KR20130041891A - Process for producing mold - Google Patents

Abstract

Fibrillation of the surface of the molded article which consists of a resin composition containing liquid crystalline resin is suppressed, and the manufacturing method of the metal mold | die for obtaining the molded article which has the outstanding external appearance is provided. By deriving the relationship between the temperature near the cavity surface of the liquid crystalline resin filled in the mold and the holding time of the liquid crystalline resin in the mold by thermal conductivity analysis, the resin temperature near the cavity surface in which the surface layer is not formed on the skin layer of the molded article. The holding time range of the temperature range and the holding time is derived, and a heat insulating layer satisfying the temperature range and the holding time range is installed in the mold.

Description

Mold manufacturing method {PROCESS FOR PRODUCING MOLD}

The present invention relates to a method for producing a mold.

A group of plastics called engineering plastics is being replaced by metal parts with high strength. Among them, a group of plastics called liquid crystalline resins is melted while maintaining a crystal structure. The high strength based on such crystal structure is one of the characteristics of liquid crystalline resin. In addition, since the crystal structure of the liquid crystalline resin does not change significantly during solidification, the volume change during melting and solidification is small. As a result, the liquid crystalline resin has an advantage that the molding shrinkage is small and the dimensional accuracy of the molded article is excellent.

Taking advantage of the above-mentioned advantages of high strength and dimensional accuracy, the liquid crystalline resin composition is used for precision instrument parts. However, in the case of precision instruments and optical instruments, minor waste and dust affect the performance of the apparatus. For this reason, components used in precision instruments and optical instruments, such as camera module components, are ultrasonically cleaned using water or the like during their manufacture to remove small debris, oil, dust, etc. adhering to the surface of the components. do. However, since the molded article formed by molding the liquid crystalline resin composition has a particularly large molecular orientation at the surface portion, a surface layer is formed on the skin layer by a conventional molding method, and the surface is relatively easy to fibrillate. For this reason, if the surface of a molded article is peeled off, it will become a factor of the falling-out thing (garbage). Thus, since generation | occurrence | production of garbage etc. becomes a problem, it is very difficult to ultrasonically wash the molded article formed by shape | molding a liquid crystalline resin composition.

As described above, the surface layer which causes the generation of garbage is formed on the skin layer because the molecular orientation is particularly large on the surface of the molded article. Thus, as a method of not forming the surface layer which is easy to be fibrillated, there exists a method of shape | molding at the mold temperature of 200 degreeC or more. According to this method, fibrillation can be suppressed, but the molding cycle is very long, which leads to problems such as lowering of productivity and deterioration of retention of resin. A molded article comprising a liquid crystalline polymer and a fibrous filler as a molded article having improved surface properties, the flat part having a rising width of the surface roughness (Ra) value obtained by a specific surface tape peeling test of 0.4 µm or less, characterized in that Molded articles are disclosed (Patent Document 1).

According to the method of patent document 1, it is useful as a component of an electrical, electronic device, or optical device, and it is said that the generation of surface particles (foreign material) can be prevented. Thus, when the technique of patent document 1 is used, surface characteristics can be improved.

However, as described in the Example of patent document 1, the foreign material generation in patent document 1 is a foreign material which arises when the surface is wash | cleaned by stirring gently for 1 minute in pure water. Since it is difficult to suppress surface generation itself by improvement of the surface characteristic by the method of patent document 1, when a molded article is exposed to intense conditions, such as ultrasonic cleaning, a lot of foreign substances generate | occur | produce.

1. Japanese Unexamined Patent Publication No. 2008-239950

This invention is made | formed in order to solve the above subject, The objective is the fibrillation of the surface of the molded article which consists of a resin composition containing liquid crystalline resin is suppressed, and the manufacturing method of the metal mold | die for obtaining the molded article which has the outstanding external appearance is suppressed. It is to offer.

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies in order to solve the above problems. As a result, the thermal conductivity analysis derives the relationship between the temperature near the cavity surface of the liquid crystalline resin filled in the mold and the holding time in the mold of the liquid crystalline resin, thereby preventing the surface layer from being formed on the skin layer of the molded article. It was found that the above problems can be solved by deriving a temperature range of the resin temperature near the surface and a holding time range of the holding time, and providing a heat insulating layer satisfying the temperature range and the holding time range in the mold. More specifically, the present invention provides the following.

(1) The manufacturing method of the metal mold | die for manufacturing the molded article which consists of liquid crystalline resin composition containing liquid crystalline resin WHEREIN: The temperature of the vicinity of the cavity surface of liquid crystalline resin filled in the metal mold | die, and holding | maintenance in the metal mold | die of liquid crystalline resin By deriving the relationship with time by thermal conductivity analysis, the temperature range of the temperature near the surface of the cavity and the holding time range of the holding time where the surface layer is not formed on the skin layer of the molded article are derived, and the temperature range and the holding time are obtained. A thermal insulation layer satisfying a range is provided, and the thermal conductivity analysis is performed by using a mold having a thermal insulation layer formed on the surface of the cavity, using the specific gravity, specific heat, thermal conductivity, and thermal diffusivity of the material constituting the mold and the liquid crystalline resin as parameters. The manufacturing method of the metal mold | die to perform.

(2) The manufacturing method of metal mold | die of (1) whose said temperature range is 230 degreeC or more, and the said holding time range is 0.3 second or more.

(3) The method for producing a mold according to (1) or (2), wherein the thermal conductivity analysis determines a material, a mounting position, and a shape of a range heat insulating layer.

(4) The said heat insulation layer is a manufacturing method of the metal mold | die of any one of (1)-(3) whose heat conductivity is 0.3 W / m * K or less and thickness is 60 micrometers or more.

(5) The method for producing a mold according to any one of (1) to (4), wherein the heat insulation layer contains at least one resin selected from polybenzoimidazole, polyimide, and polyether ether ketone.

(6) The manufacturing method of metal mold in any one of (1)-(4) whose said heat insulation layer is a ceramic material comprised from porous zirconia.

(7) The method for producing a mold according to any one of (1) to (5), wherein the heat insulation layer has a metal layer on its surface.

When the molded article which consists of a resin composition containing liquid crystalline resin is manufactured using the metal mold | die manufactured by this invention, fibrillation of the surface of a molded article is suppressed even by ultrasonic washing, and the molded article which has the outstanding external appearance can be obtained.

1: is a figure which shows typically the cross section of the metal mold | die with which the heat insulation layer was formed, (a) is a schematic diagram of the cross section of the division metal mold | die in which the heat insulation layer was formed in the whole cavity surface, (b) the division in which the heat insulation layer was formed in a part of cavity surface. It is a schematic diagram of the cross section of a metal mold | die, (c) is a schematic diagram of the cross section of the divided metal mold | die in which the metal layer was formed on the heat insulation layer.
FIG. 2: is a schematic diagram of the cross section of the split metal mold with a heat insulation layer for demonstrating the thickness of a heat insulation layer, the thickness of a cavity, and the thickness of a metal mold | die.
3 is a diagram showing a relationship between the temperature near the cavity surface and the holding time under a plurality of molding conditions.
4 is a diagram showing a mold used in Example 1. FIG.
FIG. 5 is a diagram showing the relationship between the temperature of the resin at a depth of 7 μm from the cavity surface in Example 1 and the holding time of the resin in the mold.
FIG. 6 is a diagram showing a mold used in Example 2. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail. This invention is not limited to the following embodiment.

The manufacturing method of the metal mold | die of this invention derives the relationship between the temperature of the cavity surface of the liquid crystalline resin filled in the metal mold | die, and the retention time in the metal mold | die of a liquid crystalline resin by thermal conductivity analysis, and the surface layer is formed on the skin layer of a molded article. The temperature range of the temperature near the cavity surface and the holding time range of the holding time so as not to be formed are derived, and at the time of molding, a heat insulating layer satisfying the temperature range and the holding time range is provided in the mold. The thermal conductivity analysis is carried out using a mold having a heat insulating layer formed on the surface of the cavity, using specific gravity, specific heat, thermal conductivity, and thermal diffusivity of the material constituting the mold and the liquid crystalline resin as parameters.

Molding conditions in which the surface layer formed on the skin layer exist by using the relationship between the temperature near the cavity surface of the liquid crystalline resin filled in the mold and the holding time in the mold of the liquid crystalline resin derived by thermal conductivity analysis. Distinguish molding conditions that do not exist. The easily lowering of the resin temperature near the cavity surface can be distinguished because it affects whether or not a surface layer is formed. In addition, by forming a heat insulation layer in the mold such that the relationship between the temperature near the cavity surface and the holding time exhibits a desired behavior, it is possible to obtain a mold capable of producing a molded article having an excellent appearance since the fibrillation of the surface does not easily occur. have.

Hereinafter, the manufacturing method of the metal mold | die of this invention is demonstrated in detail.

<Crystals of resin materials>

The type of liquid crystalline resin is not particularly limited as long as the resin material is a resin composition containing liquid crystalline resin. However, especially when a liquid crystalline resin occupies 50 mass% or more with respect to the whole resin composition, a surface layer is easy to form especially. In addition, additives such as other resins, antioxidants, pigments, stabilizers, inorganic fillers, and the like can be blended into the resin composition in a range that does not impair the effects of the present invention. As specific liquid crystalline resin, the liquid crystalline resin (liquid crystalline polymer) of Unexamined-Japanese-Patent No. 2010-106165 is mentioned, for example.

<Setting of the insulation layer>

Installation of a heat insulation layer first derives the temperature range and holding time range of resin of the cavity surface vicinity in which a surface layer is not formed on the skin layer of a molded article (1st process).

Then, a heat insulating layer is provided in the mold so as to satisfy the temperature range and the holding time range (second step).

Hereinafter, it divides into a 1st process and a 2nd process, and demonstrates the manufacturing method of the metal mold | die of this invention.

<1st process>

In a 1st process, the relationship between the temperature of resin of the cavity surface vicinity of the liquid crystalline resin filled in the metal mold | die, and the retention time in the metal mold | die of liquid crystalline resin is derived by thermal conductivity analysis. The thermal conductivity analysis is performed here using the metal mold | die with which the heat insulation layer was formed in the surface of a cavity, and the specific gravity, specific heat, thermal conductivity, and thermal diffusivity of the material and liquid crystalline resin which comprise a metal mold | die as parameters. Specifically, the above relationship is derived as follows.

First, the parameters used when conducting thermal conductivity analysis will be described. In order to suppress the fall of the resin temperature of the cavity surface vicinity, a heat insulation layer is used. Here, in order to consider the heat transfer of the resin flowing into the mold, it is necessary to consider the thermal conductivity of the heat insulating layer and the heat capacity of the heat insulating layer. Therefore, it is necessary to make the thermal properties of specific gravity, specific heat, thermal conductivity, and thermal diffusivity of the material constituting the mold and the liquid crystalline resin a parameter. Enter these parameters for thermal conductivity analysis.

Next, the metal mold | die with which the heat insulation layer was formed in the surface of a cavity is demonstrated. It is necessary to determine in advance how to install a heat insulation layer in the mold and to conduct thermal conductivity analysis. This is because the degree of heat transfer varies depending on the installation method of the heat insulation layer. However, the degree to which the heat insulation layer is specifically determined in a metal mold | die can be decided suitably according to the requested | required precision etc.

Hereinafter, arrangement | positioning of a heat insulation layer, etc. are demonstrated more concretely.

For example, the metal mold | die in which the heat insulation layer is formed in the whole surface of a cavity is mentioned, FIG. 1 (a) shows the schematic diagram of the cross section of the divided metal mold | die formed in the whole surface of a cavity. Thus, by providing a heat insulation layer in the whole cavity, it can shape | mold so that the surface layer may not be formed in the whole surface of a molded article. As shown in FIG. 1, the split metal mold includes the fixed mold and the movable mold.

When it is determined that the thermal conductivity analysis is performed using a mold as shown in FIG. 1 (a), the thickness L _S (the direction perpendicular to the plane where the split molds are joined) and the thickness L _{M in} the thickness direction of the heat insulation layer are determined. The thickness L _P of the cavity in the thickness direction of the heat insulating layer is determined. These values are also input at the time of thermal conduction analysis. 2 shows the positions of L _S , L _M , and L _P.

In Fig.1 (a), although the heat insulation layer is formed in the whole surface of a cavity, as shown in FIG.1 (b), a heat insulation layer may be formed in a part of cavity surface.

As another example, the metal mold | die in which the metal layer was formed on the heat insulation layer of the metal mold | die in which the heat insulation layer is formed in the whole surface of the said cavity is mentioned, FIG. 1 (c) shows the schematic diagram of the cross section of the division metal mold | die in which the metal layer was formed on such a heat insulation layer.

By forming the metal layer on the heat insulating layer, the wear resistance of the cavity surface is improved. In particular, when an inorganic filler such as glass fiber is blended, the surface of the cavity tends to be worn. Therefore, when using the resin composition which mix | blended glass fiber etc., it is preferable to use the metal mold | die as shown in FIG.1 (c).

When a metal layer exists in the whole surface of a cavity, since the thermal conductivity of a metal layer is high, the need of thickening a heat insulation layer arises.

When it is determined that the thermal conductivity analysis is performed using the mold shown in Fig. 1 (c), the thickness L _S (the direction perpendicular to the plane where the divided molds are joined) and the thickness L _{M in} the thickness direction of the heat insulation layer are determined. The thickness L _P of the cavity in the thickness direction of the heat insulating layer and the thickness L _HI of the metal layer in the thickness direction of the heat insulating layer are determined. These values are input at the time of thermal conduction analysis.

Thermal conduction analysis is performed using input conditions such as the parameters determined as described above. While changing the molding conditions such as the mold temperature, the relationship between the temperature near the cavity surface and the holding time is derived for each molding condition. Then, the molding is actually performed for each molding condition to confirm whether or not a surface layer is formed on the skin layer. For example, the relationship for each molding condition is derived by a graph as shown in FIG. 3 (P ₁ to P _{4 in} FIG. ₃ ). And heat conduction analysis is performed on the conditions which do not have a heat insulation layer of the mold temperature of about 200 degreeC which is a condition that a surface layer is not formed in the surface of a molded article, and the relationship between the temperature near the said mold surface and the said holding time is derived (FIG. 3). Straight line (Q)). Here, in P ₂ , it is assumed that the surface layer is not formed on the surface of the molded article, but the surface layer is formed on the surface of the molded article in P ₃ . The solid line (P ₂₎ and the intersection of the solid line (Q) (α _2), the solid line (P ₃₎ and the solid line threshold or not between the intersection (α ₂₎ of the (Q), that the surface layer is formed on the surface of the molded article (threshold) Is present. For example, it can be determined that there is a threshold at α between α ₂ and α ₃ .

Assuming that the position of α is a threshold value, the temperature range of the temperature in the vicinity of the surface of the mold where the surface layer is not formed on the skin layer of the molded article is equal to or higher than T ° C., and the holding time range of the holding time is t seconds or more. .

In the case where it is impossible to obtain a condition in which the surface layer is not formed on the surface of the molded article by thermal conductivity analysis, the input conditions such as thickening the heat insulating layer or changing the material are changed. In addition, when only the conditions under which the surface layer is not formed on the surface of the molded article can be obtained, the threshold value can be arbitrarily determined among the conditions.

<Second process>

In a 2nd process, a heat insulation layer is provided in a metal mold | die so that a surface layer may not be formed on the skin layer of a molded article. The material, shape, and place of the heat insulation layer may be used for the heat conduction analysis of the first step, but the molding conditions are examined to satisfy the above temperature range and the holding time range using the heat conduction analysis for the other heat insulation layer. can do. In the examination, as described above, the material, the position, and the like of the heat insulating layer are input, and the parameters of specific gravity, specific heat, thermal conductivity, and thermal diffusivity of the material constituting the mold are input, and each of the plurality of molding conditions is located near the cavity surface. The relationship between the temperature of the resin and the holding time is derived.

If the molding conditions satisfy the temperature range and the holding time range, no surface layer is formed on the surface of the molded article. That is, what is necessary is just to form the heat insulation layer similar to the information of the input heat insulation layer in a metal mold | die.

<Heat insulation layer>

Here, before explaining the formation method of a heat insulation layer, the heat insulation layer etc. which are easy to satisfy the said temperature range and holding time range are demonstrated briefly.

It is preferable that a heat conductivity is 0.3 W / m * K or less, and 60 micrometers or more of thickness are heat conductivity. If it is a heat insulating layer which satisfy | fills these conditions, it exists in the tendency which can insulate enough, and it is easy to satisfy the said temperature range and holding time range.

Epoxy, polyimide, polybenzoimidazole, polyimide, and polyether ether ketone are examples of materials having a thermal conductivity of 0.3 W / m · K or less and at the same time having heat resistance that can withstand high temperatures during molding. Can be.

As mentioned above, a metal layer can be arrange | positioned on a heat insulation layer. As a metal layer, plates, such as aluminum and SUS, are used preferably. As a method of forming a metal layer on a heat insulation layer, a conventionally well-known lamination method etc. can be employ | adopted. Although the thickness of a metal layer is based also on the kind of metal contained in a metal layer, it is preferable that it is 0.1 mm or less. In addition, when using a metal plate as mentioned above, as mentioned above, it is necessary to thicken a heat insulation layer, For example, it sets to 10 mm or more, More preferably, it is set to 20 mm or more.

In addition, a thin film-like metal layer can be formed on the heat insulating layer by using a conventionally known plating film forming method such as sputtering or ion plating. Since the plated film is very thin, unlike the case of using a metal plate, the thickness of the heat insulating layer is preferably 60 µm or more.

The method of forming the heat insulating layer on the inner surface of the metal part of the mold is not particularly limited. For example, it is preferable to form a heat insulation layer on the inner surface of a metal mold by the following method.

A solution of a polymer precursor such as a polyimide precursor capable of forming a polymer heat insulating layer is applied to the inner surface of the metal part of the mold, heated to evaporate the solvent, and further heated to polymerize to form a heat insulating layer such as a polyimide film. A method, a method of depositing and polymerizing a monomer of a heat-resistant polymer such as pyromellitic anhydride and 4,4-diaminodiphenyl ether, and preparing a piece mold in which a portion corresponding to the surface of the cavity is made of an insulating plate The method of mounting a mold to a main mold is mentioned. Or with respect to a planar metal mold | die, the suitable adhesive method using a polymer heat insulation film, or the method of sticking to the desired part of a metal mold | die using the polymer heat insulation film of an adhesive tape form, and forming a heat insulation layer are mentioned. In addition, formation of a heat insulation layer may be a method of electrodepositing resin which forms a heat insulation layer to a metal mold | die. A metal layer can be formed for the purpose of providing durability, such as flaw prevention of a heat insulation layer and a heat insulation board surface.

In addition, a ceramic material can be used as a heat insulation layer. Since the surface of the ceramic material is excellent in wear resistance, it is not necessary to arrange the above metal layer on the heat insulating layer made of the ceramic material. As a ceramic material, use of porous zirconia, silicon dioxide, etc. which contain a bubble inside is preferable. Especially, since the heat insulation layer which consists of porous zirconia is mainly comprised by zirconia, it is high in durability to the pressure applied to a heat insulation layer at the time of injection molding. Therefore, the fault of the heat insulation layer caused by the pressure is not easily generated. For this reason, the frequency | count which interrupts shaping | molding in the middle of injection molding decreases, and productivity of an injection molded article increases.

It does not specifically limit as zirconia, Any of stabilized zirconia, partially stabilized zirconia, and unstable zirconia can be used. Stabilized zirconia is cubic zirconia stabilized even at room temperature, and is excellent in mechanical properties such as strength and toughness and wear resistance. Partially stabilized zirconia refers to a state in which tetragonal zirconia remains at room temperature, and when an external stress is applied, martensite transformation occurs from tetragonal to monoclinic, particularly tensile stress. By the action of inhibits the growth of cracks and has high fracture toughness. In addition, unstabilized zirconia refers to zirconia that is not stabilized with a stabilizer. At least two or more types selected from stabilized zirconia, partially stabilized zirconia, and unstabilized zirconia may be used in combination.

As a stabilizer contained in stabilized zirconia and partially stabilized zirconia, a conventionally well-known general thing can be employ | adopted. For example, yttria, ceria, magnesia, etc. are mentioned. The amount of the stabilizer to be used is also not particularly limited, and the amount of the stabilizer can be appropriately set depending on the use, the material used and the like.

In addition, in the range that does not impair the effects of the present invention, in addition to the zirconia, stabilizer may include a conventionally known additives.

Although the method of forming a heat insulation layer using the said raw material is not specifically limited, It is preferable to employ the thermal spraying method. By employing the thermal spraying method, the thermal conductivity of the porous zirconia can be easily adjusted to a desired range. In addition, problems such as a large decrease in the mechanical strength of the heat insulating layer due to excessive bubbles are formed inside the porous zirconia. By forming the heat insulation layer by thermal spraying in this way, the structure of a heat insulation layer becomes a thing suitable for the use of this invention.

Formation of the heat insulation layer by thermal spraying can be performed as follows, for example. First, the raw material of the heat insulation layer is melted and made into a liquid. This liquid is accelerated to impinge on the inner surface of the cavity. Finally, the raw materials that collide with the inner surface of the cavity are solidified. In this way, a very thin heat insulating layer is formed on the inner surface of the mold. Thus, the thickness of a heat insulation layer can be adjusted by further colliding and solidifying the raw material melted on the very thin heat insulation layer. The method of solidifying a raw material can use a conventionally well-known cooling means, and can also solidify only by leaving it to stand. The spraying method is not particularly limited, and preferable methods can be suitably selected in the conventionally known methods such as arc spraying, plasma spraying, and frame spraying.

The heat insulation layer which has said multilayer structure can be manufactured by adjusting the manufacturing conditions of a heat insulation layer. For example, when forming a heat insulation layer by a thermal spraying method, it can manufacture by adjusting the conditions etc. which adhere the melted raw material to the metal mold | die inner surface.

[Example]

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples.

&Lt; Example 1 &gt;

In Example 1, the following materials were used.

Resin: Liquid crystalline resin (Polyplastics, Inc., "Vectra E463i")

Heat insulation layer: After spraying polyimide resin (polyimide resin varnish (Fine Chemical Japan Co.)) and thermal conductivity 0.2W / m * K to the inner surface of a metal mold | die, and heat-processing at 250 degreeC for 1 hour, a polyimide surface is Polished.)

In addition, the metal mold | die shown in FIG. 4 was used. The thickness of such a heat insulating layer _{is, L M = 10mm, L P} = 0.7mm, was L _S = 0.06mm.

Specific gravity, specific heat, thermal conductivity, and thermal diffusivity of the material constituting the mold and the liquid crystalline resin are as shown in Table 1 below. The thermal conductivity was calculated by measuring the thermal diffusivity by the laser flash method. Specific gravity was measured by the Archimedes method, and specific heat was measured by DSC.

Using Therm 1 (one-dimensional thermal conductivity analysis software), the relationship between the temperature of the resin at a depth of 7 μm from the cavity surface and the holding time of the resin in the mold is determined by molding conditions such as the mold temperature shown in Table 2. Derived. The derived relationship is graphed and shown in FIG. 5. 5 is the same as that of Example 1 except having not provided a heat insulation layer, and the result of the heat conduction analysis of the conditions of the mold temperature of 200 degreeC was also shown.

In addition, a molded article was produced under the molding conditions shown in Table 2, and the presence or absence of the surface layer was confirmed by attaching a cello tape (registered trademark) to the molded product and peeling the cello tape (registered trademark). Table 2 also shows the presence or absence of the surface layer.

There is a threshold value indicating whether or not a surface layer is formed between the intersections of the graph indicating the above relationship under the condition of the heat insulating layer and the mold temperature of 200 캜 and the graph indicating the above relationship in the molding conditions 2 and 3. And from FIG. 5, when the resin which flowed into the metal mold | die maintains the state 230 degreeC or more for 0.3 second or more, it can be estimated that a surface layer is not formed on a skin layer.

That is, the heat insulation layer which keeps a 230 degreeC or more state for 0.3 second or more is determined by heat conduction analysis, and this heat insulation layer is installed in a metal mold | die, and the metal mold | die for shaping | molding is manufactured. In this way, when a mold is manufactured and molded under specific molding conditions (for example, the molding condition 3 described above), a molded article having no surface layer formed on the skin layer can be injection molded.

<Example 2>

In Example 2, the following materials were used.

Resin: Liquid crystalline resin (Polyplastics, Inc., "Vectra E463i")

Insulation layer: Insulation plate made of glass fiber and silicic acid binder

Metal layer 1: SUS plate

Metal layer 2: Aluminum plate

In addition, the metal mold | die shown in FIG. 6 was used. The thickness of such a heat insulating layer is, was set to _{L M = 10mm, L P =} 0.7mm, L S = 10mm, 20mm, or _{30mm, L HI = 0.05mm, 0.10mm} , 0.15mm, 0.20mm or 0.25mm.

Specific gravity, specific heat, thermal conductivity, and thermal diffusivity of the material constituting the mold and the liquid crystalline resin are as shown in Table 3 below.

The thermal conductivity analysis was performed similarly to the molding condition 3 of Example 1, and the relationship between the temperature of resin in the depth of 7 micrometers, and the holding time of the resin in the metal mold | die was derived from the cavity surface. Resin which flowed into the metal mold | die was evaluated as "(circle)" to hold | maintain a 230 degreeC or more state for 0.3 second or more, and the other thing was evaluated as "x". The evaluation results are shown in Tables 4 and 5 for the conditions of the thickness of the heat insulating layer and the thickness of the metal layer.

As is clear from the results of Example 2, it was confirmed that even when a metal layer was formed on the heat insulating layer, a molded article having no surface layer formed on the surface thereof could be produced. In addition, it was confirmed that the thickness of the allowable metal layer depends on the type of metal. However, when the thickness of the metal layer was about 1 mm or less, it was confirmed that the insulating layer was not easily formed on the surface of the molded article. Moreover, it was confirmed that if the thickness of a heat insulation board is 20 mm or more, it will be easy to become a heat insulation layer in which the surface layer is not formed in the surface of a molded article.

As mentioned above, even if a metal layer is formed on a heat insulation layer, similarly to Example 1, the heat insulation layer which hold | maintains 230 degreeC or more state for 0.3 second or more is determined by heat conduction analysis, and this heat insulation layer is installed in a metal mold | die, and a metal mold | die for shaping | molding is manufactured. do. By shaping | molding using the metal mold | die manufactured in this way, the molded article which does not form a surface layer on a skin layer can be injection-molded.

<Example 3>

In Example 3, the following materials were used.

Resin: Liquid crystalline resin (Polyplastics, Inc., "Vectra E463i")

Insulation layer: Zirconia sprayed porous zirconia layer

As a result of Example 1, in the case of the molding condition 3 of Example 1, it was estimated that the surface layer was not formed on the skin layer by maintaining the state in which the resin which flowed into the metal mold | die was 230 degreeC or more for 0.3 second or more.

In Example 3, the thickness of the heat insulation layer in which resin which flowed into the metal mold | die hold | maintains 230 degreeC or more state for 0.3 second or more when the heat insulation layer is made into a porous zirconia layer is used using Therm 1 (one-dimensional heat conduction analysis software). Derived. As the metal mold | die, the metal mold | die shown in FIG. 4 similar to Example 1 was assumed. That is, L _M = 10 mm and L _P = 0.7 mm. Specific values, specific heat, thermal conductivity, and thermal diffusivity of the materials constituting the mold and the liquid crystalline resin used the values shown in Table 6 below.

Using Therm 1 (one-dimensional thermal conductivity analysis software), the relationship between the temperature of the resin at a depth of 7 μm from the cavity surface and the holding time of the resin in the mold is performed for each thickness by changing the thickness of the heat insulating layer. When it derived similarly to Example 1, when the thickness of a heat insulation layer was 500 micrometers, it was estimated that resin which flowed into the metal mold | die keeps 230 degreeC or more state for 0.3 second or more in the case of the molding condition 3 of Example 1. Thus, the mold shown in Fig. 4 was actually fabricated with L _M = 10 mm, L _P = 0.7 mm, and L _S = 500 µm. The formation method of a heat insulation layer is mentioned later.

Moreover, the molded article was produced on the molding conditions shown in Table 7, and the presence or absence of the surface layer was confirmed by attaching a cello tape (registered trademark) to the molded article and peeling the cello tape (registered trademark). Table 7 also shows the presence or absence of the surface layer.

Specific molding conditions are set, and the thickness of the heat insulation layer which maintains a 230 degreeC or more state for 0.3 second or more is determined by heat conduction analysis, and the heat insulation layer of this thickness is installed in a metal mold | die, and the metal mold | die for shaping | molding is manufactured. In this way, when a mold is manufactured and molded under the set molding conditions (for example, the molding conditions 3 described above), a molded article having no surface layer formed on the skin layer can be injection molded.

<Formation of Insulation Layer and Measurement of Physical Properties>

The formation method of the said heat insulation layer and the measuring method of the physical property of the heat insulation layer shown in Table 1 are demonstrated. The raw material mainly comprised of zirconia was sprayed on the inner surface of the said metal mold by the thermal spraying method. The surface of the heat insulation layer was adjusted so that a density might become high, and the heat insulation layer of a multilayer structure was formed in the metal mold | die inner surface. Thermal spraying was continued until the thickness of the heat insulation layer became 500 micrometers.

The thermal conductivity was calculated by measuring the thermal diffusivity by the laser flash method. Specific gravity was measured by the Archimedes method, and specific heat was measured by DSC.

The thermal conductivity of the zirconia insulation layer is measured by specific heat by the thermal diffusivity and DSC by the laser flash method, and by specific gravity by the submerged method (according to JIS Z8807 solid specific gravity measurement method). Calculated. The thermal conductivity (λ) of the heat insulating layer having a multilayer structure is obtained from the thermal conductivity of each of the low density layer and the high layer, and the thermal conductivity (λl) of the low density layer, the thermal conductivity of the high density layer (λh), and the density of the entire thickness of the thermal insulation layer. If it is the thickness ratio (t) of the lower layer,

It calculated | required by calculation using the formula of [1 / (lambda)] = [t / (lambda) l] + [(1-t) / (lambda) h].

As a result of actual measurement, specific gravity, specific heat, thermal conductivity, and thermal diffusivity of the material constituting the mold and the liquid crystalline resin were as shown in Table 6 above.

Claims (7)

In the manufacturing method of the metal mold | die for manufacturing the molded article which consists of liquid crystalline resin composition containing liquid crystalline resin,
By deriving the relationship between the temperature near the mold surface of the liquid crystalline resin filled in the mold and the holding time of the liquid crystalline resin in the mold, the surface layer is not formed on the skin layer of the molded article. Deriving a temperature range of the temperature and a holding time range of the holding time to install a heat insulating layer satisfying the temperature range and the holding time range,
The said thermal conductivity analysis uses the metal mold | die with which the heat insulation layer was formed in the surface of a cavity, and uses the specific gravity, specific heat, heat conductivity, and thermal diffusivity of the material and the liquid crystalline resin which make up a metal mold | die as a parameter. The method of claim 1,
The temperature range is 230 ℃ or more,
Method of manufacturing a mold wherein the holding time range is 0.3 seconds or more. 3. The method according to claim 1 or 2,
The method of manufacturing a mold wherein the thermal conductivity analysis determines the material, installation position, and shape of the range heat insulating layer. The method according to any one of claims 1 to 3,
The thermal insulation layer has a thermal conductivity of 0.3 W / m? Hereinafter, the manufacturing method of the metal mold | die whose thickness is 60 micrometers or more. The method according to any one of claims 1 to 4,
The said heat insulation layer is a manufacturing method of the metal mold | die which contains at least 1 sort (s) of resin chosen from polybenzoimidazole, polyimide, and polyether ether ketone. The method according to any one of claims 1 to 4,
The said heat insulation layer is a manufacturing method of the metal mold | die which is a ceramic material comprised from porous zirconia. 6. The method according to any one of claims 1 to 5,
The said heat insulation layer is a manufacturing method of the metal mold | die which has a metal layer on the surface.

Images