JPH0692798B2 - Pump impeller - Google Patents

Description

The present invention relates to a pump impeller for a fluid pump, which is also called a regenerative pump, a surface flow pump, or a vortex flow pump.

[Conventional technology and problems]

Details of the regenerative pump are detailed in, for example, [Handbook of Hydromechanical Engineering, page 480 (published 43.9.20 Showa)] and [Handbook of Mechanical Engineering, pages 9-69 (published 48.6.15, Showa 4)].
As shown in FIGS. 1 to 4, it is composed of an impeller 1 and a casing 2. Both sides of the impeller are exactly the same, and a short fan-shaped groove 3 extending in the radial direction is provided around the impeller to act as a blade. The casing 2 has a shape in which a side plate is applied to a single surface of a short cylinder, and has a structure in which a working fluid passage 4 is provided on the periphery. There are two gaps in the regeneration pump impeller. The gap between the pump impeller and the partition wall between the suction port 6 and the discharge port 7 shown at C ₂ in FIG. 3 and C ₁ in FIG. Further, between the pump impeller both surfaces and the casing liner 5 in contact therewith, if these gaps become large, it causes leakage loss and greatly affects the pump efficiency characteristic. Therefore, attention is paid to work and assembly, and efforts are made to make the gap as small as possible without causing friction. On the other hand, as a recent tendency, it is not necessary to explain much that the plastic parts are being made plastic, a wide range of metal parts are being replaced by plastic parts, and the pump parts are also being made plastic. In these cases, attention is focused on the rust resistance of plastics, and it is limited to parts whose discharge efficiency, dimensional accuracy, strength, etc. can be neglected. At present, metal parts are still used for industrial pumps in which accuracy of discharge amount, operation efficiency, durability, etc. are problems.

One of the reasons plastics parts are not used in industrial pumps is that the molding accuracy is insufficient.The second is that water and solvent resistance is low and they expand due to water and solvent. This is because the design in consideration, that is, the gap is increased, and the discharge effect of the pump is deteriorated.

In the case of a regenerative pump, it is usually said that it is desirable that this moment is about 0.1 mm or less.

Until now, it has been impossible to manufacture plastic impellers with such accuracy, and only barely used phenol resin moldings have been used. However, in this case, it is not possible to finish to the prescribed size by compression molding, and after rough molding, it is necessary to cut the molded product and finish it to the prescribed size. It is used only in part because it has a low value and often breaks.

[Means for solving problems]

The present inventors have arrived at the present invention as a result of various studies on making plastics for pump impellers.

That is, the present invention is a melt-processible polymer capable of forming an anisotropic melt phase, preferably having a weight average molecular weight of about 2,000 to 200,0.
The present invention provides a pump impeller related to a pump impeller made of polymer 00, which can solve all the drawbacks of the conventional plastic pump impeller such as strength, dimensional accuracy, water resistance, and solvent resistance.

The melt-processable polymer (liquid crystalline polymer) capable of forming an anisotropic melt phase used in the present invention has a property that polymer molecular chains take a regular parallel arrangement in a molten state. The state in which the molecules are arranged in this manner is often called a liquid crystal state or a nematic phase of a liquid crystal substance. Such polymers are generally elongate, flattened, fairly rigid along the long axis of the molecule, and are composed of monomers that have multiple chain extension bonds, usually in either coaxial or parallel relationship. Manufactured.

The properties of the anisotropic molten phase can be confirmed by a conventional polarization inspection method using a crossed polarizer. More specifically, the confirmation of the anisotropic molten phase can be performed by using a Leitz polarization microscope and observing the sample placed on the Leitz hot stage under a nitrogen atmosphere at a magnification of 40 times. The polymer is optically anisotropic. That is, it transmits light when inspected between crossed polarizers. If the sample is optically anisotropic, polarized light will be transmitted even if it is stationary.

As the constituent component of the polymer forming the anisotropic molten phase as described above, one or more of aromatic dicarboxylic acid and alicyclic dicarboxylic acid is used. 1 of aromatic diol, alicyclic diol and aliphatic diol One or more Aromatic hydroxycarboxylic acids One or more Aromatic thiol carboxylic acids One or more Aromatic dithiols, aromatic thiol phenols 1
One or more of these include aromatic hydroxyamines, one or more of aromatic diamines, etc., and the polymer that forms the anisotropic melt phase consists only of polyester II) consisting of I) Polyester III) consisting of polyester IV) and polythiol ester consisting only of V) Polythiol ester consisting of V) VI) and polythiol ester VII) consisting of polyesteramide VIII) and a combination of polyesteramide consisting of Composed of.

Furthermore, although not included in the category of the combination of the above components,
Aromatic polyazomethine is included in the polymer forming the anisotropic molten phase, and specific examples of such a polymer include poly (nitrilo-2-methyl-1,4-phenylene nitriloethylidyne-1,4-phenyleneethyl). Lysine); poly (nitrilo-2-methyl-1,4-phenylene nitrilomethylidine-1,4-phenylenemethylidine); and poly (nitrilo-2-chloro-1,4-phenylene nitrilomethylidine-1,4) -Phenylenemethylidine).

Furthermore, although not included in the category of the combination of the above components,
Polyester carbonate is included as a polymer forming the anisotropic molten phase. It consists essentially of 4-oxybenzoyl units, dioxyphenyl units, dioxycarbonyl units and terephthaloyl units.

The compounds constituting the above-mentioned 1) to VIII) are listed below.

Aromatic dicarboxylic acids include terephthalic acid and 4,4'-
Diphenyldicarboxylic acid, 4,4'-triphenyldicarboxylic acid, 2,6-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, Aromatic dicarboxylic acids such as 3'-dicarboxylic acid, diphenylethane-3,3'-dicarboxylic acid, naphthalene-1,6-dicarboxylic acid,
Or chloroterephthalic acid, dichloroterephthalic acid,
Examples thereof include alkyl, alkoxy or halogen substitution products of the above aromatic dicarboxylic acids such as bromoterephthalic acid, methyl terephthalic acid, dimethyl terephthalic acid, ethyl terephthalic acid, methoxy terephthalic acid and ethoxy terephthalic acid.

Examples of the alicyclic dicarboxylic acid include trans-1,4-cyclohexanedicarboxylic acid, cis-1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid and other alicyclic dicarboxylic acids or trans-1,4- ( 1-methyl) cyclohexanedicarboxylic acid, trans-1,4-
Examples thereof include alkyl-, alkoxy- or halogen-substituted products of the above alicyclic dicarboxylic acids such as (1-chloro) cyclohexanedicarboxylic acid.

Aromatic diols include hydroquinone, resorcin, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxytriphenyl, 2,6-naphthalenediol, 4,4'-
Dihydroxydiphenyl ether, bis (4-hydroxyphenoxy) ethane, 3,3′-dihydroxydiphenyl, 3,3′-dihydroxydiphenyl ether, 1,6-naphthalenediol, 2,2-bis (4-hydroxyphenyl) propane, 2, 2-bis (4-hydroxyphenyl)
Aromatic diols such as methane, chlorohydroquinone, methylhydroquinone, 1-butylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone: 4-chlororesorcin,
Examples thereof include alkyl-, alkoxy- or halogen-substituted products of the above aromatic diols such as 4-methylresorcin.

As the alicyclic diol, trans-1,4-cyclohexanediol, cis-1,4-cyclohexanediol,
Trans-1,4-cyclohexanedimethanol, cis-
Alicyclic diols such as 1,4-cyclohexanedimethanol, trans-1,3-cyclohexanediol, cis-1,2-cyclohexanediol, trans-1,3-cyclohexanedimethanol, or trans-1,4- ( 1-
Methyl) cyclohexanediol, trans-1,4-
Examples thereof include alkyl-, alkoxy- or halogen-substituted compounds of the alicyclic diols such as (1-chloro) cyclohexanediol.

Aliphatic diols include ethylene glycol and 1,3-
Examples thereof include linear or branched aliphatic diols such as propanediol, 1,4-butanediol and neopentyl glycol.

As aromatic hydroxycarboxylic acid, 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-
Aromatic hydroxycarboxylic acids such as 2-naphthoic acid and 6-hydroxy-1-naphthoic acid, or 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, 3-chloro-4-hydroxybenzoic acid, 2-chloro-4-hydroxybenzoic acid, 2,3-dichloro-4-hydroxybenzoic acid Acid, 3,5-dichloro-4
-Hydroxybenzoic acid, 2,5-dichloro-4-hydroxybenzoic acid, 3-bromo-4-hydroxybenzoic acid, 6
Alkyl and alkoxy of aromatic hydroxycarboxylic acid such as -hydroxy-5-chloro-2-naphthoic acid, 6-hydroxy-7-chloro-2-naphthoic acid and 6-hydroxy-5,7-dichloro-2-naphthoic acid Another example is a halogen-substituted product.

As the aromatic mercaptocarboxylic acid, 4-mercaptobenzoic acid, 3-mercaptobenzoic acid, 6-mercapto-
Examples thereof include 2-naphthoic acid and 7-mercapto-2-naphthoic acid.

Examples of aromatic dithiols include benzene-1,4-dithiol, benzene-1,3-dithiol, 2,6-naphthalene-dithiol, and 2,7-naphthalene-dithiol.

Examples of the aromatic mercaptophenol include 4-mercaptophenol, 3-mercaptophenol, 6-mercaptophenol and 7-mercaptophenol.

4- as aromatic hydroxy amine and aromatic diamine
Aminophenol, N-methyl-4-aminophenol, 1,4-phenylenediamine, N-methyl-1,4-phenylenediamine, N, N'-dimethyl-1,4-phenylenediamine, 3-aminophenol, 3 -Methyl-4-aminophenol, 2-chloro-4-aminophenol, 4
-Amino-1-naphthol, 4-amino-4'-hydroxydiphenyl, 4-amino-4'-hydroxydiphenyl ether, 4-amino-4'-hydroxydiphenylmethane, 4-amino-4'-hydroxydiphenylsulfide, 4, 4'-diaminophenyl sulfide (thiodianiline), 4,4'-diaminodiphenyl sulfone,
2,5-diaminotoluene, 4,4′-ethylenedianiline,
4,4'-diaminodiphenoxyethane, 4,4'-diaminodiphenylmethane (methylenedianiline), 4,4'-diaminodiphenylether (oxydianiline) and the like can be mentioned.

The polymers I) to VIII) composed of the above components may or may not form an anisotropic melt phase depending on the composition ratio in the components, the polymer, and the sequence distribution, but they are used in the present invention. The polymers are limited to those forming an anisotropic melt phase among the above polymers.

Polyesters of I), II), III) and V which are polymers forming an anisotropic melt phase suitable for use in the present invention.
The polyesteramide of III) can be produced by various ester forming methods that allow organic monomer compounds having functional groups that form the required repeating units by condensation to react with each other. For example, the functional groups of these organic monomer compounds may be carboxylic acid groups, hydroxyl groups, ester groups, acyloxy groups, acid halides, amine groups and the like. The organic monomer compound can be reacted by a molten acidolysis method without the presence of a heat exchange fluid. In this method, the monomers are first heated together to form a molten solution of the reactants. As the reaction continues, solid polymer particles become suspended in the liquid.
Volatile by-products of the final stage of condensation (eg acetic acid or water)
A vacuum may be applied to facilitate removal of the.

Further, a slurry polymerization method can also be adopted to form a wholly aromatic polyester suitable for use in the present invention. In this way, the solid product is obtained in suspension in the heat exchange medium.

Whichever of the above melt acidolysis method and slurry polymerization method is adopted, the organic monomer reactant that induces a wholly aromatic polyester is in a modified form in which the hydroxyl group of such a monomer is esterified at room temperature (that is, a It can be subjected to the reaction (as an acyl ester). The lower acyl group preferably has about 2 to 4 carbon atoms. Preferably, the acetic acid ester of such an organic monomer reactant is subjected to the reaction.

Further, as typical examples of the catalyst which can be optionally used in either the molten acidolysis method or the slurry method, dialkyl tin oxide (eg, dibutyl tin oxide), diaryl tin oxide, titanium dioxide, antimony trioxide, alkoxy titanium silicate, titanium alkoxide. , Alkali and alkaline earth metal salts of carboxylic acids (eg zinc acetate), Lewis (eg BF ₃ ), hydrogen halides (eg HCl)
Gaseous acid catalysts such as The amount of catalyst used is generally about 0.001 to 1% by weight, especially about 0.01 to 0.2% by weight, based on the total weight of the monomers.

The wholly aromatic polymers suitable for use in the present invention tend to be substantially insoluble in common solvents and therefore unsuitable for solution processing. However, as already mentioned, these polymers can be easily processed by conventional melt processing methods. Particularly preferred wholly aromatic polymers are somewhat soluble in pentafluorophenol.

The wholly aromatic polyesters suitable for use in the present invention generally have a weight average molecular weight of about 2,000 to 200,000, preferably about
It is 10,000 to 50,000, particularly preferably about 20,000 to 25,000. On the other hand, suitable wholly aromatic polyesteramides generally have a molecular weight of about 5,000 to 50,000, preferably about 10,000 to 30,
000, for example 15,000 to 17,000. The measurement of such a molecular weight can be carried out by a standard measurement method which does not involve solution formation of gel permeation chromatography and other polymers, for example, by quantifying an end group by infrared spectroscopy on a compression molded film. The molecular weight can also be measured by using a pentafluorophenol solution and using a light scattering method.

The above fully aromatic polyesters and polyesteramides also have an inherent viscosity (IV) of at least about 2.0 dl / g, for example about 2.0 to 10.0 dl / g when dissolved in pentafluorophenol at a concentration of 0.1% by weight at 60 ° C. Is generally indicated.

The polymer exhibiting an anisotropic melt phase used in the present invention is preferably an aromatic polyester and an aromatic polyesteramide, and also preferably a polyester partially containing the aromatic polyester and the aromatic polyesteramide in the same molecular chain. Polyester partially contained in is also a preferred example.

Preferred examples of compounds constituting them are 2,6-naphthalenedicarboxylic acid, 2,6-dihydroxynaphthalene and 1,4
-Naphthalene compounds such as dihydroxynaphthalene and 6-hydroxy-2-naphthoic acid, biphenyl compounds such as 4,4'-diphenyldicarboxylic acid and 4,4'-dihydroxybiphenyl, the following general formulas (I), (II) or ( III)
Compound represented by: (However, X: alkylene (C _{1 to} C ₄ ), alkylidene, -O
-, - SO -, - SO 2 -, - S -, - CO- than group selected _{Y :-( CH 2) n- (n} = 1~4), - O (CH 2) nO- (n
= 1 to 4)) p-hydroxybenzoic acid, terephthalic acid, hydroquinone, para-substituted benzene compounds such as p-aminophenol and p-phenylenediamine, and their nucleus-substituted benzene compounds (substituents are chlorine). , Bromine, methyl, phenyl, 1-phenylethyl), isophthalic acid, resorcin, and other meta-substituted benzene compounds.

A preferable example of the polyester partially containing the above-mentioned constituents in the same molecular chain is polyalkylene terephthalate, and the alkyl group has 2 to 4 carbon atoms.

Among the above-mentioned constituents, a compound containing one or more kinds of compounds selected from naphthalene compounds, biphenyl compounds and para-substituted benzene compounds as essential constituents is a further preferable example. Of the p-position-substituted benzene compounds, p-hydroxybenzoic acid, methylhydroquinone and 1-phenylethylhydroquinone are particularly preferable examples.

The following are exemplified as specific combinations of constituent components.

In the formula, Z is a substituent selected from —Cl, —Br, and —CH ₃ ,
X is alkylene (C ₁ ~C _4), alkylidene, -O -, -
_{SO -, - SO 2 -,} - S -, - it is a substituent selected from CO-.

Particularly preferred anisotropic melt phase forming polyesters for use in the present invention include repeating units containing naphthalene moieties such as 6-hydroxy-2-naphthoyl, 2,6-dihydroxynaphthalene and 2,6-dicarboxynaphthalene. It is contained in an amount of about 10 mol% or more. Preferred polyesteramides are those containing repeating units of the above-mentioned naphthalene moieties and moieties consisting of 4-aminophenol or 1,4-phenylenediamine. Specifically, it is as follows.

(1) A polyester consisting essentially of the following repeating units I and II.

This polyester contains about 10-90 mole% of Unit I and about 10-90.
It contains mol% of unit II. In one aspect unit I is about
It is present up to an amount of 65 to 85 mol%, preferably about 70 to 80 mol% (eg about 75 mol%). In another embodiment, the units II are present in much lower concentrations of about 15-35 mol%, preferably about 20-30 mol%. Further, at least some of the hydrogen atoms bonded to the ring are optionally selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and combinations thereof. It may be substituted with a selected substituent.

(2) A polyester consisting essentially of the following repeating units I, II and III.

This polyester contains about 30 to 70 mol% of Unit I. The polyester is preferably about 40-60 mol%
Unit I, about 20 to 30 mol% of unit II, and about 20 to 30 mol% of unit III. Moreover, at least a part of the hydrogen atoms bonded to the ring may have 1 to 4 carbon atoms.
May be substituted with a substituent selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and combinations thereof.

(3) A polyester consisting essentially of the following repeating units I, II, III and IV: (In the formula, R means methyl, chloro, bromo or a combination thereof, and is a substituent for a hydrogen atom on the aromatic ring), and the unit I is about 20 to 60 mol%,
II in amounts of about 5 to 18 mol%, unit III in amounts of about 5 to 35 mol%, and unit IV in amounts of about 20 to 40 mol%. The polyester is preferably about 35-45 mole% of Unit I, about 10
Containing ~ 15 mol% Unit II, about 15-25 mol% Unit III, and about 25-35 mol% Unit IV. However, unit II
The total molarity of and III is substantially equal to the molarity of unit IV. In addition, at least a part of the hydrogen atoms bonded to the ring may be a group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and a combination thereof. It may be substituted with a substituent selected from This wholly aromatic polyester has 0.3w of pentafluorophenol at 60 ℃.
at least 2.0 dl / g when dissolved at a concentration of / v% eg
Logarithmic viscosities of 2.0 to 10.0 dl / g are generally indicated.

(4) A polyester consisting essentially of the following repeating units I, II, III and IV: III General formula O-Ar-O (wherein Ar is at least 1
A dioxyaryl unit having a number of aromatic rings, IV. (Wherein Ar ′ means a divalent group containing at least one aromatic ring), and the unit I is about 20 to 40 mol% and the unit II is 10 mol%. Above 50 mol%, unit III above 5 mol% and below about 30 mol% and unit IV above 5 mol%,
It is contained in an amount of about 30 mol% or less. This polyester is
Preferably, about 20-30 mol% (eg, about 25 mol%) of unit I, about 25-40 mol% (eg, about 35 mol%) of unit II, about 15
~ 25 mol% (eg, about 20 mol%) of unit III, and about 15
Contains ~ 25 mol% (eg, about 20 mol%) of unit IV. In addition, at least a part of the hydrogen atoms bonded to the ring may be a group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and a combination thereof. It may be substituted with a substituent selected from

Units III and IV have symmetrically arranged divalent bonds on one or more aromatic rings that connect these units to other units on either side within the polymer backbone (eg, on a naphthalene ring). When present, they are preferably symmetrical with respect to each other in the para position or arranged on a diagonal ring). However, asymmetric units such as those derived from resorcinol and isophthalic acid can also be used.

Preferred dioxyaryl units III are And a preferred dicarboxyaryl unit IV is Is.

(5) A polyester consisting essentially of the following repeating units I, II and III: II A dioxyaryl unit represented by the general formula O-Ar-O (wherein Ar represents a divalent group containing at least one aromatic ring), (Wherein Ar ′ means a divalent group containing at least one aromatic ring), and the unit I is about 10 to 90 mol% and the unit II is 5 to 5 mol%.
45 mol%, containing unit III in an amount of 5-45 mol%. The polyester preferably contains about 20-80 mol% Unit I, about 10-40 mol% Unit II, and about 10-40 mol% Unit III. More preferably, the polyester comprises about 60-80 mol% units I, about 10-20 mol% units.
II, and about 10-20 mol% of unit III. In addition, at least a part of the hydrogen atoms bonded to the ring may be a group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and a combination thereof. It may be substituted with a substituent selected from

Preferred dioxyaryl units II are And a preferred dicarboxyaryl unit III is Is.

(6) Polyesteramide consisting essentially of the following repeating units I, II, III and IV: (In the formula, A means a divalent group containing at least one aromatic ring or a divalent trans-cyclohexane group), III General formula Y-Ar-Z (wherein Ar is at least 1)
A divalent group containing one aromatic ring, Y means O, NH or NR, Z means NH or NR, respectively, and R means an alkyl group having 1 to 6 carbon atoms or an aryl group), IV in general Of the formula O-Ar'-O (wherein Ar 'means a divalent group containing at least one aromatic ring), and the unit I is about 10 to 90 mol% and the unit II is about 5
~ 45 mol%, about 5-45 mol% unit III, and unit IV
In an amount of about 0 to 40 mol%. In addition, at least a part of the hydrogen atoms bonded to the ring may be a group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and a combination thereof. It may be substituted with a substituent selected from

Preferred dicarboxyaryl units II are And the preferred unit III is And a preferred dioxyaryl unit IV is Is.

Further, the polymer forming the anisotropic molten phase of the present invention,
A part of one polymer chain is composed of the polymer segment forming the anisotropic melt phase described above, and the remaining part is composed of the thermoplastic resin segment not forming the anisotropic melt phase. Polymers are also included.

The above-mentioned liquid crystalline polymer is a high-strength material in combination with the self-reinforcing effect, and has a small coefficient of linear expansion and a small molding shrinkage ratio, so that there is little dimensional deviation. It has low melt viscosity and good flowability, but it can withstand high temperatures of 180-200 ℃. It has good chemical resistance, weather resistance, and hot water resistance, is chemically extremely inert, and at the same time does not affect other substances.

In order to further improve the performance of the pump impeller of the present invention, these liquid crystalline polymers may further contain various inorganic fillers depending on the purpose. Examples of the inorganic substance include substances added to general thermoplastic resins and thermosetting resins, that is, general inorganic fibers such as glass fiber, carbon fiber, metal fiber, ceramic fiber, boron fiber, potassium titanate fiber, and asbestos. , Calcium carbonate, highly dispersible silicate, alumina, aluminum hydroxide, talc, mica, glass flakes, glass beads,
Quartz powder, silica sand, wollastonite, various metal powders, carbon black, barium sulfate, calcined gypsum and other powder substances, and silicon carbide, alumina, boron nitrite, silicon nitride and other powdered and plate-like inorganic compounds , Whiskers and metal whiskers are included.

These inorganic fillers may be used alone or in combination of two or more.

Further, the amount of these fillers to be blended is preferably 70% by weight or less based on the entire mixture with the resin from the viewpoint of moldability and the like.

Further, known substances added to general thermoplastic resins and thermosetting resins, that is, plasticizers, stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, flame retardants, coloring of dyes and pigments, etc. Agents, lubricants for improving fluidity and releasability, lubricants, crystallization accelerators (nucleating agents) and the like can be appropriately used according to required performance.

When molding the pump impeller, it can be molded using a normal injection molding machine. Although there is no particular point to note, in order to reduce the linear expansion and contraction rate, the radial direction is set to the center gate in the flow direction, or the number of symmetrically arranged gates greatly improves dimensional stability. . There are various types of regenerative pump impellers, but there is no particular limitation, and any type can be molded.

〔The invention's effect〕

Since the present invention has the above-mentioned configuration, it goes without saying that it has the effects of being rust-resistant and lightweight, which is an object of general plastics.

In addition, the use of the liquid crystalline polymer has the following unique effects.

(1) The liquid crystal polymer has excellent fluidity and small molding shrinkage, which enables precision molding, does not require a step of finishing to a predetermined dimension by cutting, and has excellent workability.

(2) Due to the high strength of the liquid crystalline polymer, it will not be damaged during use.

(3) The liquid crystalline polymer has a small linear expansion coefficient, and the discharge capacity is unlikely to change due to the change in the gap due to the temperature change during use.

(4) The liquid crystalline polymer is excellent in chemical resistance and, in combination with the above properties, is suitable for an impeller such as a fuel pump of an automobile.

〔Example〕

The present invention will be further described with reference to examples, but the present invention is not limited thereto.

Reference Example 1 (Polymer A) 4-acetoxybenzoic acid 1081 parts by weight, 6-acetoxy-
2-naphthoic acid 460 parts by weight, isophthalic acid 166 parts by weight, 1,
194 parts by weight of 4-diacetoxybenzene was charged into a reactor equipped with a stirrer, a nitrogen introducing tube and a distilling tube, and the mixture was heated to 260 ° C under a nitrogen stream. While distilling acetic acid from the reactor, the mixture was vigorously stirred at 260 ° C. for 2.5 hours and then at 280 ° C. for 3 hours. Furthermore, after raising the temperature to 320 ° C. and stopping the introduction of nitrogen, the pressure inside the reactor was gradually reduced and after 15 minutes the pressure was lowered to 0.1 mmHg, and stirring was carried out at this temperature and pressure for 1 hour.

The polymer obtained had an inherent unit of 5.0, measured in pentafluorophenol at a concentration of 0.1% by weight at 60 ° C.

This polymer has the following structural units.

Reference Example 2 (Polymer B) 1081 parts by weight of 4-acetoxybenzoic acid, 489 parts by weight of 2,6-diacetoxynaphthalene, and 332 parts by weight of terephthalic acid were placed in a reactor equipped with a stirrer, a nitrogen introducing pipe and a distilling pipe. Preparation,
The mixture was heated to 250 ° C under a stream of nitrogen. While distilling acetic acid from the reactor, at 250 ° C for 2 hours, then at 280 ° C.
Stir vigorously for 2.5 hours. Furthermore, after raising the temperature to 320 ° C and stopping the introduction of nitrogen, the pressure inside the reactor was gradually reduced and after 30 minutes the pressure was lowered to 0.2 mmHg, and at this temperature and pressure 1.5
Stir for hours.

The polymer obtained had an inherent viscosity of 2.5, measured in pentafluorophenol at a concentration of 0.1% by weight and at 60 ° C.

This polymer has the following structural units.

Reference example 3 (Polymer C) 4-acetoxybenzoic acid 1261 parts by weight, 6-acetoxy-
691 parts by weight of 2-naphthoic acid was charged into a reactor equipped with a stirrer, a nitrogen introducing tube and a distilling tube, and the mixture was heated to 250 ° C under a nitrogen stream. While distilling acetic acid from the reactor, the mixture was vigorously stirred at 250 ° C. for 3 hours and then at 280 ° C. for 2 hours. Furthermore, after raising the temperature to 320 ° C and stopping the introduction of nitrogen, the pressure inside the reactor was gradually reduced and after 20 minutes the pressure was reduced to 0.1 m.
The pressure was lowered to mHg, and the mixture was stirred at this temperature and pressure for 1 hour.

The polymer obtained had an inherent viscosity of 5.4 measured in pentafluorophenol at a concentration of 0.1% by weight at 60 ° C.

This polymer has the following structural units.

Reference Example 4 (Polymer D) 1612 parts by weight of 6-acetoxy-2-naphthoic acid, 290 parts by weight of 4-acetoxyacetanilide, 249 parts by weight of terephthalic acid, 0.4 parts by weight of sodium acetate were added to a stirrer, a nitrogen introducing pipe and a distilling pipe. The reactor was charged and the mixture was heated to 250 ° C under a stream of nitrogen. While distilling acetic acid from the reactor, the mixture was vigorously stirred at 250 ° C. for 1 hour and then at 300 ° C. for 3 hours. Furthermore, after raising the temperature to 340 ° C. and stopping the introduction of nitrogen, the pressure was gradually reduced in the reactor and the pressure was reduced to 0 after 30 minutes.
It was lowered to 2 mmHg and stirred at this temperature and pressure for 30 minutes.

The polymer obtained had an inherent viscosity of 3.9 as measured in pentafluorophenol at a concentration of 0.1% by weight at 60 ° C.

This polymer has the following structural units.

Reference Example 5 (Polymer E) 768 parts by weight of polyethylene terephthalate having an intrinsic viscosity of 0.62 and 1080 parts by weight of p-acetoxybenzoic acid were charged into a reactor equipped with a stirrer, a nitrogen introducing tube and a distilling tube, and 240 ° C. under a nitrogen stream. Heated to. Raise the temperature to 275 ° C over 1 hour,
Stir vigorously for 1 hour. Next, after the introduction of nitrogen was stopped, the pressure inside the reactor was gradually reduced and after 30 minutes the pressure was reduced to 0.4 mmHg.
And further stirred for 4 hours.

The polymer obtained had an intrinsic viscosity of 0.66 measured in pentafluorophenol at a concentration of 0.1% by weight at 60 ° C. and exhibited optical anisotropy when melted.

This polymer mainly has the following constitutional units.

Example 1 and Comparative Example 1 A pump impeller of the present invention as injection-molded from the polymers (polymers A to E) obtained in Reference Examples 1 to 5 and a known phenolic resin finished to a predetermined size by cutting after compression molding. The surface roughness (average) of the impeller-side flat surface of the impeller is measured and is as shown in Table 1.

It can be seen that the molding accuracy of the product of the present invention made of a liquid crystal polymer is equal to or slightly superior to the phenol resin product obtained by cutting.

Example 2 and Comparative Example 2 Sample 1; Resin composition made of polymer C only Sample 2; Polymer C 100 parts by weight Resin composition made of 30 parts by weight Glass fiber Sample 3; Polymer C 100 parts by weight Glass fiber 25 parts by weight Part A 50 mm diameter automobile fuel pump impeller made of a resin composition consisting of 25 parts by weight of carbon fiber was used at 300 ° C.
Made by injection molding with 60 parts by weight of toluene, isooctane
It was immersed in 40 parts by weight at 60 ° C. for 720 hours, and the gasoline resistance was measured. The results are shown in Table 2.

As Comparative Example 2, Sample 4; a pump impeller made of phenolic resin was prepared in the same manner as in Example 2, and the same measurement results are shown in Table 2.

Example 3 and Comparative Example 3 Pump impellers having a diameter of 40 mm were prepared from samples 1, 2, 3 and 4 used in Example 2 and Comparative Example 2 by injection molding at 300 ° C., and were gasoline resistant in the same manner as in Example 2. Was tested. In addition, water resistance was tested by immersing in water at room temperature for 1000 hours. The results are shown in Table 3.

Example 4 A pump impeller was manufactured by injection molding in the same manner as in Example 3 except that the polymer (Polymer A) obtained in Reference Example 1 was used.
The gasoline resistance was tested in the same manner as in Example 2 and the water resistance was tested in the same manner as in Example 3, and the results in Table 4 were obtained.

Sample 1; made of a resin composition consisting only of polymer A Sample 2; made of a resin composition consisting of 100 parts by weight of polymer A 30 parts by weight of glass fiber Example 5 A pump impeller was produced by injection molding in the same manner as in Example 3 except that the polymer (Polymer B) obtained in Reference Example 2 was used instead of Polymer C, and gasoline resistance was obtained in the same manner as in Example 2. The water resistance was tested in the same manner as in Example 3, and the results shown in Table 5 were obtained.

Sample 1; made of a resin composition consisting only of polymer B Sample 2; made of a resin composition consisting of 100 parts by weight of polymer B 30 parts by weight of glass fiber Example 6 A pump impeller was produced by injection molding in the same manner as in Example 3 except that the polymer (Polymer D) obtained in Reference Example 4 was used in place of Polymer C, and gasoline resistance was obtained in the same manner as in Example 2. The water resistance was tested in the same manner as in Example 3, and the results shown in Table 6 were obtained.

Sample 1; made of a resin composition consisting only of polymer D Sample 2; made of a resin composition consisting of 100 parts by weight of polymer D 30 parts by weight of glass fiber Example 7 A pump impeller was produced by injection molding in the same manner as in Example 3 except that the polymer (Polymer E) obtained in Reference Example 5 was used instead of Polymer C, and gasoline resistance was obtained in the same manner as in Example 2. The water resistance was tested in the same manner as in Example 3, and the results shown in Table 7 were obtained.

Sample 1; Resin composition made of polymer E only Sample 2; Polymer E 100 parts by weight Resin composition made of 30 parts by weight glass fiber

[Brief description of drawings]

FIG. 1 is a schematic side sectional view of a regenerative pump, FIG. 2 is a schematic cutaway sectional view of the same front portion, FIG. 3 is an enlarged view of an upper portion of an impeller of FIG. 2, and FIG. 4 is IV of FIG. 4 is a schematic cross-sectional view taken along line IV-IV. 1 ... Pump impeller 2 ... Casing 3 ... Fan-shaped groove 4 ... Flow path

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Claims (2)

[Claims] 1. A melt-processable polymer capable of forming an anisotropic melt phase, which is injection-molded with a gate position provided at the center of the molded product or at a symmetrical position with respect to the center of the molded product. A pump impeller characterized by. 2. A pump impeller according to claim 1, wherein the pump impeller is for automobile fuel.