermediate film made of diamond-shaped carbon is formed between the base layer and the protective film. The method of claim 9, A component member for use in an injection molding apparatus, wherein a mixed region layer of an element constituting the base layer and an element constituting the intermediate layer is formed between the base layer and the intermediate layer. Injection molding disposed opposite to the base layer target, the protective layer target made of carbon, and the base layer target and the protective layer target mainly composed of at least one element of Groups 4a, 4b, 5a, and 6a of the periodic table. The base material of the component for apparatus is arrange | positioned in an inert gas, Sputtering is performed by applying a predetermined sputtering power to the target for the underlayer, thereby forming a underlayer on the substrate, When the film thickness of the base layer is a predetermined thickness, while gradually lowering the sputter power for the target for the base layer, gradually increases the sputter power for the target for the protective film, When the sputtering power of the target for the protective film reaches a predetermined value, the supply of the sputtering power to the target for the underlayer is stopped, the fluorine-containing gas is mixed with an inert gas, and sputtered for a predetermined time to form a fluorine-containing diamond on the underlayer. By forming a protective film made of carbon, A surface treatment method for a constituent member for use in an injection molding apparatus, wherein a mixed region of an element constituting the base layer and an element constituting the protective layer is formed between the base layer and the protective film. A target for an underlying layer, which is based on at least one element of Groups 4a, 4b, 5a, and 6a of the periodic table, a target for an intermediate film and a protective film made of carbon, The base material of the component for injection molding apparatus arrange | positioned facing the said base layer target and the target for an intermediate film and a protective film is arrange | positioned in inert gas, Sputtering is performed by applying a predetermined sputtering power to the target for the underlayer, thereby forming a underlayer on the substrate, When the film thickness of the base layer reaches a predetermined thickness, the sputter power to the target for the interlayer film and the protective film is gradually increased while gradually lowering the sputter power to the target for the base layer. When the sputtering power of the target for the interlayer film and the protective film reaches a predetermined value, the supply of the sputter power to the target for the base layer is stopped, and sputtering is performed for a predetermined time to form an interlayer made of diamond-shaped carbon on the base layer. Between the layer and the interlayer, a mixed region of elements constituting the underlying layer and elements constituting the interlayer is formed, Next, a fluorine-containing gas is mixed with the inert gas and sputtered for a predetermined time to form a protective film made of fluorine-containing diamond-shaped carbon on the intermediate film, wherein the constituent member is used in an injection molding apparatus. The method of claim 11 or 12, The element of the main component of the base layer is at least one element selected from the group of Cr, W, Ti, and Si, the surface treatment method of the constituent member for use in an injection molding apparatus.