JPH0425562A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin compsn. which is excellent in toughness and sliding characteristics and generates a decreased amt. of flash in molding by compounding a polyphenylene sulfide resin having a limited flowability with a carbon fiber and, if necessary, a lubricant. CONSTITUTION:A resin comsn. is prepd. by compound 100 pts.wt. polyphenylene sulfide resin with 10-40 pts.wt. carbon fiber. The resin has a melt viscosity (eta) at 300 deg.C and a non-Newtonian index (n) satisfying the relationship 2.5 n-1.0<=logeta<=2.5n+0.3, 2.9<=logeta, and 1.1<=n<=1.6. Although the carbon fiber has a lubricating effect, 10-60 pts.wt carbon fiber and 1-20 pts.wt. lubricant (e.g. a fluororesin, molybdenum disulfide, or a silicone oil) are compounded into 100 pts.wt. said resin when the conditions of use require esp. excellent sliding characteristics.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a polyphenylene sulfide resin composition, and more specifically, it is composed of a polyphenylene sulfite resin exhibiting limited fluidity, carbon fiber, and a lubricating component. This invention relates to a resin composition.

Polyphenylene sulfide resin has excellent heat resistance,
Due to its chemical resistance, it is attracting attention as an electrical, electronic component, and automobile equipment component. Furthermore, it can be molded into various molded parts, films, sheets, fibers, etc. by injection molding, extrusion molding, etc., and is widely used in fields where heat resistance and chemical resistance are required.

[Prior Art] In recent years, due to the diversification of usage environments, there has been a demand for better properties for parts that were previously thought to be able to be satisfied with general-purpose engineering plastics.

For example, polyamide resin is widely used in place of metal for bearing cages due to its moldability, productivity, mechanical properties such as flexibility, and cost. However, under conditions of continuous use at high temperatures or constant or intermittent contact with chemicals such as oils and acids, the material deteriorates over time, making it difficult to meet the performance requirements of the market. I can't say that there is a gap.

In addition, polyacetal resin is widely used in place of metal for gears such as motor gears due to mechanical properties such as moldability, productivity, flexibility, self-lubricity, noise, and cost. However, due to the lighter weight and higher density of various parts, there are some cases where conventional physical properties cannot be used, such as the need to use plastic gears in high-temperature parts around the engine.

Although polyphenylene sulfide resin is known as a resin with excellent heat resistance and chemical resistance, the resin alone does not have sufficient strength and heat resistance. Therefore, polyphenylene sulfide resin can be strengthened by adding fibrous substances.
Used to increase heat resistance. However, when reinforcing with glass fiber, which is a typical example of a fibrous material, the strength is improved when the material is highly filled, but the sliding properties are degraded and wear of the mating material is caused. On the other hand, if the content of glass fiber is reduced in an attempt to improve sliding properties, the strength will decrease and the shape and usage environment of the product will be limited.

Generally, sliding properties are further improved by adding lubricating components such as fluororesin and silicone oil, but conversely, adding lubricating components reduces the strength of the product.

In addition, conventional cross-linked PPS could not be used for these parts because it lacked mechanical strength even when reinforcing materials were added, and its sliding properties deteriorated due to high filling.

In recent years, linear PPS has been developed, and taking advantage of its characteristic toughness, it has been published as
As disclosed in No. 3, it is used in various parts such as bearing retainers. However, linear PPS is cross-linked PPS
The disadvantage is that there are more Paris than . For example, in the case of bearing cages, the occurrence of sparks accelerates the wear of the rolling elements (steel balls), and in the case of gears, the surface roughness of the mating side decreases, resulting in contact noise and thickening. cause a phenomenon.

Therefore, it has not yet been possible to obtain a polyphenylene sulfide resin composition that has excellent mechanical strength, particularly toughness, sliding properties, and low occurrence of flaking.

[Problems to be Solved by the Invention] The present invention improves toughness and sliding properties by blending a specific amount of carbon fiber and, in some cases, a specific amount of a lubricating component, with a polyphenylene sulfide resin that exhibits limited fluidity. An object of the present invention is to provide a polyphenylene sulfide resin composition which is excellent and has suppressed spalling.

[Means for Solving the Problems] That is, the present invention provides a polyphenylene sulfide resin whose relationship between melt viscosity (η poise) and non-Newtonian index (n) measured at 300°C satisfies the following formula (%) for 100 parts by weight of polyphenylene sulfide resin. 10 to 40 parts by weight of a resin composition characterized by comprising carbon fibers and 100 parts by weight of a polyphenylene sulfide resin having the above-mentioned physical properties.
An object of the present invention is to provide a resin composition characterized by comprising ~60 parts by weight of carbon fiber and 1~20 parts by weight of a lubricating component.

The polyphenylene sulfide resin used in the present invention is
It can be produced by a method of reacting a dihalogenated aromatic compound and an alkali metal sulfide in an organic amide solvent.

The organic amide, dihalogenated aromatic compound, and alkali metal sulfide used here will be explained.

Organic amides include, for example, N,N-dimethylacetamide, N,N-dimethylformamide, hexamethylphosphoramide, N-methyl-ε-caprolactam, N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone. , tetramethylurea, 13-dimethylimidazolidinone, and mixtures thereof.

Dihalogenated aromatic compound means an aromatic compound having two halogen groups in one molecule, and includes, for example, p-dichlorobenzene, p-dibromobenzene, p-shortbenzene, and mixtures thereof. p-dichlorobenzene is preferred, with 90 mol% as a structural unit
It is more preferable to include the above. In addition, if it is less than 10 mol% as a structural unit, m-dichlorobenzene etc.
Dihalobenzene such as dihalobenzene and 0-dichlorobenzene, dichlornaphthalene, dibromonaphthalene, dichlordiphenyl sulfone, dichlorobenzophenone, dichlordiphenyl ether, dichlordiphenyl sulfide, dichlordiphenyl, dibromodiphenyl, dichlordiphenyl sulfoxide, etc. It is also possible to increase branching and/or crosslinking by copolymerizing dihaloaromatic compounds having three or more norogens in one molecule, without departing from the purpose of the present invention. It is.

In addition, as an alkali metal sulfide, lithium sulfide,
Mention may be made of sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and mixtures thereof, which may also be used in the form of hydrates. These alkali metal sulfides are prepared by reacting a hydrated alkali metal with an alkali metal base, or by reacting hydrogen sulfide with an alkali metal base, and are prepared on the spot prior to the addition of p-dihalobenzene into the polymerization system. It is also possible to use one prepared outside the system. Among the alkali metal sulfides mentioned above, sodium sulfide is preferred for use in the present invention.

In order to exhibit the effects of the present invention, it is necessary to use a polyphenylene sulfide resin having limited fluidity. Fluidity varies depending on the molecular weight and degree of crosslinking of the polyphenylene sulfide resin.

The molecular weight has a correlation with the melt viscosity (η), and the degree of crosslinking can be expressed by the non-Newtonian index (n).

(Here, the melt viscosity is 300°C, shear rate 200 (
This is a value measured under the following conditions: ) Also, the non-Newtonian index is defined by the following formula.

γ −□ τ 0 η (where γ is shear rate (sec-1), η is melt viscosity (poise), τ is shear stress (kg/cJ), and n is a non-Newtonian exponent.) Therefore, the present invention The limited fluidity of the polyarylene sulfide resin used in is due to the melt viscosity measured at 300°C:
It can be expressed by the following formula using η poise and non-Newtonian exponent; n.

(a) 2.5n-1,0≦l ogr)≦2.5n+0
．． 3 (b) 2.9≦logη (c) 1.1≦n≦1.6 If the melt viscosity 77 is too low, the strength of the molded product will be insufficient, and if it is too high, the fluidity will deteriorate and the moldability will deteriorate. A problem arises. In addition, if the non-Newtonian index "] is small, the occurrence of paris increases, and if this value becomes large, there is a problem that the liquidity deteriorates.

In the present invention, as a method for obtaining a borif-5-nylene sulfide resin having limited fluidity, the above-mentioned copolymerization or crosslinking of an aromatic compound having three or more halogens may be used. To achieve crosslinking, the PPS after polymerization may be heat treated (cured) at a temperature below its melting point, and by controlling the heating temperature, heating time, or concentration of oxygen present in the atmosphere, the desired It is possible to obtain a polyphenylene sulfide resin having fluidity of . Hereinafter, curing will be specifically explained.

The curing temperature is below the melting point of PPS, preferably 15
The temperature is preferably 0°C or higher and 270°C or lower.

The curing time is affected by temperature and atmosphere, but is preferably 5 minutes to 50 hours, preferably 30 minutes to 15 hours.

The raw material for carbon fibers may be either PAN-based or pitch-based, but pitch-based carbon fibers, which are generally said to have good sliding properties, are preferred. The length of the carbon fiber used in the present invention is 1 to 12 mm, preferably 3 to 5 mm before melting and mixing.
, and the fiber diameter is 2 to 20 μm, preferably 3 to 10
μm is good.

When the fiber length is less than 1 mm or the fiber diameter exceeds 20 μm, the reinforcing effect of the polyphenylene sulfide resin is small, and when the fiber length exceeds 12 mm or the fiber diameter is less than 2 μm, the resulting composition The moldability of the product may change.

The amount of carbon fiber added to the polyphenylene sulfide resin used in the present invention is 10 parts by weight per 100 parts by weight of the polyphenylene sulfide resin when no lubricating component is added.
-40 parts by weight, preferably 20-35 parts by weight. If the amount added is less than 10 parts by weight, the strength of the molded product
Heat resistance may not be sufficient, which is not preferable. On the other hand, 4
If it exceeds 0 parts by weight, the toughness may decrease, cracks may occur during molding or assembly, and sliding properties may deteriorate.

Carbon fiber itself has a lubricating effect, but depending on the usage environment,
When particularly excellent sliding properties are required, it is generally necessary to add a known lubricating component.

The lubricating components used in the present invention include fluororesins such as tetrafluoroethylene resin (PTFE), chlorotrifluoroethylene resin, vinyl fluoride resin, vinylidene fluoride resin, tetrafluoroethylene-pentafluoropropylene copolymer, etc. Examples include molybdenum sulfide and silicone oil. Among these, PT is generally known as a lubricating component and is easily available.
FE is suitable. A particle size of about 10 to 100 μm is easy to handle.

The content of lubricating components is 1 to 2 per 5100 parts by weight of PP.
It is within 0 parts by weight. This is because if it exceeds 20 parts by weight, strength and heat resistance will decrease. More preferably, it is within 15 parts by weight. At this time, the amount of carbon fiber added is 10 parts by weight per 100 parts by weight of polyphenylene sulfide resin.
It can be increased to ~60 parts by weight, preferably 20-45 parts by weight.

Further, other reinforcing materials, fillers, and resins may be blended without departing from the purpose of the present invention.

Examples of fibrous reinforcing agents other than carbon fiber include glass fiber,
Examples include alumina fibers, ceramic fibers, aramid fibers, wholly aromatic polyesters, metal fibers, potassium titanate whiskers, and the like.

Inorganic fillers and organic and inorganic pigments other than lubricating ingredients include:
For example, calcium carbonate, mica, talc, silica, barium sulfate, calcium sulfate, kaolin, clay, pyroferrite, bentonite, sericite, zeolite,
Nephelinsinite, attapulgite, wollastonite, ferrite, calcium silicate, magnesium carbonate, dolomite, antimony trioxide, zinc oxide, titanium oxide, titanium oxide, magnesium oxide, iron oxide, molybdenum disulfide, graphite, gypsum, glass beads , glass powder, glass balloon, quartz, quartz glass, etc.

In addition, without departing from the gist of the present invention, mold release agents such as aromatic hydroxy derivatives, silane-based and titanate-based coupling agents, heat-resistant stabilizers, weather-resistant stabilizers, crystal nucleating agents,
Foaming agents, rust preventives, ion trapping agents, flame retardants, flame retardant aids, etc. may be added.

In addition, polyethylene, polypropylene,
polybutadiene, polyisoprene, polychloroprene,
polystyrene, polybutene, polyα-methylstyrene,
Poamides such as polyvinyl acetate, polyvinyl chloride, polyacrylic ester, polymethacrylic ester, polyacrylonitrile, nylon 6, nylon 66, nylon 610, nylon 12, nylon 11, nylon 46,
Polyester such as polybutylene terephthalate, polyarylate, polyurethane, polyacetal, polycarbonate, polyphenylene oxide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, polysulfone, polyether sulfone, polyallyl sulfone, polyether ketone, polyether ether ketone,
It is also possible to use a mixture of one or more types of homopolymers, random or block copolymers, and graft copolymers such as polyimide, polyamideimide, silicone resin, and phenoxy resin.

In the present invention, the method for blending carbon fibers and lubricating components with polyphenylene sulfide having a desired melt viscosity may be a -membrane melt-kneading method.

For example, a method of tri-blending polyphenylene sulfide resin and carbon fibers and then melt-kneading them in an extruder to produce pellets, or a method of supplying polyphenylene sulfide resin and carbon fibers from different supply ports of an extruder, melt-kneading them, and then producing pellets. method, or a combination of these methods.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples, but they are not intended to limit the scope of the present invention in any way.

The melt viscosity of polyphenylene sulfide resin; η is measured using a Koka type flow tester (Dice: inner diameter 0.5 mm, length 2.
0 mm; load 10 kg).

Non-Newtonian index (n
) and melt viscosity (η) using a capillary rheometer with an inner diameter (D) of 1 mm and a length (L) of 60 mm.
, L/D -60 dice were used, and the measurement temperature was 300°C. Non-Newtonian index is 10 to 1
,000 (sec) of shear stress versus shear rate, which was calculated from the slope of each logarithmic plot. Also,
The value at a shear rate of 200 (sec-1) was defined as the melt viscosity.

The limit press-in allowance was used as a guideline for evaluating toughness. The limit press-fit allowance was calculated based on the formula below by finding the maximum bottle diameter that would not break any of the five samples when a pin with a diameter larger than d was forcibly inserted into the hole of a molded product having a welded part.

Limit press-in allowance - (D-d)/dX100 (%) For evaluation of sliding characteristics, the friction coefficient and specific wear amount are JIS K-7
218A method.

The measurement was carried out using an EFM-m-F thrust type tester manufactured by Orientic Co., Ltd. The test conditions are as follows.

Atmosphere temperature: 23°C Compatible material: 545C cylinder test load 5. 0 kg f /cIly Sliding speed 50 cm/see.

Sliding distance: 30myo Also, as a guideline for strength during sliding, the limit PV value is 7! lI
] has been established. The testing machine and ambient temperature were the same as above.

The specific conditions are as follows.

Sliding speed 50cm/see Test load Initial test load 5.0kgf every 10 minutes 5.
For evaluation of Okgf increase paris, the length of pari when a good molded product was obtained using a bending test piece mold having a clearance of 15μ was measured using a universal projector (V-12 manufactured by Nippon Kogaku Kogyo Co., Ltd.) .

Reference Example 1 Crosslinked PPS within the scope of the present invention was synthesized by the following method.

8000 g of N-methyl-2-picolidone (hereinafter abbreviated as NMP) was placed in an autoclave with an internal volume of 15 L equipped with a stirrer.
and soda sulfide (purity N a , S 60 , 2
wt%) 17.75 mol, stirred under a nitrogen stream, heated to 205°C, and mixed with 390 g of water and 12 g of N M
P was distilled off. After cooling the system to 130°C, 17.54 mol of p-dichlorobenzene and N PvI P 95
0 g was added thereto, the temperature was raised to 225°C over 11 minutes, the mixture was reacted at 225°C for 2 hours, and then the temperature was raised to 250°C over 30 minutes, and the mixture was reacted for 3 hours.

After the reaction was completed, the reaction product was cooled to room temperature and the polymer was isolated using a centrifuge. By repeatedly washing the polymer with hot water and drying it at 100°C overnight, the melt viscosity was reduced to 56.
A polyphenylene sulfide resin of 0 poise was obtained.

When this was cured in air at 250° C. for 2 hours, a crosslinked pps having a melt viscosity of 4500 poise and a non-Newtonian index of 1.35 was obtained.

Reference Example 2 Linear PPS outside the scope of the present invention is disclosed in Japanese Patent Application Laid-Open No. 61-73
It was manufactured by the method disclosed in No. 32.

NM in an autoclave with an internal volume of 15 L equipped with a stirrer.
P8250g and sodium sulfide pentahydrate N a S ・5
Charge 75 mol of H2018, stir under nitrogen stream, raise the temperature to 205°C, and add 1250 g of water and 24 g of NMP.
was removed. At this time, 0.38 mol of NaS was added to H2
It decomposed into S and disappeared. After cooling the system to 130°C,
18.74 moles of p-dichlorobenzene and 960 g of NMP
was added, and polymerization was carried out at 210°C for 10 hours. Add 5 ounces of water to this
1. Add Og (adjust the moisture content in the system to H2S/Na2S - 4,5), enclose the system under a nitrogen stream, and raise the temperature to 250°C.
Polymerization was carried out for 0 hours. The yield of the obtained polymer was 88%,
Melt viscosity is 2850 poise, non-Newtonian index is 1.0
It was 5.

Reference Example 3 An uncured branched PPS resin within the scope of the present invention was produced by the following method.

NM in an autoclave with an internal volume of 15 L equipped with a stirrer.
P 5000 g and sodium sulfide (purity: Na2
Add 14.8 mol of S (60.2 wt%) and heat at 205°C.
380 g of water and 10 g of NMP were distilled off. Subsequently, 14.5 mol of p-dichlorobenzene was added,
After heating at 230°C for 2 hours, a solution of 0.020 mol of 1,2.4-trichlorobenzene in NMP20, Og was added using a pressure pump, and the mixture was further heated at 250°C for 3 hours. After the reaction was completed, the reaction product was cooled to room temperature and the polymer was isolated using a centrifuge. The polymer was repeatedly washed with warm water and dried at 100° C. for a day and night to obtain a polyphenylene sulfide resin having a melt viscosity of 2,600 poise and a non-Newtonian index of 1.32.

Example 1 Crosslinked PP within the scope of the present invention obtained in Reference Example 1,
Carbon fiber (short fiber length 3 mm) for 5100 parts by weight
) was blended and melt-kneaded using an extruder to produce pellets. Molding was performed using this pellet, and the critical press-fitting allowance, sliding characteristics, and par length were measured. The results are shown in Table-1.

Comparative Example 1 Cross-linked ppsr Rydon P-4 manufactured by Philips Vetroleum International, which is outside the scope of the present invention
J (melt viscosity 2200 poise, non-Newtonian exponent 1
．． 73) 28 parts by weight of carbon fiber was blended with 100 parts by weight, and the same operation as in Example 1 was performed. The results are shown in Table-1.

Comparative Example 2 Linear PP5 obtained in Reference Example 2 and outside the scope of the present invention
28 parts by weight of carbon fiber was added to 100 parts by weight, and the same operation as in Example 1 was performed. The results are shown in Table-1.

Example 2 Branched PP5 within the scope of the present invention obtained in Reference Example 3
28 parts by weight of carbon fiber was added to 100 parts by weight, and the same operation as in Example 1 was performed. The results are shown in Table-1.

Comparative Example 3 28 parts by weight of glass fibers were blended with 5100 parts by weight of PP obtained in Reference Example 1, and the same operation as in Example 1 was performed. The results are shown in Table-1.

Comparative Example 4 70 parts by weight of carbon fiber was blended with 5100 parts by weight of PP obtained in Reference Example 1, and the same operation as in Example 1 was performed. The results are shown in Table-1.

Example 3 28 parts by weight of carbon fiber and 5100 parts by weight of PP obtained in Reference Example 1, tetrafluoroethylene resin rKT manufactured by Kitamura Co., Ltd.
14 parts by weight of L-600j was blended and the same operation as in Example 1 was performed. The results are shown in Table-1.

[Effects of the Invention] As is clear from the above description, the present invention achieves the conventional crosslinking by blending a specific amount of carbon fiber and a specific amount of a lubricating component into a polyphenylene sulfide resin having limited fluidity. A resin composition can be obtained that has both mechanical strength and sliding properties that are not sufficient with type polyphenylene sulfide.

Furthermore, this composition has the characteristic of suppressing the occurrence of flaking, which has been a problem with linear polyphenylene sulfide resin compositions, and is suitable for various sliding parts such as bearing retainers, gears, pulleys, etc. It is expected that it will be applied as a material in the automobile, electrical and electronic, and mechanical fields.

Claims (2)

[Claims] (1) Melt viscosity measured at 300°C; relationship between η poise and non-Newtonian index; n is expressed by the following formula (a) 2.5n-1.0≦logη≦2.5n+0.3 (b) 2.9≦ logη (c) 1.1≦n≦1.6 A resin composition comprising 10 to 40 parts by weight of carbon fiber based on 100 parts by weight of a polyphenylene sulfide resin that satisfies all of 1.1≦n≦1.6. (2) Melt viscosity measured at 300°C; The relationship between η poise and non-Newtonian index: n is expressed by the following formula (a) 2.5n-1.0≦logη≦2.5n+0.3 (b) 2.9≦ logη (c) 10 to 60 parts by weight of carbon fiber and 1 to 2 parts by weight of polyphenylene sulfide resin that satisfies all of 1.1≦n≦1.6
A resin composition comprising 0 parts by weight of a lubricating component.