JP2660547B2 - Insert molding method of thermotropic liquid crystal polymer - Google Patents

Description

The present invention relates to a method for insert molding a wholly aromatic liquid crystal polyester.

(Prior art) Conventionally, insert molding has been applied to the manufacture of electric and electronic parts, automobile parts, and the like as a means for integrating different materials having different functions. In recent years, there are many cases where heat resistance, toughness, dimensional accuracy, etc. are required for insert molded parts, and a wholly aromatic liquid crystal polyester has been used as a resin satisfying these requirements.

However, the wholly aromatic liquid crystal polyester has a high solidification rate in the mold, has poor wettability at the interface with the insert part, and easily peels off at the interface due to external stress or heat, resulting in misalignment, cracking, and gas. However, there is a drawback that it causes liquid leakage, and at present the use and shape of the product are limited.

(Problems to be Solved by the Invention) An object of the present invention is to solve the problem of poor wettability between an insert part and the polymer in the insert molding of the wholly aromatic liquid crystal polyester.

(Means for Solving the Problems) The present invention relates to a thermotropic liquid crystal polymer, in insert molding for embedding a metal or ceramic part, using a general formula as the thermotropic liquid crystal polymer. By using a wholly aromatic liquid crystal polyester containing a monomer unit represented by the formula, the surface temperature of the insert part at the time when the resin is filled into the mold during molding is set to 200 to 350 ° C to prevent interfacial delamination. And a molding method.

 This will be described in detail below.

The wholly aromatic liquid crystal polyester referred to in the present invention is a thermoplastic meltable polymer that exhibits optical anisotropy when melted. Such a polymer exhibiting optical anisotropy at the time of melting has a property that polymer molecular chains take a regular parallel arrangement in a molten state. The properties of the optically anisotropic molten phase can be confirmed by a normal polarization inspection method using an orthogonal polarizer.

Wholly aromatic liquid crystalline polyesters are generally made from monomers that are elongated, flat, rigid and have multiple chain extension bonds in either a coaxial or parallel relationship along the long chain of the molecule. .

As the constituent components of the polymer forming the optically anisotropic molten phase as described above, (A) at least one kind of aromatic dicarboxylic acid-based compound, (B) at least one kind of aromatic hydroxycarboxylic acid-based compound, ( And C) at least one aromatic diol compound. These may be configured alone, but are often configured in combination such as (A) and (C), (A), (B) and (C).

Examples of the aromatic dicarboxylic acid compound (A) include terephthalic acid, 4,4'-diphenyldicarboxylic acid, and 4,4'-
Triphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenylether-4,4'-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid , Diphenoxybutane-4,4'-dicarboxylic acid, diphenylethane-4,4'-dicarboxylic acid, isophthalic acid, diphenylether-3,3'-dicarboxylic acid, diphenoxyethane-3,3'-dicarboxylic acid, diphenyl Ethane-3,3 '
-Dicarboxylic acid, aromatic dicarboxylic acid such as 1,6-naphthalenedicarboxylic acid or chloroterephthalic acid, dichloroterephthalic acid, bromoterephthalic acid, methylterephthalic acid, dimethylterephthalic acid, ethylterephthalic acid,
Alkyl, alkoxy or halogen-substituted aromatic dicarboxylic acids such as methoxy terephthalic acid and ethoxy terephthalic acid are mentioned.

(B) Examples of the aromatic hydroxycarboxylic acid-based compound include aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphnoic acid, and 6-hydroxy-1-naphthoic acid; 3-methyl-4-hydroxybenzoic acid, 3,5-dimethyl-4-hydroxybenzoic acid, 2,6-dimethyl-4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3,5-dimethoxy- 4-hydroxybenzoic acid, 6
-Hydroxy-5-methyl-2-naphthoic acid, 6-hydroxy-5-methoxy-2-naphthoic acid, 2-chloro-
4-hydroxybenzoic acid, 3-chloro-4-hydroxybenzoic acid, 2,3-dichloro-4-hydroxybenzoic acid,
3,5-dichloro-4-hydroxybenzoic acid, 2,5-dichloro-4-hydroxybenzoic acid, 3-bromo-4-hydroxybenzoic acid, 6-hydroxy-5-chloro-2-naphthoic acid, 6-hydroxy Alkyl, alkoxy or halogen-substituted aromatic hydroxycarboxylic acids such as -7-chloro-2-naphthoic acid and 6-hydroxy-5,7-dichloro-2-naphthoic acid.

(C) As aromatic diols, 4,4'-dihydroxydiphenyl, 3,3'-dihydroxydiphenyl, 4,4 '
-Dihydroxytriphenyl, hydroquinone, resorcinol, 2,6-naphthalenediol, 4,4'-dihydroxydiphenylether, bis (4-hydroxyphenoxy) ethane, 3,3'-dihydroxydiphenylether, 1,6-naphthalenediol, Aromatic diols such as 2-bis (4-hydroxyphenyl) propane and bis (4-hydroxyphenyl) methane or chlorohydroquinone, methylhydroquinone, t-butylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4-chlororesorcinol, Alkyl, alkoxy or halogen-substituted aromatic diols such as 4-methylresorcin.

The wholly aromatic liquid crystal polyester used in the present invention can be produced from the above compound by various ester forming methods such as a melt acidilysis method and a slurry polymerization method.

In the wholly aromatic liquid crystal polyester used in the present invention, a part of one polymer chain is composed of a segment of a polymer that forms an anisotropic molten phase, and the remaining part is a thermoplastic resin that does not form an anisotropic molten phase. Polymers composed of resin segments are also included. Further, a composite of a plurality of wholly aromatic liquid crystal polyesters is also included.

The wholly aromatic liquid crystal polyester used in the present invention has at least a general formula A (co) polymer containing a monomer unit represented by the formula: Etc.

The liquid crystal polymer may be used alone as it is, or a filler or the like may be added as desired. Known fillers may be used as the filler, such as glass fiber, carbon fiber, metal fiber, and a fibrous reinforcing material surface-treated with an epoxy-based or silane-based compound, and also include silica, alumina, silica-alumina, and silica. Examples include inorganic fillers such as magnesia, titania, calcium carbonate, barium sulfate, talc, gypsum, and glass flake.

The material to be inserted into the resin is used for the purpose of taking advantage of its characteristics and compensating for the defects of the resin. Metals such as aluminum, copper, iron, brass, and alloys thereof, and inorganic solids such as ceramics, which are previously formed into parts such as rods, pins, and screws are used.

The insert component is heated directly or indirectly through a heat medium by a heat source such as an electric heater, electromagnetic induction heating, or a flame before or after being mounted on the mold.
The heating temperature is set so that the surface temperature of the insert part becomes 200 to 350 ° C. when the resin is filled in the mold.
If the temperature is low, the effect is small, and if the temperature is high, on the other hand, deformation and deterioration of the insert part and deterioration of the resin to be filled are caused, which is not preferable.

The time from the end of the heating of the insert part to the filling of the resin varies depending on the heat capacity, thermal conductivity, contact area with the mold, mold temperature, etc. of the insert part, but should be as short as possible. From the viewpoints of quality stability and safety, it is preferable that the heating operation and the mounting of the insert part in the mold are automated.

(Examples) Hereinafter, the present invention will be specifically described with reference to examples.

Example 1 Terephthalic acid, 4-hydroxybenzoic acid, and 4,
Zyder (trade name, manufactured by Amoco Performance Products Inc., USA) SRT-500 pellets, which is a thermotropic liquid crystal polymer composed of 4'-dihydroxydiphenyl,
SUMITOMO NESTAL SG25 type injection molding machine and a test piece molding die (6 mm long, 12 mm wide, inside a 12 mm long, 25 mm wide, 4 mm thick plate)
Using a die that inserts a ceramic part with a thickness of 1.5 mm), the temperature at the front of the cylinder is 390 ° C and the nozzle temperature is 3
90 ° C, Mold temperature 150 ° C, Injection time 6 seconds, Injection pressure 1300kg /
Injection molding was performed with cm ² and a cooling time of 15 seconds.

The ceramic insert was preheated to 400 ° C. in an oven and immediately set in a mold from the oven. The time taken from the oven to the start of injection was about 10 seconds. Do not close the mold,
After a lapse of the same time, the surface temperature of the insert part was measured with an infrared thermometer and found to be in the range of 300 to 330 ° C. The shape of the obtained molded product is shown in FIGS. 1 and 2.

A string was passed through a hole shown in 4 in the figure, a 10 kg weight was gently suspended, and the other end was fixed with a jig to determine whether or not the resin and the insert part had peeled off. The results were as shown in Table 1.

Example 2 Zyder Glass fiber 40 instead of SRT-500
% Zaider Same as Example 1 using FC-100
Table 1 shows the results of the tests performed in the same manner.

Example 3 The results of a test performed in the same manner as in Example 2 except that the insert part was heated to 300 ° C. in an oven are shown in Table 1.

Comparative Examples 1 and 2 Table 1 shows the results of tests performed in the same manner as in Examples 1 and 2 by setting the insert parts in a mold without heating them beforehand.

Example 4 Vectra (trade name of Celanese, USA) A130 pellets was used in place of Zyder in Example 1, cylinder front temperature 290 ° C, nozzle temperature 290 ° C, mold temperature 100 ° C, and other injection conditions were implemented. Injection molding was performed in the same manner as in Example 1.

The same ceramic insert part as in Example 1 was used, and after being heated to 300 ° C. in an oven, it was immediately set in a mold. When the surface temperature of the insert part was measured in the same manner as in Example 1, the temperature at the time of starting the injection was in the range of 220 to 235 ° C. Table 1 shows the results of testing the obtained molded articles in the same manner as in Example 1.

Comparative Example 3 Table 1 shows the results of a test performed in the same manner as in Example 4 by setting the insert component in a mold without heating it in advance.

(Effects of the Invention) According to the present invention, the following specific effects are obtained in the insert molding of a thermotropic liquid crystal polymer.

(1) Since the wettability between the insert component and the polymer is improved, the adhesion is improved, and the displacement, crack, gas, liquid leakage, and the like caused by separation of the interface are eliminated.

[Brief description of the drawings]

1 and 2 show an insert molded product used in an embodiment of the present invention. FIG. 1 is a top view and FIG. 2 is a side view. Thermotropic liquid crystal polymer 1, insert part 2,
Through holes 3,4.

Claims (2)

(57) [Claims] In the insert molding for embedding a metal or ceramic part in a thermotropic liquid crystal polymer, a general formula is used as the thermotropic liquid crystal polymer. By using a wholly aromatic liquid crystal polyester containing a monomer unit represented by the formula, the surface temperature of the insert part at the time when the resin is filled into the mold during molding is set to 200 to 350 ° C to prevent interfacial delamination. Molding method. 2. The molding method according to claim 1, wherein the insert part is made of a metal or ceramic alone or a composite material thereof.