JPH05170937A - Sliding sheet made of thermoplastic polyimide resin and its production - Google Patents

Abstract

PURPOSE:To obtain the subject sheet having a prescribed thickness and excellent heat-resistance, sliding property, load resistance, seizing resistance and workability and useful for sliding member such as bearing by melt-forming a specific resin composition in the form of a sheet and casting the sheet with a roll under specific condition. CONSTITUTION:The objective sheet having a thickness of 50-500thetam can be produced by compounding (A) 100 pts.wt. of a thermoplastic polyimide resin with (B) 1-50 pts.wt. of a sliding material consisting of a sliding material selected from metal fluoride powder, potassium titanate fiber, carbon powder, carbon fiber, boron nitride powder, glass powder, alumina powder, aluminum nitride powder, fluororesin powder and hardened phenolic resin powder or a mixture of two or more kinds of the above substances, melting and forming the obtained resin composition at a temperature between Tm and Tm+50 deg.C (Tm is the melting point of the polyimide resin) in the form of a sheet and casting the sheet with a roll having a surface temperature lower than the glass transition temperature of the polyimide resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding sheet having a thermoplastic polyimide matrix and a method for producing the sliding sheet. More specifically, a sliding sheet using a thermoplastic polyimide matrix that can be impregnated and coated on the surface of a porous metal layer lined with a metal backing by heat compression, etc. and has excellent heat resistance and abrasion resistance. And a manufacturing method thereof.

[0002]

Layered plain bearings are widely used as mechanical elements for transmission of moving mechanical parts to stationary mechanical parts. This plain bearing consists of two materials with different mechanical properties, one of which is a support or substrate that carries the bearing material and mainly guarantees load bearing, and the other is in all driving conditions. It is a bearing material layer that guarantees a synergistic movement between the movable bearing member and the stationary bearing member without disturbance. Bearing stress given by the load carried,
Depending on the sliding speed and the structural peculiarities, various metallic sliding materials and non-metallic sliding materials have been conventionally used in sliding bearings.

The most well-known metallic materials are, for example, lead-copper compounds, tin, cadmium, etc. As non-metallic materials, graphite and special resins such as phenol resin or polyfluoroolefin are known. There is.

However, not only wear resistance but also heat resistance have been required for these sliding materials. A polyimide film is an example of a plastic material having excellent heat resistance. Since a conventional polyimide film is difficult to thermoform, it is manufactured by a so-called solution casting method in which a solution of a polyamic acid that is a precursor of polyimide is cast to manufacture. Therefore, it is difficult to manufacture a sliding sheet having a thickness of more than 150 μm, and even if the film has a thickness of 150 μm or less, an adhesive must be used for bonding to a metal, and the heat resistance of the adhesive is high. If it is inferior, it has a defect that it cannot be used under high temperature conditions.

[0005]

An object of the present invention is to have excellent heat resistance and wear resistance, and to easily impregnate / cover the surface of a porous metal layer lined with a metal backing of the main part of a sliding component. Another object of the present invention is to provide a sliding sheet and a manufacturing method thereof.

[0006]

As a result of extensive studies to solve the above problems, a sheet obtained by mixing a thermoplastic polyimide resin and a sliding material with a specific composition and melt-forming the above problems solves the above problems. Found to have possible properties,
The present invention has been reached.

That is, in the first invention of the present invention, the thickness obtained by melt molding a resin composition containing 100 parts by weight of a thermoplastic polyimide resin and 1 to 50 parts by weight of a sliding material is 50 to 500 μm. It is a sliding sheet.

The second aspect of the present invention is to add a resin composition obtained by adding and mixing 1 to 50 parts by weight of a sliding material to 100 parts by weight of a thermoplastic polyimide resin and mixing the resin composition with a melting point of the polyimide resin. Of a sliding sheet having a thickness of 50 to 500 μm, which is characterized by being melt-formed into a sheet at a temperature of melting point + 50 ° C. and then cast using a roll having a surface temperature lower than the glass transition temperature of the polyimide resin. It is a manufacturing method.

The feature of the sliding sheet of the present invention is that it has excellent heat resistance, slidability, load resistance, and seizure resistance, and that the surface of the porous metal layer backed by the metal backing of the sliding part is heat-treated. The point is that it has thermoplasticity that can be easily impregnated and coated with a press or the like.

The present invention will be described in detail below. The thermoplastic polyimide resin used as the matrix of the sliding sheet of the present invention is represented by the general formula (1) [Chemical formula 1] already known as a heat-resistant polyimide resin.

[0011]

[Chemical 1] (In the formula, R and R ₁ are an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, a monocyclic aromatic group, a condensed polycyclic aromatic group, and an aromatic group, which are directly or crosslinked with each other. A group selected from the group consisting of non-fused polycyclic aromatic groups linked to
Is a tetravalent group and R ₁ is a divalent group), and a polyimide resin having thermoplasticity is used among those having a repeating structural unit represented by Preferably, the general formula (2)
[Chemical 2]

[0012]

[Chemical 2] (In the formula, R is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group,
A tetravalent group selected from the group consisting of a monocyclic aromatic group, a condensed polycyclic aromatic group, and a non-condensed polycyclic aromatic group in which aromatic groups are connected to each other directly or by a crosslinking member. , X is a single bond, a sulfur atom, a sulfone group, a carbonyl group, an isopropylidene group or a hexafluoroisopropylidene group.
And a polyimide resin having a repeating structural unit represented by the general formula (3)

[0013]

[Chemical 3] [In the formula, A represents a divalent group such as a sulfur atom, an oxygen atom, a sulfone group, a methylene group, an ethylidene group, an isopropylidene group or a hexafluoroisopropylidene group, and R is a general formula (4)

[0014]

[Chemical 4] (In the formula, B represents a divalent group such as a sulfur atom, a sulfone group, a methylene group, an ethylidene group, an isopropylidene group or a hexafluoroisopropylidene group), and is a polyimide resin having a repeating structural unit.

Further, the polyimide resin which is preferably used is represented by the following formula (2):
[Chemical Formula 5] to Formula (9) [Chemical Formula 9]

[0016]

[Chemical 5]

[0017]

[Chemical 6]

[0018]

[Chemical 7]

[0019]

[Chemical 8]

[0020]

[Chemical 9] A polyimide resin is a tetravalent group selected from the group consisting of The above polyimide resin can be obtained by a dehydration condensation reaction of an aromatic tetracarboxylic dianhydride and an aromatic diamine.

Examples of the aromatic tetracarboxylic dianhydride used to obtain this polyimide include butanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, pyromellitic dianhydride, and 1,2. , 3,
4-benzenetetracarboxylic dianhydride, 2, 3, 6,
7-naphthalenetetracarboxylic dianhydride, 1,4
5,8-naphthalenetetracarboxylic dianhydride, 1,
2,5,6-naphthalenetetracarboxylic dianhydride,
3,4,9,10-perylene tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride, 1,2,7,8-phenanthrene tetracarboxylic dianhydride, 3, 3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride Things, 2, 2 ', 3,
3'-benzophenone tetracarboxylic dianhydride, 2,
2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride , Bis (2,3-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis (2,3-dicarboxyphenyl) sulfone dianhydride, 2,2- Bis (3,4-dicarboxyphenyl) 1,1,1,3
3,3-hexafluoropropane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) 1,1,1,3
3,3-hexachloropropane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride,
Bis (3,4-dicarboxyphenyl) methane dianhydride, 4,4 ′-(p-phenylenedioxy) diphthalic acid dianhydride, 4,4 ′-(m-phenylenedioxy) diphthalic acid dianhydride 4,4'-diphenyl sulfide dioxybis (4-phthalic acid) dianhydride, 4,4'-diphenyl sulfone dioxybis (4-phthalic acid) dianhydride,
Methylenebis- (4-phenyleneoxy-4-phthalic acid) dianhydride, ethylidene bis- (4-phenyleneoxy-4-phthalic acid) dianhydride, isopropylidene bis- (4-phenyleneoxy-4-phthalic acid) dianhydride Examples thereof include acid anhydrides and hexafluoroisopropylidene bis- (4-phenyleneoxy-4-phthalic acid) dianhydride.

Examples of the aromatic diamine used to obtain the polyimide include bis [4- (3-aminophenoxy) phenyl] sulfide and bis [4- (3-
Aminophenoxy) phenyl] sulfone, bis [4-
(3-Aminophenoxy) phenyl] ketone, 4,4 ′
-Bis (3-aminophenoxy) biphenyl, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1 , 3,3,3-hexafluoropropane, 4,4'-diaminodiphenyl sulfide, 4,
4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenylmethane, 1,1-di (p-aminophenyl) ethane,
2,2-di (p-aminophenyl) propane, 2,2-
Di (p-aminophenyl) -1,1,1,3,3,3-
Hexafluoropropane and the like can be mentioned. These aromatic tetracarboxylic dianhydrides or aromatic diamines can be used alone or in admixture of two or more.

The polyimide resin used in the present invention can be prepared by subjecting these aromatic tetracarboxylic dianhydrides and aromatic diamines to an ordinary known method, for example, suspending or dissolving the monomers or the monomers in an organic solvent. After the reaction, the product can be obtained by a general method of heating or chemically dehydrating, separating and purifying the product.

The above-mentioned thermoplastic polyimide resin used in the present invention may contain, if necessary, a lubricant, a heat stabilizer, cadmium sulfide, phthalocyanine, carbon black, titanium oxide, iron oxide unless the effects of the invention are impaired. Pigments and dyes such as lead oxide and cobalt oxide, additives such as UV absorbers, calcium carbonate, talc, clay, silica, graphite, graphite fluoride, aluminum oxide, chromium oxide, zinc oxide, tin oxide, antimony oxide, Surface-modified inorganic filler such as cadmium oxide, carbon fiber, glass fiber, ceramic fiber, fiber reinforcing material such as aromatic amide fiber, stearic acid and its salt, ester, half ester, stearyl alcohol, stearamide, etc. A mold agent may be used in combination.

The sliding material used in the sliding sheet of the present invention includes metal fluoride powder, potassium titanate fiber, carbon powder, carbon fiber, boron nitride powder, glass powder, alumina powder, alumina nitride powder, fluororesin. Examples of the powder include a powder of a phenol resin cured product and the like. These sliding materials may be used alone or as a mixture of two or more kinds. The amount of sliding material used is 100% thermoplastic polyimide resin.
A range of 1 to 50 parts by weight is preferable with respect to parts by weight.

Examples of the fluororesin include polytetrafluoroethylene and the like. When the fluororesin powder is used as the sliding material, it is preferable to add 3 to 35 parts by weight to 100 parts by weight of the thermoplastic polyimide resin. It is more preferably 5 to 25 parts by weight. If the amount of the fluorine resin powder added is less than 3 parts by weight, the effect of improving the low frictional property, non-seizure property and improvement of the limit PV value becomes small, which is not preferable.
On the other hand, if the amount of the fluororesin powder added exceeds 35 parts by weight, the strength of the obtained sheet will be weakened, the load resistance characteristics and creep resistance characteristics will be deteriorated, and the molding processability will be unfavorable.

Examples of the metal fluoride include zinc fluoride, aluminum fluoride, iron fluoride, potassium fluoride, lead fluoride, calcium fluoride, copper fluoride, cadmium fluoride, barium fluoride, lithium fluoride and fluorine. Magnesium fluoride and the like can be mentioned, but lead fluoride or calcium fluoride is particularly preferred. When the metal fluoride powder is used as the sliding material, it is preferable to add 1 to 35 parts by weight to 100 parts by weight of the thermoplastic polyimide resin. It is more preferably 2 to 20 parts by weight.
If the amount of the metal fluoride powder added is less than 1 part by weight, the effect of improving the load resistance property, wear resistance property, seizure resistance property, wear property, and creep resistance property becomes small, which is not preferable. On the other hand, if the amount of the metal fluoride powder added exceeds 35 parts by weight, the strength of the obtained sheet will be weak, the effect of improving the friction characteristics will be weak, and the moldability will be poor, such being undesirable.

When potassium titanate fiber is used as the sliding material, 1 part is added to 100 parts by weight of the thermoplastic polyimide resin.
It is preferable to add ˜20 parts by weight. It is more preferably 2 to 15 parts by weight. When the amount of potassium titanate fiber added is less than 1 part by weight, the load resistance property, wear resistance property,
It is not preferable because the effect of improving the seizure resistance and creep resistance is small. On the other hand, if the amount of potassium titanate fiber added exceeds 20 parts by weight, the frictional characteristics are deteriorated and the molding processability is deteriorated, which is not preferable.

As the phenol resin cured product powder, a resin powder obtained by pulverizing a cured product obtained by curing a phenol resin such as a novolac type phenol resin or a phenol aralkyl resin with a curing agent such as hexamethylenetetramine is exemplified.

When carbon powder, carbon fiber, phenol resin cured product powder, boron nitride, glass powder, alumina, or alumina nitride is used as the sliding material, 1 to 50 parts by weight is added to 100 parts by weight of the thermoplastic polyimide resin. It is preferable to add. It is more preferably 2 to 35 parts by weight. If the amount of these sliding materials added is less than 1 part by weight, the number and height of the protrusions formed on the film surface are small, and the effect of improving the adhesiveness is small, which is not preferable. On the other hand, if it exceeds 50 parts by weight, the strength of the obtained film becomes weak, and the load resistance and creep resistance are deteriorated.
Molding processability deteriorates, which is not preferable. Further, those sliding materials mainly having an average major axis of 1 to 50 μm are preferably used. When a sliding material having an average major axis of more than 50 μm is used for a sheet having a thickness of 500 μm or less, it is effective for forming protrusions on the surface of the sheet, but it substantially gives physical damage to the sheet. Equally, it reduces the mechanical strength of the sheet. Further, when the average major axis is less than 1 μm, it has little influence on the mechanical properties of the sheet,
It is not possible to form protrusions of a size effective for improving adhesiveness on the surface.

As described above, as the sliding material contained in the sliding sheet of the present invention, the above sliding materials can be used alone or in combination of two or more kinds. However, when two or more of them are mixed and used, the total amount is preferably contained in the range of 1 to 50 parts by weight with respect to 100 parts by weight of the thermoplastic polyimide resin. If the amount is less than 2 parts by weight, the effect of each sliding material cannot be sufficiently exhibited, and if it exceeds 50 parts by weight, the molding processability is significantly impaired, which is not preferable.

A method for producing a sliding sheet using the thermoplastic polyimide resin of the present invention as a matrix will be described.

1 to 50 parts by weight of a sliding material is added to 100 parts by weight of a powder of a thermoplastic polyimide having a repeating structural unit represented by the general formula (1), and mixed with a Henschel, a universal mixer, a ribbon blender or the like. Using a device, the mixture is mixed at a temperature near room temperature for about 5 to 30 minutes to obtain a resin composition. The thermoplastic polyimide resin may be melt-molded in advance and used as pellets. Further, the sliding material is prepared by mixing the thermoplastic polyimide resin in a predetermined amount or more in advance and mixing the thermoplastic polyimide powder or pellets into a powder master batch or pellet master batch. You may make it contain a fixed amount of sliding material. There are no particular restrictions on the type of mixing device such as a Henschel, universal mixer, ribbon blender, etc., which may be any one usually used for mixing thermoplastic resins.

The obtained resin composition is subjected to a T-die type extrusion molding method, an inflation type extrusion molding method, a calender type molding method and the like to obtain a melting point of the thermoplastic polyimide resin to a melting point +
It is melt-molded into a sheet at a temperature of about 50 ° C., and then the sheet-shaped molten product is cast on a roll having a surface temperature lower than the glass transition temperature of the thermoplastic polyimide resin to give a thickness of 50 to 500 μm. A sliding sheet having a thermoplastic polyimide matrix is obtained. The thickness of the sheet is controlled by appropriately selecting the conditions such as the lip interval of the T-die and the take-up speed, the interval of the calender roll and the take-up speed or the air blowing speed and the take-up speed, and these and the casting temperature. There are no particular restrictions on the type of T-die type extruder, inflation type extruder, calender molding machine, etc. used, and there is no problem as long as it is one normally used for melt molding of thermoplastic resins.

[0035]

The present invention will be described in more detail with reference to the following examples. Examples 1 to 4 and Comparative Example 1 Thermoplastic polyimide powder A (manufactured by Mitsui Toatsu Chemicals, Inc., trade name: New-TPI, Tg = 250 ° C.) 100
The sliding materials of the types and amounts shown in [Table 1] were added to parts by weight, and mixed for 5 minutes at room temperature using a universal mixer to obtain a resin composition. The resin composition was extruded into a strand at 400 ° C. using a T-die type twin-screw extruder and pelletized with a pelletizer to obtain a polyimide pellet containing a sliding material. The polyimide pellets were melted at 420 ° C. using a T-die type single-screw extruder, the molten resin was extruded from the slit-shaped resin outlet of the T-die, cast on a roll adjusted to 200 ° C., and the thickness was 400 μm. Got the sheet.

As a sample for measuring the dynamic friction coefficient and the limiting PV value, bronze powder was sprinkled to a thickness of 0.4 mm on one surface of a metal plate having a diameter of 50 mm and a thickness of 1.00 mm, and the metal was sintered at 800 ° C. A porous layer was formed. Then, each of the thermoplastic sliding sheets was brought into close contact with the surface of the porous layer, and heat-pressed at 430 ° C. and 100 kg / cm ² to impregnate the sliding sheet into the porous layer and fuse it to
A test piece of a multilayer sliding material having a diameter of 50 mm and a thickness of 1.35 mm was obtained. Furthermore, as a sample for measuring the wear coefficient, a diameter of 5 m
The same treatment as described above was applied to the circular portion of the cylindrical metal having a length of m and a length of 20 mm to obtain a cylindrical test piece having a diameter of 5 mm and a length of 20.35 mm.

Regarding the obtained test pieces, the dynamic friction coefficient and the limit PV value are manufactured by Toyo Seiki Seisakusho Co., Ltd., the thrust wear tester is used, and the wear coefficient is manufactured by Tohoku Seimitsu Industry Co., Ltd., six-piece wear. It measured using the test machine. The measurement conditions are indicated by annotations outside the table [Table 2]. The obtained results are shown in [Table 2].

Examples 5 to 8 and Comparative Example 2 Molding of pellets using polyimide powder B (Mitsui Toatsu Chemicals, Inc., trade name: New-TPI, amorphous grade, Tg = 250 ° C.) as thermoplastic Temperature 3
A sliding sheet having a thickness of 400 μm was obtained in the same manner as in Example 1 except that the temperature was 70 ° C. and the film extrusion temperature was 400 ° C. Then, the obtained sliding sheet was hot-pressed on the same metal porous layer as in Example 1 at 410 ° C. and 100 kg / cm ² to impregnate the porous sliding layer with the thermoplastic sliding sheet and fuse the same to A test piece of the same multi-layer sliding material was obtained. The obtained test piece was evaluated in the same manner as in Example 1. The obtained results are shown in [Table 2].

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

INDUSTRIAL APPLICABILITY The sliding sheet of the present invention has the highest heat resistance, slidability, load resistance, and seizure resistance among sliding sheets using a synthetic resin as a matrix. It is a sliding sheet with good moldability that can be easily impregnated and fused by hot pressing etc. on the surface of the porous metal layer lined with the metal backing of the main part, and can be widely used as a sliding member. it can.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C10M 107: 44 125: 02 125: 10 125: 26 125: 28 125: 20 147: 02 145: 20 ) C08L 79:08 C10N 30:06 30:08 40:02 50:08 70:00 (72) Inventor Yasuko Mitsui Toatsu Chemical Co., Ltd. 2-1, Tangodori, Minami-ku, Aichi Prefecture Nagoya (72) Inventor Yoshiyuki Katsuyama 2-1, Tango Dori, Minami-ku, Nagoya-shi, Aichi Prefecture Mitsui Toatsu Chemical Co., Ltd.

Claims (4)

[Claims] 1. A sliding sheet having a thickness of 50 to 500 μm obtained by melt molding a resin composition containing 100 parts by weight of a thermoplastic polyimide resin and 1 to 50 parts by weight of a sliding material. 2. The sliding material is metal fluoride powder, potassium titanate fiber, carbon powder, carbon fiber, boron nitride powder, glass powder,
The sliding sheet according to claim 1, which is one kind or a mixture of two or more kinds of sliding materials selected from the group consisting of alumina powder, alumina nitride powder, fluororesin powder, and phenolic resin cured product powder. 3. A resin composition obtained by adding 1 to 50 parts by weight of a sliding material to 100 parts by weight of a thermoplastic polyimide resin and mixing them, is a sheet at a temperature of the melting point of the polyimide resin to a melting point + 50 ° C. 1. A method for producing a sliding sheet having a thickness of 50 to 500 μm, which comprises melt-molding into, and then casting using a roll having a surface temperature lower than the glass transition temperature of the polyimide resin. 4. The sliding material is metal fluoride powder, potassium titanate fiber, carbon powder, carbon fiber, boron nitride powder, glass powder,
The method for producing a sliding sheet according to claim 3, wherein the sliding sheet is one kind or a mixture of two or more kinds of sliding materials selected from the group consisting of alumina powder, alumina nitride powder, fluororesin powder, and hardened phenol resin powder.