JPH1163238A - Polymeric compound sliding member and double-belted press device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymeric compound sliding member that has sufficient strength to withstand high temperature and pressure, such little frictional resistance to a belt as not to gall it, preferable conformability with a belt and sealing performance and enough insusceptibility to pressure media, and provide a double-belted press using the same sliding member as its sealing member. SOLUTION: A polymeric compound sliding member comprises polyether sulfone in an amount of 45 to 65 wt.%, polytetrafluoroethylene in an amount of 15 to 25 wt.%, and an aromatic polyester homopolymer in an amount of 20 to 30 wt.%, or alternatively comprises a polyimide of pyromellitic acid dianhydride in an amount of 75 to 95 wt.%, polytetrafluoroethylene in an amount of 5 to 15 wt.%, and graphite in an amount of 0 to 10 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is useful as a sealing member for a pressure medium in a double-belt press or the like.
The present invention relates to a polymer composite sliding member (hereinafter simply referred to as a sliding member) having excellent durability in high-temperature and high-pressure molding, and a double-belt press using the same.

[0002]

2. Description of the Related Art An outline of a double belt type press apparatus which is one application of the sliding member of the present invention is taken along a vertical sectional front view shown in FIG. 4 and an arrow AA in FIG. 4 shown in FIG. A description will be given based on a vertical sectional side view. In these figures, 41a, 41
b is a roll, 42 is an endless belt made of stainless steel or the like rotated by the rolls 41a and 41b, 43 is two belts 42
The workpiece 44 which is pinched up and down and moves in the direction of the arrow in FIG.
The pressurizing chambers provided on the outside of each of the pressurizing chambers, 46 are side walls demarcating each pressurizing chamber 44, 47 is a partition wall dividing the pressurizing chambers 44 back and forth, and 48 is built in the pressurizing chambers 44. Pressurized cooling oil,
A pressure medium such as lubricating oil, 49 is a seal member mounted along the edge of each wall 46, 47 of the pressurizing chamber 44 facing the belt 42,
The pressure medium 48 is prevented from leaking from the pressurizing chamber 44.
50 and 51 are a supply port and a discharge port of the pressure medium 48 to the pressurizing chamber 44, respectively.

[0003] The required characteristics of a seal member for this type of application include, first, a strength that can withstand molding conditions (pressure and temperature), and second, a friction coefficient with the belt is small. Thirdly, there is good ability to follow the belt, fourthly, good sealing of the pressure medium, fifthly, not to be affected by the pressure medium. Conventionally, as a sealing member having such characteristics, polytetrafluoroethylene (hereinafter referred to as PTFE) resin, epoxy resin, urethane resin, silicone resin, etc.
Composite by adding graphite, molybdenum disulfide, PTFE powder, impregnating or laminating synthetic resin material or rubber-based material on cloth, mat, non-woven fabric made of various fibers such as carbon fiber, glass fiber, synthetic fiber What was processed was used.

[0004] Conventional main products of the double belt type press machine are metal sheets, cloths, nonwoven fabrics and printing sheets based on thermosetting resins such as melamine resin, diallyl phthalate resin, unsaturated polyester resin and urethane resin. In such a laminated sheet, the molding conditions at that time were generally a pressure of 20 kg / cm ² or less and a temperature of 160 ° C. or less, so the above sealing member was sufficient.

[0005] In recent years, however, the proportion of thermoplastic resin in products manufactured by the double belt press has increased, and the content of the products has been diversified accordingly. When the purpose of thermoplastic resin is to reduce shrinkage and alleviate internal strain,
It was necessary to mold at as high a temperature as possible. For example, in the case of vinyl chloride resin, a temperature of about 180 ° C. and a pressure of 30 kg / cm ² were required.
Polycarbonate, polymethylpentene polymer,
For heat-resistant thermoplastic resins such as polyaryl and polybutylene terephthalate, for the purpose of glazing the surface and alleviating internal strain of the laminate, the temperature should be around 200 ° C and the pressure should be 30kg.
/ cm ² or more. Further, thermosetting resins are increasingly required to be molded at high temperatures and high pressures from the application point of view.

Conventionally, the heat resistance and mechanical strength of a fluororesin material itself represented by PTFE, which is known as an optimum material having a small coefficient of friction with a stainless steel belt and not damaging the stainless steel belt, is 160 ° C. , 30 kg / cm ² is a conditional limit. From a similar point of view, resins such as polyamide imide, aromatic polyester copolymer, polyphenylene sulfide are also unsuitable, and the use of reinforcing materials such as glass fiber, carbon fiber, aramid fiber is unsuitable because they damage stainless steel belts. . As described above, since the conventional sealing member is extremely limited to a material having a sufficient sealing function even at a temperature of 160 ° C. or higher, a material having a relatively high friction coefficient is used, and the back surface of the belt and the sealing member are not sealed. The frictional force generated between them has caused the belt and the seal member to be damaged.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and has a strength enough to withstand high temperature and high pressure, a low frictional resistance with the belt, and no damage to the belt. Good followability and sealability to, suitable as a seal member that is not affected by the pressure medium,
A sliding member and a double-belt press using the same are provided.

[0008]

According to a first aspect of the present invention, there is provided a sliding member comprising 45 to 65% by weight of polyether sulfone, 15 to 25% by weight of PTFE, and 20 to 30% by weight of fragrance. Aromatic polyester homopolymer, 75-95% by weight of pyromellitic dianhydride (hereinafter referred to as PMDA)
Consisting of polyimide and 5 to 25% by weight of PTFE, or 75 to 95% by weight of PMDA type polyimide and 5 to 5% by weight
It is characterized by comprising 15% by weight of PTFE and 0.1 to 10% by weight of graphite.

The double-belt press using the sliding member is provided with two belts which rotate while nipping the object to be processed up and down. A double-belt press apparatus comprising a pressurizing chamber each containing a pressure medium on the outside thereof, wherein at least a part of the side wall constituting the pressurizing chamber is formed along an edge of the side wall facing the belt, at least in part. At least one kind of sliding member according to any one of claims 1 to 3 is mounted as a pressure medium sealing member.

In the double-belt press apparatus, each pressurizing chamber is divided into front and rear by a partition wall, and a front side wall of the front pressurizing chamber, a partition wall, and Along the edges of the rear side wall of the rear pressurizing chamber.
It is preferable that the sliding member described above is used, and the sliding member according to claim 1 is used along each edge of the remaining side wall.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In order to solve the above problems, the inventors of the present invention have proposed lubricating aids such as graphite and molybdenum sulfide for various heat-resistant plastics such as polyimide, wholly aromatic polyester, polyethersulfone and polyamideimide. As a result of examining the possibility of practical use as a seal member for a member obtained by molding with an agent added, the sliding member has self-lubricating properties and flexibility, sliding characteristics, heat-resistant mechanical strength And the sliding member according to claim 1 has a temperature of 190 ° C. and a pressure of 100 kg / cm ² ,
The sliding member according to claim 2 or 3, wherein the temperature is 220 ° C and the pressure is
It was confirmed that there was no problem as a sealing member even under each condition of 100 kg / cm ² , and the present invention was reached.

The polyether sulfone used in the first aspect of the present invention is an amorphous thermoplastic polymer obtained by a polycondensation reaction of dichlorodiphenyl sulfone, and has a chemical structure represented by the following chemical formula (1). N in the formula is a positive integer, and the same applies to the following chemical formulas (2) to (4).

Embedded image The glass transition temperature is 225 ° C, the specific gravity is 1.37, and it has excellent heat resistance. The thermal deformation temperature is 203 ° C (18.6 kg / cm ² ), and it has excellent mechanical strength. As a commercially available product of this compound, for example, product number 4100G manufactured by Sumitomo Chemical Co., Ltd. is known.

A similar aromatic polyester homopolymer is a crystalline polymer obtained by a polycondensation reaction of p-hydroxybenzoic acid and has a chemical structure represented by the following chemical formula 2.

Embedded image This specific gravity is 1.44 and hardly flows at temperatures below 400 ° C,
Excellent wear resistance and self-lubricating properties. Tensile strength at room temperature
It is not so strong, 150-200 kg / cm ^2, and the hardness is relatively soft such as Shore D87. As a commercially available product of this compound, for example, product number E101 manufactured by Sumitomo Chemical Co., Ltd. is known.

The PMDA-type polyimide used in the invention of claim 2 is a polymer obtained by a polycondensation reaction between an aromatic diamine and tetracarboxylic dianhydride, and has a chemical structure represented by the following chemical formula 3.

Embedded image This specific gravity is 1.43, which is extremely excellent in heat resistance and does not decompose up to 500 ° C. The tensile strength is 700-900 kg / cm ² at room temperature. Commercially available products of this compound include, for example, DuPont product number SP
-1 is known.

PTFE is obtained by polymerization of tetrafluoroethylene and has a chemical structure shown in the following chemical formula 4.

Embedded image Its specific gravity is 2.13 to 2.22, its melting point is 327 ° C, and its tensile strength is 140 to 350 kg / cm ² at room temperature.

PT based on polyethersulfone
FE, a complex of wholly aromatic polyester homopolymer,
After kneading and extruding under appropriate conditions to form pellets, the resulting product can be formed into a block by an extruder and cut or injection-molded to obtain a sliding member of a final product. PTF based on PMDA type polyimide
The composite of E or PTFE and graphite can be formed into a block by a compression molding machine and then cut to obtain a final product.

The sliding member of the present invention has excellent sliding characteristics such that the frictional resistance with the stainless steel belt is extremely small and the stainless steel belt is not damaged. This is considered to be due to the flexibility as much as possible while maintaining the minimum heat resistance. On the other hand, in the sliding member according to claim 1,
It is considered that PTFE and the wholly aromatic polyester homopolymer act to reduce the coefficient of friction and impart flexibility, and polyethersulfone acts as a binder and maintains heat resistance. On the other hand, in the sliding member according to the second or third aspect, PTFE and graphite act to impart a reduction in the coefficient of friction, and PTFE, graphite mainly imparts flexibility.
Therefore, it is considered that PMDA-type polyimide acts, and furthermore, PMDA-type polyimide mainly acts as a binder and maintains heat resistance.

Next, a double-belt press using the sliding member of the present invention will be described with reference to FIGS. FIG. 1 shows the sliding member of the present invention as a seal member along the edge of each wall constituting the pressurizing chamber of the same double-belt press apparatus as shown in FIGS. FIG. 2 is an explanatory rear perspective view of the seal member shown in FIG. In each of these figures, reference numeral 1 denotes a side wall of the pressurizing chamber 2, which is provided with a U-shaped groove 4 at an end surface thereof along an edge facing the belt 3, and in which a sealing member 5 is provided with a back pressure oil. It is slidably mounted in the vertical direction via the oil reservoir 6 of A. Inside the seal member 5, supply passages 7, 8, 9 and a supply groove 10 for the float oil B to the contact surface with the belt 3 are provided.
The pressure medium C that tends to leak from inside into the gap 11 between the seal member 5 and the belt 3 is prevented by the pressing of the seal member 5 and the supply pressure of the float oil B.

As shown in FIG. 3, the side walls constituting the pressurizing chamber 2 include a side wall 12 defining the periphery and a partition wall 13 dividing the pressurizing chamber 2 into front and rear pressurizing chambers 21 and 22. At least one sliding member according to any one of claims 1 to 3 is mounted as a seal member on at least a part of the side wall 12, 13 along an edge of the side wall facing the belt. However, the edges of the front side wall of the front pressure chamber 21, the partition wall 13, and the rear wall of the rear wall of the rear pressure chamber 22 [particularly, the region filled in FIG. Since the sliding member according to claim 2 or 3 having excellent strength is used, each edge of the remaining side wall (particularly, a hatched area in FIG. 3 (c)) can be operated at a relatively low temperature. It is preferable to use the sliding member described in 1.

[0020]

The present invention will be described below more specifically with reference to examples and comparative examples. The methods for measuring physical properties used in each example are as follows. -Coefficient of friction: Measured with a Matsubara friction and wear tester at a pressure of 100 kg / cm ² , a peripheral speed of 6 m / min, and a lubricating oil using Lucant HC40 (Mitsui Petrochemical Co., Ltd.). Hardness: Rockwell or Shore hardness.・ High temperature compressive strength: Measure the compressive deformation rate by applying a load of 100 kg / cm ² for 10 minutes while maintaining the specified temperature. -Tensile strength, bending strength, compressive strength: measured by ASTM method.

Example 1 A resin composition comprising 55% by weight of polyether sulfone, 20% by weight of PTFE, and 25% by weight of an aromatic polyester homopolymer was molded and processed to have the basic physical properties shown in Table 1. A sliding member was obtained. This is cut into a double-belt type press device (the material of the belt used is SUS304, and the thickness is 0.8 mm to 1.5 mm), and it is cut into a groove on the side wall end face of the pressure chamber shown in FIG. When passed through a polycarbonate sheet at 190 ° C, pressure of 100 kg / cm ² and speed of 20 m / min, there was no damage on the belt, no deformation or breakage of the seal member, and no abnormality in the driving load, and there was no problem in production. It was confirmed that.

Example 2 A resin composition comprising 85% by weight of PMDA-type polyimide, 10% by weight of PTFE and 15% by weight of graphite was molded and processed. As a result, a sliding member having the basic physical properties shown in Table 1 was obtained. Obtained. This was cut in the same manner as in Example 1 and similarly mounted as a seal member on the side wall of the pressurizing chamber, and passed through a polycarbonate sheet at a temperature of 220 ° C., a pressure of 100 kg / cm ² and a speed of 20 m / min. Example 1
It was confirmed that there was no problem in production as well as.

Examples 3 to 4 and Comparative Examples 1 to 12 Table 1
When the resin composition having the composition shown in FIG. 4 was molded in the same manner as in Example 1, molded articles having the basic physical properties as described in each table were obtained. This was cut in the same manner as in Example 1 and mounted on a real machine as a seal member.
C., the maximum pressure was 100 kg / cm ² , and the maximum speed was 20 m / min. When the sheet was passed through the polycarbonate sheet, the results as shown in each table were obtained.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

[Table 4]

In the actual machine, lubricating oil is forcibly supplied between the belt and the seal member. However, in practice, an ideal oil film is not always formed, and a non-lubricated state is assumed. It is necessary to select a suitable material. For example, as can be seen in Comparative Examples 2, 3 and 4, those having a relatively low friction coefficient when using a lubricating oil but having a large friction coefficient in an unlubricated state have a large frictional resistance with the belt. It is presumed that this is the main cause of injuries.

The results of Example 1 are very good because the coefficient of friction is stable at a very small value both in the case of using lubricating oil and in the non-lubricated state, and the hardness is not so high. Probable cause. Further, in Example 2, although the coefficient of friction in the non-lubricated state tends to be slightly higher, the reason why the result is very good is considered to be that this is assisted by the softness of the member.

As shown in each of these examples, as a result of conducting experiments on various combinations of compositions, a seal member which can be used if the composition ratio is within the range of the composition ratio of the present invention is exceeded. In this case, it was confirmed that the belt was liable to be damaged and a problem occurred in terms of heat resistance.

Actual Machine Test Each sample obtained in Examples 1, 3 and Comparative Example 1 was prepared for a sealing member, and the respective external dimensions (length × width × length):
25 × 25 × 1025 (mm), Float oil supply passage 8: Inner diameter 6.0mm
(A SUS pipe with an inner diameter of 8 mm is attached only to the seal member of Comparative Example 1), 9: 2.0 mm inner diameter (1.0 mm inner diameter only of the seal member of Comparative Example 1), a float oil supply groove 10: depth 1.0 mm, width 14 m
m and a length of 169 mm, a sealing member having the shape shown in FIGS. 1 and 2 was prepared, and mounted on the wall of the pressure chamber in the arrangement shown in FIGS. 3 (a) to 3 (c). In each of the figures, the outline is Comparative Example 1,
The hatched portions represent the seal members obtained in Example 1 and the black portions represent the seal members obtained in Example 3.

In the arrangement of the seal member shown in FIG.
Immediately, cooling oil is applied to the back surface of the belt immediately before entering the pressurizing chamber to protect the seal member according to Comparative Example 1 from heat,
The test was conducted at a belt speed of 5 m / min and an inlet temperature of 175 to 180 ° C. Until the 1000 m length running, the driving load was stable at a low level of around 32 A, and abnormalities in the load and damage to the sealing member and belt were observed. Did not. With the arrangement of the seal member shown in FIG. 3 (b), a test was conducted at the same belt speed and inlet temperature as above, and no damage to the seal member or the belt was observed up to a running length of about 50,000 m. However, when the vehicle was allowed to run for a longer period of time, cracks were observed in the seal members according to Example 1 on both side walls of the pressure chamber entrance. Regarding the cause, the corner portion is a portion having the smallest push-up area due to the float hydraulic pressure, and a larger pressure is applied structurally than other places.
It was judged that the sealing member of FIG.
The test was performed again with the arrangement of the seal members shown in (c). As a result, no abnormalities were found in the long-term running test.

[0033]

The sliding member based on the polyether sulfone of the present invention has a temperature of 190 ° C., a pressure of 100 kg / cm ² , and a speed of 2 kg.
Under the condition of 0 m / min, and the sliding member based on PMDA type polyimide, temperature 220 ° C, pressure 100kg / cm ² , speed 20
Under the conditions of m / min, it became possible to use each as a seal member of a double belt press machine. This facilitates the processing of heat-resistant thermoplastic resins such as polycarbonate, polymethylpentene polymer, polyaryl, and polybutyl terephthalate, such as surface gloss lamination and internal strain relaxation, and the sliding member of the present invention has improved durability. Because it is superior, it is advantageous in terms of cost and has a great industrial effect.

[Brief description of the drawings]

FIG. 1 is an enlarged vertical sectional view showing a state where a sliding member of the present invention is mounted as a seal member on a side wall of a pressurizing chamber of a double belt press device.

FIG. 2 is an explanatory rear perspective view of a seal member used in FIG. 1;

3 (a) to 3 (c) are plan views when various sealing members are arranged and mounted on side walls constituting the pressurizing chamber shown in FIG. 1, respectively.

FIG. 4 is a schematic longitudinal sectional view showing an example of a double-belt press apparatus which is one application of the sliding member of the present invention.

FIG. 5 is a schematic longitudinal sectional view of the device shown in FIG. 4, taken along the line AA.

[Explanation of symbols]

1 ... side wall, 2 ... pressurized chamber, 3 ...
Belt, 4 ... groove, 5 ... seal member,
6 ... oil pool, 7, 8, 9 ... supply passage, 10
... Supply groove, 11 ... Gap, 12 ... Side wall,
13 ... partition wall, 21 ... front pressurized chamber, 22 ... rear pressurized chamber, A ... back pressure oil, B ... float oil,
C: pressure medium, 41a, 41b: roll,
42 ... belt, 43 ... workpiece, 44 ... pressurizing chamber,
45: clamping section, 46: side wall, 47: partition wall, 48: pressure medium, 49: sealing member, 50: supply port, 51: discharge port.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 79/08 C08L 79/08 81/06 81/06 C09K 3/10 C09K 3/10 M C10M 107/38 C10M 107/38 / / C10N 40:02 40:34 50:08

Claims (5)

[Claims] (1) 45-65% by weight of polyether sulfone and 15
A polymer composite sliding member comprising -25% by weight of polytetrafluoroethylene and 20-30% by weight of an aromatic polyester homopolymer. 2. A polymer composite sliding member comprising 75 to 95% by weight of pyromellitic dianhydride type polyimide and 5 to 25% by weight of polytetrafluoroethylene. 3. A polymer composite slide comprising 75 to 95% by weight of pyromellitic dianhydride type polyimide, 5 to 15% by weight of polytetrafluoroethylene and 0.1 to 10% by weight of graphite. Moving member. 4. A double-belt press apparatus comprising two belts which rotate while nipping an object to be processed up and down, and a pressurizing chamber containing a pressure medium inside each of the two belts at an nipping portion. The at least one kind of polymer composite slide according to any one of claims 1 to 3, wherein at least a part of the side wall constituting the pressurizing chamber is arranged along an edge of the side wall facing the belt. A double-belt press device in which a member is mounted as a pressure medium seal member. 5. Each of the pressurizing chambers is divided into front and rear by a partition wall, and along each edge of the front side wall of the front pressurizing chamber, the partition wall, and the rear side wall of the rear pressurizing chamber. The double belt type according to claim 4, wherein the polymer composite sliding member according to claim 2 or 3 is used, and the polymer composite sliding member according to claim 1 is used along each edge of the remaining side wall. Press equipment.