KR101737036B1 - Liquid crystalline resin composition - Google Patents
Liquid crystalline resin composition Download PDFInfo
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- KR101737036B1 KR101737036B1 KR1020117015619A KR20117015619A KR101737036B1 KR 101737036 B1 KR101737036 B1 KR 101737036B1 KR 1020117015619 A KR1020117015619 A KR 1020117015619A KR 20117015619 A KR20117015619 A KR 20117015619A KR 101737036 B1 KR101737036 B1 KR 101737036B1
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- crystalline resin
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/0001—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor characterised by the choice of material
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/04—Reinforcing macromolecular compounds with loose or coherent fibrous material
- C08J5/0405—Reinforcing macromolecular compounds with loose or coherent fibrous material with inorganic fibres
- C08J5/043—Reinforcing macromolecular compounds with loose or coherent fibrous material with inorganic fibres with glass fibres
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K7/00—Use of ingredients characterised by shape
- C08K7/02—Fibres or whiskers
- C08K7/04—Fibres or whiskers inorganic
- C08K7/14—Glass
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L101/00—Compositions of unspecified macromolecular compounds
- C08L101/12—Compositions of unspecified macromolecular compounds characterised by physical features, e.g. anisotropy, viscosity or electrical conductivity
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/0005—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor using fibre reinforcements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/0013—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor using fillers dispersed in the moulding material, e.g. metal particles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/0079—Liquid crystals
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
- B29K2105/16—Fillers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2709/00—Use of inorganic materials not provided for in groups B29K2703/00 - B29K2707/00, for preformed parts, e.g. for inserts
- B29K2709/08—Glass
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2300/00—Characterised by the use of unspecified polymers
- C08J2300/12—Polymers characterised by physical features, e.g. anisotropy, viscosity or electrical conductivity
Abstract
Provided is a technique for stabilizing a measurement time to a short time and keeping a cushion amount small while maintaining good physical properties of a liquid crystal resin composition containing glass fibers.
The glass beads are blended in a total amount of 4% by mass to 7% by mass with respect to the mixture including the liquid crystalline resin and the glass fiber. In particular, the glass fiber is preferably blended in an amount of 20% by mass to 40% by mass in the total amount of the liquid crystalline resin composition. According to the present invention, even in injection molding using a liquid crystalline resin material having a high melting point and a low viscosity, the liquid crystal resin composition containing glass fibers can be stably held for a long time while keeping good physical properties, .
Description
TECHNICAL FIELD The present invention relates to a technique for stabilizing a metering time when injection molding a liquid crystal resin composition containing glass fibers.
Liquid crystalline resins represented by liquid crystalline polyester resins are widely used as high-performance engineering plastics because they have excellent mechanical strength, heat resistance, chemical resistance, and electrical properties in a well-balanced manner. Particularly, most of the liquid crystalline resin is used for injection molding.
The liquid crystalline resin in which the liquid crystalline resin is filled with a fibrous reinforcement represented by glass fiber or carbon fiber or an inorganic powder such as silica, mica, clay, glass beads or the like has good balance between fluidity and mechanical strength It becomes a material suitable for an electric / electronic part having a thin wall portion or a complicated shape. For example, relay parts, coil bobbins, connectors, volume parts, motor parts such as commutators and separators, and seal materials such as coils, crystal oscillators, and IC chips.
There is disclosed a liquid crystal resin composition comprising two or more kinds of glass fibers as a liquid crystal resin composition excellent in mechanical properties, dimensional stability and heat resistance of a thin-walled portion including an inorganic filler such as glass fiber as described above Patent Document 1: JP-A-2008-13702).
It is also known that glass beads, one of the inorganic fillers, are blended in the liquid crystalline resin composition for the same purpose as glass fibers. What has hitherto been known as a liquid crystal polymer blended with an inorganic filler such as glass fiber has been improved to some extent in heat resistance, mechanical strength and anisotropy of a liquid crystal polymer, but fluidity, dimensional accuracy and appearance of a molded article at the time of molding are not necessarily sufficient. Thus, a liquid crystalline resin composition comprising 100 parts by mass of a liquid crystalline resin and 5 parts by mass to 200 parts by mass of glass beads is disclosed (Patent Document 2: JP-A-08-325446).
However, most of the molded articles made of the liquid crystalline resin composition as described in the above patent documents were molded by injection molding. This is because the injection molding method can be easily molded even in the case of a resin molded product having a complicated shape.
The liquid crystalline resin is characterized by low viscosity. Since the viscosity is low, the molten liquid crystalline resin composition exits the backflow prevention valve provided at the end of the screw and flows backward, and the metering time is not stable.
In the conventional injection molding, the resin material injected from the hopper melts by the rotation of the screw and is sent to the front portion of the screw. However, since the resin material containing the liquid crystalline resin has a high melting point, There is a problem that the weighing time becomes long.
Furthermore, in the case of a liquid crystalline resin material having a high melting point and a low viscosity, the molten resin material can not be smoothly sent to the front portion of the screw by rotation of the screw, and the molten resin material is sent to the front portion of the screw . If the molten resin material is sent to the front side of the screw in the state of containing air, the filling density becomes smaller as the air is enclosed and the quality of the molded article becomes uneven.
Further, in order to make the holding pressure effective, a small amount of molten resin at the tip end of the screw is released. The amount of resin remaining at the tip is referred to as a cushion amount. If such a cushion amount varies from shot to shot, a high-quality molded product can not be stably molded. Further, since the resin remaining at the tip end is used for the next molding, if the amount of cushion is increased, many resins injected in the next molding are put in a high temperature state for a long time, leading to deterioration of physical properties of the molded article.
As described above, it is required to stabilize the metering time shortly and to stabilize the amount of cushion to a small extent. However, if the above point is to be improved, deterioration of other properties will be caused. Therefore, the metering time can be shortly stabilized while maintaining good physical properties, It is difficult to stabilize.
SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a technique of stabilizing a metering time shortly and keeping a cushion amount small while maintaining good physical properties of a liquid crystal resin composition containing glass fibers .
The present inventors have conducted intensive studies to solve the above problems. As a result, it has been found that the above problems can be solved by blending glass beads in an amount of 4% by mass to 7% by mass with respect to a mixture of the liquid crystalline resin and the glass fiber, thereby completing the present invention. More specifically, the present invention provides the following.
(1) A liquid crystalline resin composition for injection molding, comprising a liquid crystalline resin, glass fiber and glass beads, wherein the amount of the glass beads is 4 mass% to 7 mass%.
(2) The liquid crystalline resin composition for injection molding according to (1), wherein the glass fiber is blended in an amount of 20% by mass to 40% by mass in the total amount of the liquid crystalline resin composition for injection molding.
(3) The liquid crystalline resin for injection molding according to (1) or (2) above, wherein the liquid crystalline resin has a melting point of 320 ° C or higher and a viscosity at 380 ° C at a shear rate of 1000sec -1 or lower. Composition.
(4) The liquid crystalline resin composition for injection molding according to any one of claims 1 to 3, which has a melt viscosity at 380 DEG C and a shear rate of 1000 sec < -1 > A molded article having a load deflection temperature of 300 DEG C or higher at 1.8 MPa measured by a method according to the present invention.
According to the present invention, by mixing 4% by mass to 7% by mass of the above-mentioned glass beads in a liquid crystal resin composition for injection molding containing a liquid crystalline resin, glass fiber and glass beads, The metering time can be shortened and the cushioning amount can be stabilized to a low level while maintaining physical properties.
Hereinafter, one embodiment of the present invention will be described in detail, but the present invention is not limited to the following embodiments, but can be carried out by appropriately changing the scope of the present invention.
The present invention is characterized in that glass beads are blended in an amount of 4% by mass to 7% by mass in a liquid crystalline resin composition for injection molding comprising a liquid crystalline resin, glass fiber and glass beads.
<Liquid Crystalline Resin Composition>
The liquid crystalline resin composition used in the present invention includes a liquid crystalline resin, glass fiber, and glass beads. Hereinafter, the liquid crystalline resin composition will be described in the order of liquid crystalline resin, glass fiber, and glass beads.
[Liquid crystalline resin]
The liquid crystalline resin used in the present invention refers to a melt-processible polymer having properties capable of forming an optically anisotropic melt phase. The properties of the anisotropic molten phase can be confirmed by conventional polarimetry using an orthogonal polarizer. More specifically, the identification of the anisotropic molten phase can be carried out by observing a molten sample placed on a Leitz hot stage using a Leitz polarization microscope under a nitrogen atmosphere at a magnification of 40 times. The liquid crystalline resin which can be applied to the present invention, when examined between orthogonal polarizers, normally transmits polarized light even when it is in the melt stop state, and exhibits optical anisotropy.
The liquid crystalline resin is not particularly limited, but an aromatic polyester or an aromatic polyester amide is preferable, and a polyester partially containing an aromatic polyester or an aromatic polyester amide in the same molecular chain is also in the range . They have a logarithmic viscosity (I.V.) of at least about 2.0 dl / g, more preferably from 2.0 to 10.0 dl / g, when dissolved at a concentration of 0.1% by weight in pentafluorophenol at 60 占 폚.
As the aromatic polyester or aromatic polyester amide of the liquid crystalline resin applicable to the present invention, it is particularly preferable to use at least one compound selected from the group of aromatic hydroxycarboxylic acid, aromatic hydroxyamine and aromatic diamine as the component And an aromatic polyester amide.
More specifically,
(1) a polyester mainly composed of one or more kinds of aromatic hydroxycarboxylic acids and derivatives thereof;
(2) at least one of (a) an aromatic hydroxycarboxylic acid and a derivative thereof, (b) one or more of an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid and a derivative thereof, And (c) at least one or more kinds of aromatic diols, alicyclic diols, aliphatic diols and derivatives thereof;
(3) at least one or more of (a) an aromatic hydroxycarboxylic acid and a derivative thereof, (b) at least one of an aromatic hydroxyamine, an aromatic diamine and a derivative thereof, and (c) A polyester amide comprising one or more of dicarboxylic acid, alicyclic dicarboxylic acid and derivatives thereof;
(4) at least one or more of (a) an aromatic hydroxycarboxylic acid and a derivative thereof, (b) at least one of an aromatic hydroxyamine, an aromatic diamine and a derivative thereof, (c) (D) at least one or more of an aromatic diol, an alicyclic diol, an aliphatic diol and a derivative thereof, and at least one polyester resin Amides and the like. A molecular weight regulator may be used in combination with the above-mentioned components, if necessary.
Preferable examples of the specific compound constituting the liquid crystalline resin applicable to the present invention include aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, 2,6-di Aromatic diols such as hydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl, hydroquinone, resorcin, compounds represented by the following formulas (I) and (II) Aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 4,4'-diphenyl dicarboxylic acid, 2,6-naphthalene dicarboxylic acid and compounds represented by the following formula (III); p-aminophenol, p-phenylenediamine, and other aromatic amines.
(X: an alkylene (C1 ~ C4), alkylidene, -O-, -SO-, -SO 2 - , a group -S-, selected from -CO-.)
(Y is a group selected from - (CH 2 ) n - (n = 1 to 4), -O (CH 2 ) n O- (n = 1 to 4)
The present invention is characterized in that the metering time is stabilized short and the amount of cushion is stabilized small. When a liquid crystalline resin having a high melting point is used, there is a tendency that a resin material such as a resin pellet can not be smoothly sent to the front portion of the screw. This is because the resin pellets containing a liquid crystalline resin having a high melting point are difficult to melt and the pellets are welded together to increase the weighing time. The melting point of the liquid crystalline resin susceptible to the above problems is 320 DEG C or higher. By blending a certain amount of glass beads in the liquid crystalline resin composition as in the present invention, even when a resin material containing a liquid crystalline resin having the melting point or higher is used, the resin material can be smoothly sent to the front side of the screw, .
Further, when a liquid crystalline resin having a low viscosity is used, the molten resin sent to the front portion of the screw tends to escape from the backflow prevention valve and flow backward, or the cushion amount is not stabilized. The viscosity of the liquid crystalline resin which easily causes such a problem is 55 Pa · sec or less. By mixing glass beads in a specific amount with the liquid crystalline resin composition as in the present invention, it is possible to easily solve the problem of backflow of the molten resin and unstable amount of cushion even if the liquid crystalline resin having the above viscosity is used.
[Fiberglass]
As the glass fiber contained in the liquid crystalline resin composition of the present invention, the fiber length, fiber diameter and the like are not particularly limited and conventionally known ones can be used. The fiber length and fiber diameter of the glass fiber can be appropriately changed according to the desired properties.
Glass fiber or milled fiber of chopped strand having a fiber diameter of 5 탆 to 15 탆 and a fiber length of 3 mm usually has a glass fiber with a weight average fiber length of 50 탆 to 700 탆, If a liquid crystalline resin material containing glass fibers is made of resin pellets or the like and used as a raw material, the measurement time may become long, the measurement time may become unstable, or the amount of cushion may be unstable. The problem of the liquid crystalline resin material including glass fibers as described above can be easily solved by blending a specific amount of glass beads with a mixture of liquid crystalline resin and glass fiber as in the present invention to make a liquid crystalline resin composition .
The content of the glass fiber contained in the liquid crystalline resin composition is not particularly limited, but if the liquid crystalline resin composition contains 20% by mass to 40% by mass, the measurement time becomes long, the measurement time becomes unstable, the cushion amount becomes unstable easy to do. In addition, a molded article formed by molding a liquid crystalline resin composition having a glass fiber content of 20% by mass to 40% by mass has various properties such as mechanical properties and is used for various purposes. Therefore, However, the problem can be easily solved by blending a certain amount of glass beads.
[Glass beads]
The liquid crystalline resin composition of the present invention is characterized by containing 4% by mass to 7% by mass of glass beads relative to 100% by mass of the total composition. When the glass beads are contained in the liquid crystalline resin composition in the above-described range, the liquid crystal resin composition containing glass fibers can be stably kept in a short time while maintaining good physical properties, and the cushioning amount can be stabilized to a low level. When the content of the glass beads is less than 4% by mass, deviation of the curing time and the curing amount becomes large, which is not preferable. If the content of the glass beads is more than 7% by mass, problems such as deterioration of moldability due to an increase in melt viscosity and deterioration of physical properties of the molded article formed by molding the liquid crystalline resin composition are not preferable. Preferably, the melt viscosity at 380 DEG C at a shear rate of 1000 sec < -1 >
The average particle diameter of the glass beads is not particularly limited, but is preferably 5 탆 to 30 탆. The average particle diameter of the glass beads is usually 5 占 퐉 or more, and when the average particle diameter of the glass beads is 30 占 퐉 or less, this is preferable from the viewpoint of thin wall fluidity.
[Liquid crystalline resin composition]
The liquid crystalline resin composition of the present invention includes the above-mentioned liquid crystalline resin, glass fiber and glass beads. By making a liquid crystalline resin composition comprising glass beads in an amount of 4% by mass to 7% by mass based on 100% by mass of the total composition of the liquid crystal resin and the glass fiber, The metering time can be shortened and the cushioning amount can be stabilized to a low level while maintaining good physical properties.
The reason why the above effect can be obtained is presumably because the temperature range until the liquid crystalline resin composition is softened and melted by blending the glass beads becomes small. As the " appropriate melt viscosity " showing the above characteristics, the melt viscosity at 380 DEG C at a shear rate of 1,000 sec < -1 > is preferably 35 Pa · sec or more, more preferably 40 Pa · sec or more, ㆍ sec.
Various inorganic fillers have been blended for the purpose of improving the physical properties of the molded articles obtained in the past. Examples of the inorganic filler that can be added to the liquid crystalline resin include glass fiber, asbestos fiber, silica fiber, silica-alumina fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber , And metallic fibrous materials such as stainless steel, aluminum, titanium, copper and brass. Examples of the powdery filler include carbon black, graphite, silica, quartz powder, glass beads, mud glass fiber, glass balloon, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, Oxides of metals such as alumina, carbonates of metals such as calcium carbonate and magnesium carbonate, sulfates of metals such as calcium sulfate and barium sulfate, other ferrites such as silicon carbide , Silicon nitride, boron nitride, various metal powders, and the like. Examples of the plate-like filler include mica, glass flakes, various metal foils and the like. The present invention can be realized by a combination of glass fibers and glass beads. In other combinations, it is presumed that the same effect as that of the present invention can not be obtained because the temperature width until the liquid crystalline resin composition is melted and melted is not sufficiently narrowed.
One of the characteristics of the present invention is that it is possible to maintain good physical properties of the liquid crystalline resin composition containing glass fibers as described above. The term "maintaining good physical properties" means that the physical properties are not deteriorated at all by blending the glass beads. Examples of physical properties that are likely to deteriorate include mechanical properties typified by load deflection temperature and flexural strength of a molded article obtained by molding a liquid crystalline resin composition.
<Injection Molding>
The liquid crystalline resin composition of the present invention is used as a material and molded by an injection molding method to produce a molded article. The injection molding can be divided into, for example, a metering process, an injection process, and a pressurization / cooling process. The molding apparatus used may be a conventional injection molding apparatus known in the art.
[Measuring process]
The metering step is a step of plasticizing and measuring the resin. The resin pellets made of the liquid crystalline resin composition described above are transported from the hopper side to the nozzle side side by the rotation of the screw. Then, the molten liquid crystalline resin composition is gathered at the front portion of the screw.
Since the conventional liquid crystalline resin composition has a low viscosity, the molten resin may be conveyed while containing air, resulting in defects such as insufficient filling or deflection. However, in the present invention, By mass to 7% by mass, the liquid crystalline resin composition can be prevented from containing air by imparting an appropriate viscosity to the liquid crystalline resin composition as described above.
As described above, when the molten resin is sent to the front side of the screw while containing air, the air is taken out by the back pressure. The term "back pressure" refers to a pressure to pressurize the resin by moving it in the direction of injection opposite to the retreat direction of the screw when the screw is retracted due to the molten resin sent to the tip. A backflow prevention valve is provided at the front portion of the screw to prevent the molten resin from flowing backward. However, since the molten liquid crystal resin composition has a low viscosity, the backflow prevention valve is escaped. However, in the present invention, since the liquid crystalline resin composition that has been melted is appropriately given a viscosity as described above, backflow can be prevented. When injection molding is performed using the liquid crystalline resin composition of the present invention as a material, the back pressure is preferably 1 MPa to 5 MPa.
Further, when the liquid crystalline resin composition is injection molded, a plurality of resin pellets tends to be easily welded during transportation. When the groove of the screw is shallow compared to the size of the resin pellet mass produced by welding, the transfer of the molding material is not smooth. If the transfer is not performed smoothly, the metering time is prolonged and the productivity of the injection molded article is lowered. Further, since the transfer is not performed smoothly, the difference in the metering time for each shot becomes large. The quality of the injection-molded product obtained due to non-uniformity of the metering time is affected. In the present invention, glass beads are blended to a mixture of a liquid crystalline resin and glass fiber so as to be 4% by mass to 7% by mass based on 100% by mass of the total composition, thereby completing the above- Time can be stabilized.
The term " stabilization of metering time " means that the metering time for each shot is not exactly the same, and the deviation between the maximum metering time in 30 shots and the minimum metering time is within 5 seconds. If the deviation of the weighing time is within the above range, the decrease in productivity can be sufficiently solved and the quality of the obtained molded article is hardly affected.
[Injection process]
The injection step is a step of extruding molten resin from a cylinder into a mold. The injection speed and injection pressure are injected at a desired injection speed by the molding material to be used.
After injection, a small amount of molten resin is left at the tip of the screw to enable the holding pressure to be effective. The amount of resin remaining at the tip is called the cushion amount. When the amount of cushion is increased, the resin remaining at the tip is used for the next molding, and the resin is put in a high temperature state for a long time, leading to deterioration of physical properties. Also, the variation in the amount of cushion affects the quality of the molded article. By using the liquid crystalline resin composition of the present invention, variation of cushioning amount can be suppressed to 1.0 mm or less while satisfactorily maintaining other physical properties. The deviation of the preferable cushion amount indicates the difference between the maximum value and the minimum value by measuring 30 shots.
[Holding pressure and cooling process]
The repressurization process is a process of continuing the pressurization from the injection molding machine to the resin in the mold at the beginning of the cooling process after the injection process and replenishing the shrinkage amount of the resin after cooling. In particular, when the liquid crystalline resin composition of the present invention is used, since the cushion amount is stable as described above, the holding pressure can be made effective.
In the injection molding, in order to increase the productivity of the molded product, the resin is weighed while the resin in the mold is cooled during the cooling step by retreating the screw. If the resin takes a long time to cool, the influence on the productivity is small even if the metering time is somewhat long. However, since the liquid crystalline resin has a short cooling time, it is necessary to stabilize the metering time short. By using the liquid crystalline resin composition of the present invention, the weighing time can be stabilized.
Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited by these examples.
<Material>
Liquid crystalline resin: Vectra T950 (manufactured by Polyplastics) Melt viscosity: 48 Pa · sec
Fiber strand glass fiber: ECS03T-786H (manufactured by Nippon Electric Glass Co., Ltd.) fiber diameter 10 탆, fiber length 3 mm
Glass beads: EGB 731 (manufactured by Potters Valotini Co., Ltd.) Average particle diameter 18 탆
Spherical silica: SC2000-ZD (manufactured by Admatechs Co., Ltd.) average particle diameter 0.55 mu m
Talc: Crown talc PP (manufactured by Matsumura Industrial Co., Ltd.) Average particle diameter 2.3 탆
<Examples>
The materials shown in Table 1 were dry-blended at the ratios shown in Table 1, and kneaded pellets were produced using a twin-screw extruder ("TEX30 alpha type" manufactured by Nihon Steel Mill). The following evaluations were carried out using the liquid crystalline resin composition of this example.
[Measurement of melt viscosity]
The apparent melt viscosity under the conditions of a temperature of 380 DEG C and a shear rate of 1000 sec < -1 > was measured according to ISO 11443 by means of a capillary rheometer ("Capiolograph 1B: piston diameter 10 mm" manufactured by TOYO SEIKI Co., Ltd.). For the measurement, an orifice having an inner diameter of 1 mm and a length of 20 mm was used. The measurement results are shown in Table 1.
[Measurement of load deflection temperature]
(4 mm x 0 mm x 0 mm) was molded under the following molding conditions using a kneading pellet and a molding machine ("SE100DU" manufactured by Sumitomo Heavy Industries, Ltd.) of the embodiment. Next, the load deflection temperature was measured in accordance with ISO 75-1, 2. The results of measurement of the deflection temperature of the load are shown in Table 1.
(Molding conditions)
Cylinder temperature: 380 ℃
Mold temperature: 90 ℃
Back pressure: 1.0 MPa
Injection speed: 33m / sec
[Metering stability]
The weighing when a flat test piece of 80 mm x 0 mm x 5 t (measuring stroke 50 mm) was molded under the following molding conditions using the kneading pellets and the molding machine (J110-AD molding machine (screw diameter 35 mm) The variation of time and cushion amount was measured. 30 shots were made to calculate the difference between the average weighing time, the average cushion amount, the difference between the maximum weighing time and the minimum weighing time, and the maximum and minimum values deviating from the reference weighing position. The results are shown in Table 1.
(Molding conditions)
Cylinder temperature: 380 ℃
Mold temperature: 80 ℃
Number of screw revolutions: 220 rpm
Back pressure: 4MPa
[Bending strength]
The bending strength was measured by a method according to ISO 178 using the same test piece as that used for the measurement of the deflection temperature of load. The measurement results are shown in Table 1.
<Comparative Example>
The materials shown in Table 1 were dry-blended at the ratios shown in Table 1, and kneaded pellets were produced in the same manner as in Example 1. [ The kneading pellets of this comparative example were used to evaluate melt viscosity, deflection temperature under load, and stability of metering in the same manner as in Examples. The evaluation results are shown in Table 1.
As clearly shown in Table 1, in Examples 1 and 2 in which the blending amount of glass beads is in the range of 4% by mass to 7% by mass in the total composition, the melt viscosity of the liquid crystalline resin composition is in the range of 35 Pa · sec or more , The average metering time is as short as 12 seconds and the deviation of the metering time is as small as less than 4 seconds even though there is no decrease in the deflection temperature of the load. Also, the cushion amount is not more than 3.4 mm, and the variation of the cushion amount is less than 0.4 seconds. In Comparative Example 1 in which glass beads were not blended at all, the weighing time was long, the deviation was large, and the variation in cushion amount was large. On the other hand, when the amount of the glass beads exceeds 7% by mass, as is apparent from Comparative Examples 3 and 4, the melt viscosity becomes poor and the deflection temperature of the load starts to decrease and the physical properties are lowered.
As can be clearly seen from the results of Example 2 and Comparative Examples 5 and 6, Comparative Example 5 using spherical silica instead of glass beads and Comparative Example 6 using talc showed a variation in average metering time , It was confirmed that the variation of the average cushion amount was large.
From the above results, the liquid crystal resin composition containing glass fibers and the glass beads were blended so as to be 4% by mass to 7% by mass based on 100% by mass of the total composition, It was confirmed that the metering time could be shortened and the cushioning amount could be stabilized to a low level while maintaining good physical properties.
Claims (4)
The blending amount of the glass beads is 4% by mass to 7% by mass,
Wherein the glass fiber is blended in an amount of 20% by mass to 40% by mass in the total amount of the liquid crystal resin composition for injection molding.
Wherein the liquid crystalline resin has a melting point of 320 ° C or higher and a viscosity at 380 ° C at a shear rate of 1000sec -1 of 55 Pa · sec or less.
A molded article having a load deflection temperature of 300 DEG C or higher at 1.8 MPa as measured by the method according to ISO 75-1 and ISO 75-2.
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| PCT/JP2009/006629 WO2010067561A1 (en) | 2008-12-11 | 2009-12-04 | Liquid crystalline resin composition |
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| TWI586750B (en) * | 2011-02-28 | 2017-06-11 | 住友化學股份有限公司 | Liquid crystal polyester composition and process for producing the same |
| JP6329739B2 (en) * | 2013-08-29 | 2018-05-23 | ウィンテックポリマー株式会社 | Method for suppressing variation in measurement time of thermoplastic aromatic polyester resin composition |
| CN108701565B (en) * | 2015-11-20 | 2020-05-08 | 柏恩氏株式会社 | Electronic device case, method for manufacturing electronic device case, and circuit breaker provided with electronic device case |
| SG11201809000VA (en) * | 2016-04-15 | 2018-11-29 | Polyplastics Co | Liquid crystal resin composition |
| TW202104406A (en) * | 2019-05-16 | 2021-02-01 | 日商寶理塑料股份有限公司 | Liquid crystalline resin composition and molded body using same |
| JP6643516B1 (en) | 2019-05-17 | 2020-02-12 | 住友化学株式会社 | Pellet mixture and injection molding |
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| JP2531307B2 (en) * | 1991-01-08 | 1996-09-04 | 住友化学工業株式会社 | Wholly aromatic polyester resin composition and oven wear |
| JP3562122B2 (en) * | 1995-03-31 | 2004-09-08 | 東レ株式会社 | Glass bead reinforced liquid crystalline resin composition |
| JP4118425B2 (en) * | 1998-12-18 | 2008-07-16 | ポリプラスチックス株式会社 | Liquid crystalline polymer composition for connector and connector |
| JP2000273320A (en) * | 1999-03-19 | 2000-10-03 | Polyplastics Co | Liquid crystal polymer composition for optical pickup and optical pickup |
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| TW538094B (en) * | 2000-04-20 | 2003-06-21 | Ueno Seiyaku Oyo Kenkyujo Kk | Liquid crystal polyester resin composition |
| JP2004168841A (en) * | 2002-11-18 | 2004-06-17 | Toray Ind Inc | Liquid crystalline resin composition |
| JP4498810B2 (en) * | 2004-04-16 | 2010-07-07 | ポリプラスチックス株式会社 | Liquid crystal resin composition |
| JP4912620B2 (en) * | 2005-05-30 | 2012-04-11 | ポリプラスチックス株式会社 | Polyarylene sulfide resin composition and injection molded article |
| CN101305056B (en) * | 2005-10-13 | 2011-09-14 | 宝理塑料株式会社 | Liquid crystalline resin composition for use in injection molding |
| JP4813196B2 (en) * | 2006-02-02 | 2011-11-09 | ポリプラスチックス株式会社 | Polyarylene sulfide resin composition for molded article having cylindrical shape and molded article having cylindrical shape |
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