KR20120111943A - Method for producing injection-molded article - Google Patents

Abstract

In the case of ultrasonic cleaning of the liquid crystalline resin composition, it is possible to suppress the fibrillation of the surface of the injection molded article and to provide a molding technique for obtaining a molded article having an excellent appearance. In particular, the shaping | molding technique which can be implemented also in the conditions whose mold temperature is 100 degrees C or less is provided. In the injection molding of the liquid crystalline resin composition, using a mold having a heat insulating layer formed on the mold inner surface, the thickness of the heat insulating layer is t1 (µm), the injection speed is S (mm / sec), and the thickness of the injection molded product is t2 (mm). In the case where the mold temperature is T (° C), injection molding is performed under molding conditions satisfying a specific relational expression. Preferably, molding is performed at a mold temperature of 100 ° C. or lower.

Description

Manufacturing method of injection molded article {METHOD FOR PRODUCING INJECTION-MOLDED ARTICLE}

The present invention relates to a method for producing an injection molded article using the liquid crystalline resin composition.

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-described high strength and excellent 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 usually ultrasonically cleaned using water and the like, and small garbage, oil, dust, etc. attached to the surface of the components are removed. However, the molded article formed by molding the liquid crystalline resin composition has a relatively large molecular orientation in the surface portion, so that the surface is relatively fibrillated. For this reason, if the surface of a molded article peels off, it will become a factor of the falling-out thing (garbage). Therefore, since generation | occurrence | production of a waste etc. becomes a problem, it is very difficult to ultrasonically wash the molded article formed by shape | molding a liquid crystalline resin composition.

The generation of garbage and the like occurs because the molecular orientation is particularly large on the surface of the molded article as described above. Thus, a resin molded article containing a liquid crystalline polymer and a fibrous filler as a resin molded article having improved surface characteristics, characterized by having a flat portion having a rising width of the surface roughness Ra value of 0.4 µm or less required by a specific surface tape peeling test. A resin molded article is disclosed (Patent Document 1: Japanese Unexamined Patent Publication No. 2008-239950).

According to the method of patent document 1, it is useful as a component of an electrical / electronic device or an optical device, and it is said that generation | occurrence | production of surface particle (foreign material) can be prevented. Thus, using the technique of patent document 1, the surface characteristic 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 generate | occur | produces when the surface is wash | cleaned by stirring for 1 minute slowly in pure water. Therefore, with the improvement of the surface characteristic by the method of patent document 1, the result which is satisfactory about suppression of the fibrillation at the time of ultrasonic cleaning cannot be obtained. That is, according to the method of the said patent document 1, when exposing a resin molded article to severe conditions, such as ultrasonic cleaning, very many foreign substances generate | occur | produce.

Moreover, in patent document 1, in order to suppress generation | occurrence | production of the said garbage etc., it is said that it is preferable that the metal mold temperature at the time of shaping | molding is high. In fact, in the Example of patent document 1, shaping | molding is performed on condition of 130 degreeC of die temperature. If the mold temperature is set to a temperature higher than 100 ° C, the temperature cannot be adjusted by water and the temperature must be adjusted by oil. For this reason, it is required to shape | mold mold temperature on condition of 100 degrees C or less from a viewpoint of making production of an injection molded product easy.

In addition, the injection molded article is particularly susceptible to surface fibrillation because molecular orientation is large at the surface portion, and is liable to fluff when ultrasonic cleaning is performed. For this reason, the surface characteristic improvement technique applicable to injection molded articles is calculated | required.

In addition, fluffing of the surface, such as peeling of the surface of the molded article, damages the appearance of the injection molded article. For this reason, the injection molded article formed by injection molding a liquid crystalline resin composition is also required to have the outstanding external appearance.

1. Japanese Unexamined Patent Publication No. 2008-239950

The present invention has been made to solve the above problems, and its object is to provide a molding technique for obtaining a molded article having an excellent appearance by suppressing fibrillation of the surface of an injection molded article even when ultrasonically cleaning the liquid crystalline resin composition. It is. In particular, it is providing the molding technique which can be implemented also in the conditions of 100 degrees C or less of die temperature.

MEANS TO SOLVE THE PROBLEM The present inventors earnestly researched in order to solve the said subject. As a result, in the injection molding of the liquid crystalline resin composition, when using a mold having a heat insulating layer formed on the surface of the mold, the thickness of the heat insulating layer is t1, the injection speed is S, the thickness of the injection molded product is t2 and the mold temperature is T. It has been found that the above problems can be solved by injection molding under molding conditions satisfying a specific relational expression, and the present invention has been completed. Specifically, the present invention provides the following.

 (1) In the injection molding of the liquid crystalline resin composition, using a mold having a heat insulating layer formed on the surface of the mold, the thickness of the heat insulating layer is t1 (µm), the injection speed is S (mm / sec), and the thickness of the injection molded article is t2 ( mm) and a method for producing an injection-molded article subjected to injection molding under molding conditions satisfying the following formula (I) when the mold temperature is T (° C).

[Equation 1]

1000 ??? (Ⅰ)(t1 × S) / t2 + T

1000 ??? (Ⅰ)

 (2) The method for producing an injection molded article according to (1), which is injection molded under molding conditions satisfying the following formula (II).

&Quot; (2) "

2000 ??? (II)(t1 × S) / t2 + T

2000 ??? (II)

(3) The manufacturing method of the injection molded article as described in (1) or (2) whose thermal conductivity of the said heat insulation layer is 5 W / m * K or less.

 (4) The method for producing an injection molded article according to any one of (1) to (3), wherein the heat insulation layer contains a polyimide resin.

(5) The manufacturing method of the injection molded article in any one of (1)-(4) whose mold temperature T is 100 degrees C or less.

The injection-molded article obtained by the production method of the present invention does not generate a dropping material (garbage) due to peeling of the surface of the molded article even when ultrasonically cleaned. For this reason, the injection molded article used for the precision instrument, the optical instrument, etc. manufactured by the manufacturing method of this invention can perform ultrasonic cleaning easily, and can perform the cleaning operation | work at the time of component manufacture efficiently.

The injection molded article obtained by the production method of the present invention has an excellent appearance. In particular, since the surface of the injection molded article obtained by the manufacturing method of the present invention is not easily peeled off, it is easy to maintain a beautiful appearance for a long time.

The manufacturing method of this invention can be implemented on the conditions of 100 degrees C or less of die temperature. For this reason, the temperature control of the metal mold | die at the time of obtaining an injection molded article can be performed with water instead of oil. As a result, an excellent injection molded article can be easily obtained.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the multilayered structure of the injection molded article obtained by the manufacturing method of this invention.
Fig. 2 is a diagram showing a multilayer structure of an injection molded article obtained by the manufacturing method of the prior art.
3 is a diagram showing a multilayer structure of an injection molded article manufactured under conditions satisfying the following formula (II).

EMBODIMENT OF THE INVENTION Hereinafter, although one Embodiment of this invention is described in detail, this invention is not limited to the following embodiment, It can implement by changing suitably within the range which this invention aims at.

The present invention is to use a mold having a heat insulating layer formed on the surface of the mold in the injection molding of the liquid crystalline resin composition, the thickness of the heat insulating layer t1 (㎛), the injection speed S (mm / sec), the thickness of the injection molded product t2 (mm), and when the mold temperature is T (° C), injection molding is carried out under molding conditions satisfying a specific relational expression. Hereinafter, this invention is demonstrated in order of the manufacturing method of a liquid crystalline resin composition and an injection molded article.

<Liquid crystalline resin composition>

The manufacturing method of the injection molded article of this invention is applicable to all the liquid crystalline resin compositions containing liquid crystalline resin.

The liquid crystalline resin refers to a melt processable polymer having a property capable of forming an optically anisotropic molten phase. The property of the anisotropic molten phase can be confirmed by the conventional polarization test method using a rectangular polarizer. More specifically, the anisotropic molten phase can be confirmed by observing a molten sample placed on a Leitz hot stage using a Leitz polarizing microscope at a magnification of 40 times under a nitrogen atmosphere. When the liquid crystalline resin applicable to this invention is examined between orthogonal polarizers, even if it is a melting stop state, polarization will normally transmit and show optically anisotropy.

Although it does not specifically limit as said liquid crystalline resin, It is preferable that they are aromatic polyester or aromatic polyester amide, and the polyester which partially contains aromatic polyester or aromatic polyester amide in the same molecular chain is also in the range. . They are preferably those having a logarithmic viscosity (I.V.) of at least about 2.0 dl / g, more preferably 2.0 to 10.0 dl / g when dissolved in pentafluorophenol at a concentration of 0.1 wt% at 60 ° C.

As the aromatic polyester or the aromatic polyester amide of the liquid crystalline resin applicable to the present invention, particularly preferably, at least one compound selected from the group consisting of aromatic hydroxy carboxylic acid, aromatic hydroxy amine and aromatic diamine Aromatic polyester and aromatic polyester amides.

More specifically,

(1) Polyester mainly consisting of 1 type, or 2 or more types of aromatic hydroxy carboxylic acid and its derivative (s);

(2) mainly (a) one or two or more of aromatic hydroxy carboxylic acids and derivatives thereof, (b) one or two or more of aromatic dicarboxylic acids, alicyclic dicarboxylic acids and derivatives thereof, And (c) polyesters comprising at least one or two or more of aromatic diols, alicyclic diols, aliphatic diols and derivatives thereof;

(3) mainly one or two or more of (a) aromatic hydroxy carboxylic acids and derivatives thereof, (b) one or two or more of aromatic hydroxy amines, aromatic diamines and derivatives thereof, and (c) aromatics Polyesteramides composed of one kind or two or more kinds of dicarboxylic acids, alicyclic dicarboxylic acids, and derivatives thereof; And

(4) mainly (a) one or two or more of aromatic hydroxy carboxylic acids and derivatives thereof, (b) one or two or more of aromatic hydroxy amines, aromatic diamines and derivatives thereof, and (c) aromatic dicha Polyesteramides composed of one or two or more kinds of carboxylic acids, alicyclic dicarboxylic acids and derivatives thereof, and (d) at least one or two or more kinds of aromatic diols, alicyclic diols, aliphatic diols and derivatives thereof. Etc. can be mentioned. And a molecular weight modifier can be used together to said structural component as needed.

Preferred examples of the specific compound constituting the liquid crystalline resin applicable to the present invention include aromatic hydroxy carboxylic acids such as p-hydroxy benzoic acid and 6-hydroxy-2-naphthoic acid, and 2,6-di. Aromatics such as hydroxy naphthalene, 1,4-dihydroxy naphthalene, 4,4'-dihydroxybiphenyl, hydroquinone, resorcin, compounds represented by the following general formula (A) and the following general formula (B) Diols; Aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 4,4'-diphenyl dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, and a compound represented by the following general formula (C); And aromatic amines such as p-amino phenol and p-phenylene diamine.

[Formula 1]

(X: a group selected from alkylene (C1 to C4), alkylidene, -O-, -SO-, -SO _2- , -S-, -CO-.)

[Formula 2]

(3)

(Y:-(CH ₂ ) _n- (n = 1 to 4), -O (CH ₂ ) _n O- (n = 1 to 4) is a group selected.)

 [Other Ingredients]

In the liquid crystalline resin composition used in the present invention, pigments such as other resins, nucleating agents, carbon blacks, and inorganic plastic pigments, antioxidants, stabilizers, plasticizers, lubricants, mold release agents and flame retardants within a range that does not impair the effects of the present invention. The composition which added the additive and provided the desired characteristic is also contained in the liquid crystalline resin composition used for this invention.

<Production method of injection molded article>

In the method for producing an injection molded article of the present invention, in the injection molding of the liquid crystalline resin composition, using a mold having a heat insulating layer formed on the surface of the mold, the thickness of the heat insulating layer is t1 (μm), the injection speed is S (mm / sec), When the thickness of the injection-molded product is t2 (mm) and the mold temperature is T (° C), injection molding is performed under molding conditions satisfying the relational expression of the following formula (I).

&Quot; (3) &quot;

1000 ??? (Ⅰ)
(t1 × S) / t2 + T

1000 ??? (Ⅰ)

[mold]

In the manufacturing method of the injection molded article of this invention, the metal mold | die with which the heat insulation layer was formed in the inner surface (inner surface of a metal mold) of a metal mold | die is used. The liquid crystal resin composition flowing into the mold due to the heat insulating layer formed on the inner surface of the mold becomes difficult to harden near the mold surface. As a result, the molecule | numerator contained in the resin composition before solidification which contacts the resin composition solidified on the mold surface can be attracted by the resin composition after the solidification, and it can suppress that molecular orientation becomes large on the molded article surface.

If the heat insulation layer formed in the inner surface of a metal mold | die has a function which slows solidification of the liquid crystalline resin composition on a metal mold | die surface, a material etc. are not specifically limited. Moreover, the thing in which a heat insulation layer is formed in a part of mold inner surface is also included in the "mold with a heat insulation layer formed in the mold inner surface." In the manufacturing method of the injection molded article of this invention, it is necessary to form in the whole mold inner surface part corresponding to the part where the favorable external appearance characteristic is calculated | required at least in the obtained molded object, and it is preferable to form in the whole mold inner surface. The thickness t1 of the heat insulation layer is not particularly limited as long as the thickness t1 is adjusted to satisfy the above formula (I). The thickness of the heat insulation layer formed on the inner surface of the mold may be uniform, and may include locations having different thicknesses. When thickness of a heat insulation layer is not uniform, let average thickness be t1.

Moreover, it is especially preferable that the thermal conductivity of the heat insulation layer formed in the metal mold | die inner surface is 5 W / m * K or less. By adjusting the thermal conductivity of the heat insulating layer in the above range, even when the injection molded article is molded at a mold temperature of 100 ° C. or less, it is possible to more easily obtain an injection molded article having excellent appearance without peeling off the surface of the molded article when ultrasonic cleaning or the like is performed. The said thermal conductivity shows the thermal conductivity measured by the method as described in an Example.

In addition, since a high temperature liquid crystalline resin composition flows into the mold during injection molding, the heat insulating layer needs to have heat resistance that can withstand high temperatures during molding.

It is preferable that the heat insulation layer formed in the inner surface of the metal mold | die used for the manufacturing method of the injection molded article of this invention contains a polyimide resin. This is because the polyimide resin has a heat conductivity of 5 W / m · K or less and has heat resistance sufficiently resistant to high temperatures during injection molding. Specific examples of the polyimide resin that can be used include pyromellitic acid (PMDA) polyimide, biphenyl tetracarboxylic acid polyimide, polyamideimide using trimellitic acid, and bismaleimide resin (bis maleimide / triazine series). Etc.), a benzophenone tetracarboxylic acid polyimide, an acetylene terminal polyimide, a thermoplastic polyimide, etc. are mentioned. Here, it is especially preferable that it is a heat insulation layer which consists of polyimide resin. As preferable materials other than polyimide resin, tetrafluoro ethylene resin etc. are mentioned, for example.

The method of forming a heat insulation layer in the inner surface of a metal mold | die is not specifically limited. For example, it is preferable to form a heat insulation layer in the inner surface of a metal mold by the following method.

A method of forming a heat insulating layer such as a polyimide membrane by applying a polymer precursor solution such as a polyimide precursor capable of forming a polymer heat insulating layer to the surface of a mold, heating to evaporate the solvent, and further heating to polymerize, a monomer of a heat resistant polymer For example, the method of vapor-polymerizing pyromellitic anhydride and 4,4-diamino diphenyl ether, or the planar metal mold | die, using a polymer heat insulation film using the suitable adhesive method or the adhesive tape-shaped polymer heat insulation film The method of sticking to the desired part of a metal mold | die, and forming a heat insulation layer is mentioned. In addition, a polyimide film can be formed, and a chromium (Cr) film or a titanium nitride (TiN) film can be further formed on the surface thereof as a metallic hard film.

[Molding conditions]

In the method for producing an injection molded article of the present invention, when the thickness of the heat insulating layer is t1 (µm), the injection speed is S (mm / sec), the thickness of the injection molded article is t2 (mm), and the mold temperature is T (° C). It is characterized by performing injection molding under molding conditions satisfying the relational expression of the following formula (I).

&Quot; (4) &quot;

1000 ??? (Ⅰ)(t1 × S) / t2 + T

1000 ??? (Ⅰ)

By manufacturing the injection molded article under the conditions described above, in the injection molded article obtained, the boundary between the surface layer and the skin layer is not present on at least a part of the surface of the molded article. The peeling of the surface of the injection molded product is caused by the peeling of the surface layer formed on top of the skin layer, but in the present invention, an injection molded article having no such surface layer is obtained on at least a part of the surface of the molded product. As a result, it is possible to obtain a high-quality injection molded article having excellent appearance and without peeling off the surface even when ultrasonically cleaned.

The injection molded article obtained by the production method of the present invention is characterized by removing at least part of the boundary between the surface layer and the skin layer on the surface of the molded article. As a result of obtaining such an injection molded article, the effect of suppressing the peeling of the surface of the injection molded article is significantly increased. The injection molded article having a very low peeling on the surface of the molded article and having an excellent appearance prevents the liquid crystal resin composition flowing into the mold from solidifying immediately on the mold surface, and the molecules of the resin composition portion before solidification are attracted by the solidified resin composition. It is assumed that it is obtained by suppressing increase in molecular orientation on the surface of the molded article.

As mentioned above, when the liquid crystalline resin composition in a molten state flowed into a metal mold | die, as mentioned above, it has a function which suppresses that a resin composition hardens immediately in the metal mold surface.

By improving the injection speed, the time for filling the mold with the resin composition is shortened. That is, the filling of the liquid crystalline resin composition into the mold can be finished at the stage where the solidification of the liquid crystalline resin composition does not proceed too much. As a result, the molecule | numerator of the part before solidification is attracted by the solidified resin composition, and it can suppress that molecular orientation becomes large on the molded article surface.

If the thickness of the injection molded article is too thick, it takes time to fill the liquid crystalline resin composition into the mold. For this reason, when the thickness of an injection molded article is too thick, the phenomenon of molecular orientation becoming large on the surface of a molded article is likely to be attracted by the molecule | numerator before the solidification by the solidified resin composition.

By setting mold temperature T high, solidification of the liquid crystalline resin composition in the inner surface vicinity of a metal mold | die can be slowed especially. As a result, the phenomenon in which the molecule | numerator of the part before solidification is attracted by the solidified resin composition, and molecular orientation becomes large on the surface of a molded article can be suppressed.

A feature of the present invention is that the injection molded article is adjusted by adjusting the thermal insulation layer thickness t1 (µm), the injection speed S (mm / sec), the mold temperature T (° C), and the injection molded article thickness t2 (mm) to satisfy the above formula (I). It is found that the boundary between the surface layer and the skin layer disappears.

In the present invention, an excellent injection molded article having various shapes (especially even when t2 (mm) is thick) is produced by adjusting the injection speed S (mm / sec), the heat insulation layer thickness t1 (µm), and the mold temperature T (° C). can do. This is because if the above formula (I) is satisfied, the boundary between the surface layer and the skin layer of the injection molded article does not exist at least in part.

In addition, by injection molding under molding conditions satisfying the following formula (II), surface peeling is less likely to occur, and an injection molded article having a very excellent appearance can be obtained. Specifically, by performing injection molding on the condition that the following formula (II) is satisfied, a molded article having no boundary between the surface layer and the skin layer can be easily obtained. Hereinafter, the manufacturing conditions of the manufacturing method of this invention are demonstrated in detail.

[Equation 5]

2000 ??? (II)(t1 × S) / t2 + T

2000 ??? (II)

First, heat insulation layer thickness t1 (micrometer) is demonstrated. The heat insulation layer thickness t1 can be adjusted to satisfy said formula (I), and the thickness is not specifically limited. Although it depends on the kind of liquid crystalline resin composition used, the shape of an injection molded article, etc., in the manufacturing method of this invention, it is preferable to adjust the heat insulation layer thickness t1 to 1 micrometer-1000 micrometers. Since sufficient heat insulation effect can be obtained by adjusting the heat insulation layer thickness to 1 micrometer or more, it is preferable to adjust to 1000 micrometers or less from a viewpoint of the precision of a molded article. More preferable heat insulation layer thickness t1 is 10 micrometers-300 micrometers.

Next, the injection speed S (mm / sec) is demonstrated. The injection speed S may also be adjusted to satisfy the formula (I) as in the heat insulating layer thickness t1. Although it depends on the kind of liquid crystalline resin composition used, the shape of an injection molded article, etc., in the manufacturing method of this invention, it is preferable to adjust the injection speed S to the range of 20 mm / sec-1000 mm / sec. It is preferable because the hedging can be prevented by adjusting the injection speed to 20 mm / sec or more, and preferred because jetting can be prevented by adjusting the injection speed to 1000 mm / sec or less. More preferred injection speed is 50 mm / sec to 500 mm / sec.

Next, die temperature T (degreeC) is demonstrated. The mold temperature T may be adjusted to satisfy the formula (I) as in the heat insulating layer thickness t1. Although it depends on the kind of liquid crystalline resin composition used, the shape of an injection molded article, etc., in the manufacturing method of this invention, it is preferable to adjust die temperature T to 100 degrees C or less. By setting the mold temperature T to 100 degrees C or less, temperature control of a metal mold | die can be performed with water, and high quality injection molded article can be obtained easily. The range of more preferable mold temperature is 50 degreeC-100 degreeC.

The injection molded article thickness t2 can be adjusted in a wide range by adjusting the said heat insulation layer thickness t1, the injection speed S, and the metal mold | die temperature T. Specifically, the thickness of the injection molded article t2 may be adjusted to 0.2 mm to 10 mm under conditions satisfying the formula (I). Under conditions satisfying the above formula (II), t2 can be adjusted to 0.2 mm to 5 mm. In particular, in the range of the thickness of the injection molded product (t2) of 0.2mm to 3mm, the above problem is likely to occur, but by molding according to the manufacturing method of the present invention, it is possible to easily obtain a high-quality injection molded product having no excellent surface peeling and excellent appearance. .

[Injection molded article]

When the liquid crystalline resin composition is molded, a multilayer structure is obtained. 1 shows a multilayer structure (from the center portion to the surface portion) of an injection molded article obtained by the production method of the present invention. As shown in Fig. 1 (a), the injection molded article obtained by the production method of the present invention does not have a boundary between the surface layer and the skin layer on at least a part of the surface of the molded article. Therefore, even if the injection molded article obtained by the production method of the present invention is subjected to ultrasonic cleaning or the like, a portion where surface peeling occurs as shown in Fig. 1 (b) is reduced.

In contrast, Fig. 2 shows a multilayer structure (from the central portion to the surface portion) of the injection molded article obtained by the production method of the prior art. As shown in Fig. 2 (a), the surface layer exists on the entire surface of the injection molded article. Therefore, when performing ultrasonic cleaning or the like on the injection molded article obtained by the manufacturing method of the prior art, surface peeling occurs in the entire surface as shown in Fig. 2 (b).

3, the multilayer structure (from the center part to the surface part) of the injection molded article manufactured on the conditions satisfying said Formula (II) is shown. As shown in Fig. 3, among the injection molded articles obtained by the manufacturing method of the present invention, the injection molded articles produced under the conditions satisfying the above formula (II) show a tendency to completely eliminate the boundary between the surface layer and the skin layer. . Therefore, even if ultrasonic cleaning or the like is performed, an injection molded article is extremely hard to be peeled off.

As mentioned above, the injection molded article obtained by the manufacturing method of this invention does not produce the peeling of the surface, even if it carries out ultrasonic cleaning, and has the outstanding external appearance. Moreover, a high quality injection molded article can be obtained easily by setting mold temperature to 100 degrees C or less.

Example

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

<Material>

Liquid crystalline resin 1: "Vectra (trademark) E130i" glass fiber 30 mass% Filling material Melting point 335 degreeC, melt viscosity 40 Pa.s (made by Polyplastics, Inc.)

Insulation layer forming material 1: polyimide resin tape (Sumitomos Leem Co., Ltd. make), thermal conductivity 0.2W / m * K

Insulation layer forming material 2: Polyimide resin varnish (Fine Chemical Japan Co., Ltd. make), heat conductivity 0.2W / m * K

Heat insulation layer forming material 3: Polyimide resin film (made by Toray DuPont), heat conductivity 0.2W / m * K

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

&Lt; Example 1 >

Using the liquid crystalline resin 1 as a molding material, the heat insulating layer forming material 1 was attached to the surface of the mold cavity of the flat metal mold | die of width 20mm x length 50mm x thickness 0.5mm, and molding conditions, such as injection speed and mold temperature of Table 1, The molding was carried out to obtain an injection molded article. Conditions other than the molding conditions shown in the table are as follows.

[Molding conditions]

Cylinder set temperature: 350 ℃

Screw speed: 150rpm

&Lt; Example 2 >

Using liquid crystalline resin 1 as the molding material, the insulating layer forming material 2 was sprayed onto the mold cavity surface for flat plate molding of 40 mm ² × thickness 1 mm, and the polyimide surface was ground after curing at 250 ° C. for 1 hour. After adjusting to the thickness of the heat insulation layer in the inside, it shape | molded at the injection speed and mold temperature of Table 1, and obtained the injection molded article. Molding conditions other than those shown in Table 1 were the same as in Example 1.

&Lt; Example 3 >

An injection molded article was produced in the same manner as in Example 2 except that the molding conditions were changed to the conditions shown in Table 1. Molding conditions other than those shown in Table 1 were the same as in Example 1.

Example 4

Using the liquid crystalline resin 1 as a molding material, the insulating layer forming material 3 was attached to the mold cavity surface of the ISO standard test piece mold with a double-sided tape, and molded at the injection speed and mold temperature shown in Table 1 to obtain an injection molded product. Molding conditions other than those shown in Table 1 were the same as in Example 1.

&Lt; Example 5 >

An injection molded article was produced in the same manner as in Example 4 except that the molding conditions were changed to the conditions shown in Table 1. Molding conditions other than those shown in Table 1 were the same as in Example 1.

&Lt; Comparative Example 1 &

An injection molded article was produced in the same manner as in Example 4 except that the molding conditions were changed to the conditions shown in Table 1. Molding conditions other than those shown in Table 1 were the same as in Example 1.

&Lt; Comparative Example 2 &

An injection molded article was manufactured in the same manner as in Example 1 except that the heat insulation layer was not formed in the mold.

Comparative Example 3

An injection molded article was produced in the same manner as in Comparative Example 2 except that the molding conditions were changed to the conditions shown in Table 1. Molding conditions other than those shown in Table 1 were the same as in Example 1.

<Evaluation of the molded article>

About the injection molded article of an Example and a comparative example, cross cut peel test evaluation and ultrasonic cleaning test evaluation were performed.

[Cross cut peel test evaluation]

Evaluation was performed by the method according to JIS K5400, and evaluation was performed by the number of stripped lattice in 100 grids of 1 mm ² . The evaluation results are shown in Table 1.

 Ultrasonic Cleaning Test

The injection molded articles of Examples and Comparative Examples were immersed in water and ultrasonically cleaned for 1 minute, and the state of fibril generation on the surface was measured as whitening of the surface to evaluate the presence or absence of fibril generation. The evaluation results are shown in Table 1.

As can be seen from Table 1, it became clear that the injection-molded article obtained by the production method of the present invention is unlikely to cause surface peeling as can be clearly seen from the peeling number of the cross cut peel test evaluation. Thus, the injection molded article obtained by the manufacturing method of this invention can maintain the outstanding external appearance when surface peeling hardly occurs.

In addition, as apparent from Table 1, in Examples 1 to 3 and 5, no results of fibril generation were obtained from the ultrasonic cleaning test. In Examples 1 to 3 and 5, it was confirmed that there is no boundary between the surface layer and the skin layer on the surface of the injection molded article. Moreover, although the fibrillation generate | occur | produced on the surface in Example 4, the generation area is very small compared with the generation area of the fibrillation which generate | occur | produced on the molded article surface of a comparative example. Therefore, in Example 4, it was confirmed that the boundary of a surface layer and a skin layer exists in part.

It was confirmed that the production method of the present invention can produce high-quality injection molded articles even under conditions of 100 ° C or less of the mold temperature.

As can be clearly seen from the results of Examples 1 to 3 and 5 and the results of Example 4, there is no boundary between the surface layer and the skin layer by manufacturing the injection molded article under the conditions satisfying the above formula (II). It was confirmed that an excellent injection molded product can be obtained.

Claims (5)

In injection molding of the liquid crystalline resin composition, by using a mold having a heat insulating layer formed on the surface of the mold,
When the thickness of the heat insulation layer is t1 (µm), the injection speed is S (mm / sec), the thickness of the injection molded article is t2 (mm), and the mold temperature is T (° C), the following formula (I) is satisfied. A method for producing an injection molded article that is injection molded under molding conditions.
[Equation 1]
(t1 × S) / t2 + T

1000 ??? (Ⅰ)
The method of claim 1,
A method for producing an injection molded article, characterized in that injection molding is carried out under molding conditions satisfying the following formula (II).
&Quot; (2) &quot;
(t1 × S) / t2 + T

2000 ??? (II)
3. The method according to claim 1 or 2,
The said heat insulation layer is a heat conductivity of 5 W / m * K or less, The manufacturing method of the injection molded article characterized by the above-mentioned.
4. The method according to any one of claims 1 to 3,
The said heat insulation layer contains the polyimide resin, The manufacturing method of the injection molded article characterized by the above-mentioned.
The method according to any one of claims 1 to 4,
The manufacturing method of the injection molded article whose mold temperature T is 100 degrees C or less.

Images