JP2620541B2 - Thermoplastic polyester resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermoplastic polyester resin composition having extremely excellent short-term and long-term friction and wear characteristics and capable of providing a sliding part having low frictional noise during sliding. More specifically, a thermoplastic polyester resin obtained by blending (A) a thermoplastic polyester resin with (B) a silicone oil having a viscosity of 150,000 cSt (centistokes) or more and (C) a lubricating oil having a viscosity of 3,000 cSt or less. It relates to a composition.

[0002]

2. Description of the Related Art Thermoplastic polyester resins such as polybutylene terephthalate and polyethylene terephthalate are excellent in mechanical properties, electrical properties, heat resistance, chemical resistance and the like, and have good workability. Because of its good properties, it has recently been used in an extremely wide field as an engineering resin. With the expansion of the field of use, these resins tend to be used under more severe conditions, and there is an increasing need for resins to have higher properties. As one of such properties, in the fields of sliding parts such as automobiles, electric and electronic products, mechanical parts, etc., further improvement of friction and wear characteristics and long-term sustainability or frictional noise caused by sliding. Reduction may be required. Conventionally, as a method of improving the friction and wear characteristics of a thermoplastic resin, for example, (1) a method of adding a solid lubricant such as molybdenum disulfide, graphite, (2)
Known methods include adding powder or fiber of polytetrafluoroethylene resin, (3) adding a liquid or semi-solid lubricant such as petroleum-based lubricating oil, synthetic lubricating oil, aliphatic alcohol or its ester, etc. I have. Even with these methods conventionally known, the friction and wear characteristics are of course improved, and in particular, in short-term use under low-speed, low-load sliding conditions, it can often sufficiently satisfy the demand, As the sliding conditions of high speed and high load become, the friction characteristics become insufficient.
Even at a low speed and a low load, there is a problem that the frictional characteristics are greatly reduced as the sliding time elapses, and the long-term stability and reliability are lacking. As a method of improving frictional noise during sliding, a method of blending polyethylene, polytetrafluoroethylene, or the like is generally used. However, noise reduction that can meet the demand cannot be always obtained, and mechanical strength and the like are not obtained. However, there is a problem that the physical properties of the material deteriorate. As described above, in the conventionally known methods, the friction and wear characteristics, particularly the characteristics under high speed and high load conditions,
Or, in terms of long-term characteristics and noise reduction characteristics at the time of sliding, it is not possible to meet strict requirements, and there is a strong demand for improvement.

[0003]

Means for Solving the Problems The present inventors have solved the above problems and have improved short-term and long-term friction and wear characteristics without impairing the excellent physical properties inherent in thermoplastic polyester resins, and As a result of intensive studies on methods to reduce the frictional noise during sliding, the combination of a specific high-viscosity silicone oil and a specific low-viscosity lubricating oil produces a synergistic effect. The present inventors have found that the characteristics of the present invention are dramatically improved, and have reached the present invention.
That is, the present invention (A) thermoplastic polyester resin 99.9 ~
60.0 parts by weight of (B) a silicone oil having a viscosity of 150,000 cSt (centistokes) or more and 0.05-20.0 parts by weight
(C) A thermoplastic resin composition comprising 0.05 to 20.0 parts by weight of a lubricating oil having a viscosity of 3,000 cSt (centistokes) or less.

[0004]

DETAILED DESCRIPTION OF THE INVENTION The thermoplastic polyester used in the present invention is a polyester obtained by polycondensation of a dicarboxylic acid compound and a dihydroxy compound, polycondensation of an oxycarboxylic acid compound, or polycondensation of a mixture of these three components. The present invention is effective for any of polyester, homopolyester and copolyester. Examples of dicarboxylic acid compounds used here include known dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, and sebacic acid. Acid compounds and their alkyl, alkoxy or halogen substituents. In addition, these dicarboxylic acid compounds can be used in the form of a derivative capable of forming an ester, for example, a lower alcohol ester such as dimethyl ester.
In the present invention, one or more of the above compounds are used. Next, examples of dihydroxy compounds include ethylene glycol, propylene glycol, butanediol, neopentyl glycol, polyoxyalkylene glycol, hydroquinone, resorcinol, dihydroxyphenyl, naphthalene diol, dihydroxydiphenyl ether, cyclohexanediol, and 2,2′-.
Dihydroxy compounds such as bis (4-hydroxyphenyl) propane and their alkyl, alkoxy or halogen-substituted compounds, and the like, and one or more kinds thereof can be used in combination. Examples of oxycarboxylic acids include oxycarboxylic acids such as oxybenzoic acid, oxynaphthoic acid, and diphenyleneoxycarboxylic acid, and alkyl, alkoxy or halogen-substituted products thereof.
Further, derivatives of these compounds capable of forming an ester can also be used. In the present invention, one or two of these compounds
More than one species is used. In the present invention, any of the thermoplastic polyesters produced by polycondensation using the compound as a monomer component as described above can be used, and they can be used alone or as a mixture of two or more kinds. Preferably, polyalkylene terephthalate is used. More preferably, polybutylene terephthalate is used, and the effect of the present invention is remarkable. In the present invention, the thermoplastic polyester may be modified by a known method such as crosslinking or graft polymerization.

[0005] Next, in the present invention, the silicone oil (component B) to be blended with the thermoplastic polyester resin (component A) as described above is dimethylpolysiloxane or a methyl group of which is partially hydrogen, phenyl group, halogenated ASTM D-445 substituted with one or more of a phenyl group, a halogenated alkyl group, a fluoroester group and the like.
Having an extremely high viscosity of 150,000 cSt (25 ° C.) or more as measured by the method described above. By blending a silicone oil with a lower viscosity than this, especially a silicone oil of 100,000 cSt or less, the initial friction and wear characteristics are improved, but the long-term friction and wear characteristics or the friction noise during sliding, which is the object of the present invention, is sufficiently improved. On the other hand, it is extremely difficult to uniformly disperse the rubber-like silicone resin in the resin with a high degree of polymerization. It is not preferable because it may be damaged. More preferably, 200,000 to 1,00
One having a viscosity of 0,000 cSt is used. In the present invention, such a high-viscosity silicone oil can be diluted with a solvent or the like, or can be added by adsorbing to an inorganic or organic solid, thereby improving the workability of adding the silicone oil or the dispersibility of the silicone oil. Is often preferred from the viewpoint of It is also preferable to use a dispersant in combination to improve the dispersion of the silicone oil in the resin.

In the present invention, the high viscosity silicone oil (component B) is used in combination, and the component C is 3,000 or more.
A lubricating oil having a viscosity of 0 cSt (25 ° C.) or less is blended, whereby a synergistic effect is exhibited, and the friction and wear characteristics are dramatically improved both in a short term and in a long term. In order to more effectively bring out a synergistic effect, a lubricating oil having a viscosity of 2,000 cSt or less is preferable. The lubricating oil (component (C)) used in the present invention is a known lubricating oil such as a synthetic lubricating oil, a petroleum-based lubricating oil, an animal or vegetable oil, and one or more selected from these groups are added. You. Here, petroleum-based lubricating oils are petroleum fractionated, paraffinic oils obtained by refining,
It is an oil whose main component is a hydrocarbon such as naphthene,
Examples include turbine oil, machine oil, engine oil, gear oil, spindle oil, refrigerator oil, paraffin oil, and the like. Examples of the synthetic lubricating oil include various silicone oils, polyalkylene glycol oils, polyol ester oils, polyphenyl ether oils, diester oils, and polyolefin oils. In addition, animal and plant oils are oils collected from plant fruits, seeds, animal fats, and the like. Squalene and the like, and higher fatty acids and their esters, which are the main constituents of these animal and vegetable oils, whether they are natural or synthetic, have a viscosity requirement as a C component. Is included in the lubricating oil of the present invention. The lubricating oil (component C) of the present invention may contain an antioxidant, an extreme pressure agent, an antiwear agent, an oil agent, a viscosity index improver, a pour point depressant, etc. for the purpose of improving its properties. Further, it may be in the form of a grease to which a thickener or the like has been added, or may have a diluent or the like. The point is that the base oil should satisfy the requirements of the present invention. In the present invention, among such lubricants, petroleum-based lubricating oils, particularly paraffinic oils, are preferable, and silicone oils, which are synthetic lubricating oils, are also preferable.

In the present invention, the addition amount of the high-viscosity silicone oil (component B) and the low-viscosity lubricating oil (component C) as described above is 0.05 to 0.05 parts by weight with respect to 99.9 to 60 parts by weight of the thermoplastic resin (component A). ~ 20 parts by weight. If the amount is smaller than this, a remarkable improvement in friction and wear characteristics due to a synergistic effect cannot be obtained. Conversely, if the amount is excessive, not only the workability is significantly impaired but also a large decrease in mechanical properties and the like may be caused, which is not preferable. . Therefore, in consideration of these physical properties, it is preferable that each of the high-viscosity silicone oil (component B) and the low-viscosity lubricating oil (component C) be blended in the range of 0.2 to 10 parts by weight. In order to more effectively bring out a synergistic effect on the improvement of the friction and wear characteristics, the ratio of the low-viscosity lubricating oil (component C) / the high-viscosity silicone oil (component B) is preferably 1/5 to 5/1.

The reason why the synergistic effect is exhibited by the combined use of the high-viscosity silicone oil and the low-viscosity lubricating oil in the present invention and the short-term and long-term friction and wear properties are remarkably improved is not necessarily clear, but the present inventors speculate. According to places, in the combination system, a high-viscosity silicone oil forms a stable film that does not easily peel off on or near the resin surface, bleeds out easily under normal conditions, and is insufficient in terms of long-term properties Low viscosity lubricating oil is stably retained in this coating,
Therefore, it is considered that the excellent friction characteristics of the low-viscosity lubricating oil are maintained not only for a short period but also for an extremely long period.

In the composition of the present invention, a solid lubricant such as graphite, molybdenum disulfide and metal soap, a good lubricating property such as a polyethylene resin and a polytetrafluoroethylene resin are used for the purpose of further improving the sliding properties. A polymer or the like that can be imparted can also be blended. Further, according to the purpose, in order to improve the physical properties, various known additives may be further blended. Examples of additives include antioxidants, weather and light resistance stabilizers, heat stabilizers, lubricants, release agents, nucleating agents, silicone oil dispersants, antistatic agents, flame retardants, colorants, and the like. In addition, the composition of the present invention can be added with a fibrous, plate-like, or granular inorganic filler such as glass fiber according to the purpose. It is of course possible to do so.

The composition of the present invention is easily prepared by a known method generally used as a conventional resin composition preparation method. For example, after mixing each component, kneading and extruding with a single-screw or twin-screw extruder to prepare pellets, and thereafter, a method of molding, once preparing pellets having a different composition, and mixing a predetermined amount of the pellets To obtain a molded product of the desired composition after molding,
Alternatively, any method such as a method of directly charging two or more can be used. In particular, a high-viscosity silicone oil (component B) and a low-viscosity lubricating oil (component C) are preliminarily mixed and then mixed with a resin (component A).
Is preferable in terms of workability because the lubricant (B and C components) can be easily handled.

[0011]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Examples 1 to 9 and Comparative Examples 1 to 6 A polybutylene terephthalate resin (trade name “Duranex 2000” manufactured by Polyplastics Co., Ltd.) and a silicone oil having a viscosity of 150,000 cSt or more as shown in Table 1 were used.
Various lubricating oils of 3,000 cSt or less were mixed at a ratio shown in Table 1, and then melt-kneaded with a twin-screw extruder to prepare a pellet-shaped composition. Next, a test piece was prepared from the pellet by injection molding and evaluated. Further, for comparison, as shown in Table 2, those in which neither the high-viscosity silicone oil nor the low-viscosity lubricating oil was added, those in which only one of them was added, and the like were similarly evaluated. The results are shown in Tables 1 and 2. The sliding characteristics were evaluated by the following method, and the tensile characteristics were measured according to the ASTM measurement method.

Dynamic friction characteristics Using a Suzuki type friction and wear tester, applied pressure 0.75 kg / cm ² , linear velocity 180 mm / sec, contact area 2.0 cm ² , mating material ABS resin,
The dynamic friction coefficient was measured immediately after the start of sliding and after sliding for a predetermined time.

Frictional sound characteristics Using the tester described above, a pressure of 3.5 kg / cm ² and a linear velocity of 50 mm / s
With ec, the contact area was 2.0 cm ² , the occurrence of squeak noise was evaluated while sliding the same kind of material for 10 hours.

[0014]

[Table 1]

[0015]

[Table 2]

[0016]

As is apparent from the above description and Examples, synergistic effects can be obtained by blending a thermoplastic polyester resin with a silicone oil having a viscosity of 150,000 cSt or more and a lubricating oil having a viscosity of 3,000 cSt or less. The effect is exhibited, and various characteristics relating to sliding such as short-term and long-term friction and wear characteristics, frictional noise during sliding, etc. are remarkably improved, and there is no inconvenience that other physical properties are substantially reduced. As described above, the composition of the present invention has well-balanced and excellent properties, and is a sliding member in the fields of automobiles, electric / electronic devices, office machines, miscellaneous goods, and the like, such as gears, bearings, and keyboards. It is suitably used as a part or the like.

Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C08L 91:06)

Claims (5)

(57) [Claims] (A) a thermoplastic polyester resin (99.9-6)
(B) 0.05 to 20.0 parts by weight of silicone oil having a viscosity of 150,000 cSt (centistokes) or more
(C) A thermoplastic polyester resin composition containing 0.05 to 20.0 parts by weight of a lubricating oil having a viscosity of 3,000 cSt (centistokes) or less. 2. The thermoplastic polyester resin composition according to claim 1, wherein the thermoplastic polyester resin is a polyalkylene terephthalate. 3. The thermoplastic polyester resin composition according to claim 1, wherein the thermoplastic polyester resin is polybutylene terephthalate. 4. The thermoplastic polyester resin composition according to claim 1, wherein the lubricating oil is a paraffinic oil. 5. The method according to claim 1, wherein the lubricating oil is a silicone oil.
4. The thermoplastic polyester resin composition according to any one of claims 1 to 3.