JP6602135B2 - Molded body and manufacturing method thereof - Google Patents

Description

  The present invention relates to a molded body and a manufacturing method thereof, and more particularly to a molded body suitable for a sealing material and a manufacturing method thereof.

  The sealing material is used as a joint of various plant pipes such as petrochemical, petroleum refining, electric power, paper making, etc., and closes the gap, and at the same time prevents leakage of fluid or entry of foreign matter from the outside.

  As a sealing material, a fluorine-based resin having a high sealing property and a high chemical resistance is used because it is soft and fits well with a close contact member (Patent Documents 1 and 2).

  However, when such a fluororesin seal material is used in a monomer production plant for butadiene, styrene, acrylonitrile, etc., the produced monomer penetrates the seal material and polymerizes within the seal material, thereby There is a problem that the material swells and blocks the pipe, or the sealing material itself is destroyed. In addition, there is a problem that the monomer leaks or the swollen sealing material is peeled off and mixed into the product. For this reason, in Patent Documents 1 and 2, a swelling suppression material is added to the fluororesin.

  Further, a sealing material made of a fluorine-based resin has poor creep resistance, and is unsuitable for use as a sealing material under conditions where a high clamping pressure is required or where repeated stress is applied. Increasing the amount of fillers such as carbon fiber, glass fiber, and carbon black added to the fluororesin to improve creep resistance increases the surface area of the sheet and increases the surface area, making it easier for the monomer to penetrate. As a result, there was a problem that the swelling resistance was lowered.

  On the other hand, a plain bearing using polyether ether ketone (PEEK) having a high fatigue strength and a low friction coefficient is known (Patent Document 3).

Japanese Patent Laid-Open No. 11-7157 JP 2000-179712 A JP 59-182843 A

  The objective of this invention is providing the molded object which can form a sealing material with a long use period and high creep resistance, and its manufacturing method.

The present inventor has intensively studied a sealing material using polyetheretherketone (PEEK) as a sealing material for a ball valve that requires high creep resistance. The PEEK sealing material is solidified by adhesion of monomers or the like to the surface, and the movement of the ball becomes poor or leakage occurs, so that the use period is short and it is necessary to replace it frequently. The present inventor has found that when a polymerization inhibitor is added to polyether ether ketone to produce a sealing material, the adhesion of the monomer to the sealing material is reduced and the period of use can be greatly extended, thereby completing the present invention. .
According to the present invention, the following molded article and a method for producing the same are provided.
1. A molded article containing polyetheretherketone and a polymerization inhibitor.
2. 2. The molded article according to 1, wherein the polymerization inhibitor is one or more selected from an amine compound and a phenol compound.
3. 3. The molded article according to 1 or 2, wherein the content of the polymerization inhibitor is 0.01 to 10% by weight.
4). Furthermore, the molded object in any one of 1-3 containing a fluorine resin.
5). The fluororesin is one or more selected from polytetrafluoroethylene, modified polytetrafluoroethylene, tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer and tetrafluoroethylene-hexafluoropropylene copolymer 4 The molded product according to 1.
6). The molded product according to 4 or 5, wherein the content of the fluororesin is more than 0% by weight and 30% by weight or less.
7). Furthermore, the molded object in any one of 1-6 containing 1 or more selected from carbon black, carbon fiber, a graphite, an alumina, a titanium oxide, a glass fiber, a glass bead, mica, and molybdenum disulfide.
8). The molded object in any one of 1-7 which is a sealing material.
9. The molded object in any one of 1-8 which is a sealing material for ball valves.
10. The molded product according to any one of 1 to 9, which is a monomer-resistant sealing material.
11. Fill the mold with raw materials containing polyetheretherketone and polymerization inhibitor,
A method for producing a molded article, in which compression molding is performed after room temperature compression molding.
12 12. The method for producing a molded body according to 11, wherein a portion having a thickness of at least 3 mm is removed from an outer surface of the molded body obtained by the compression melt molding.
13. The manufacturing method of the molded object of 11 or 12 which implements the said compression melt molding by covering the outer surface of a raw material or the whole metal mold | die with an oxygen shielding board.
14 The manufacturing method of the molded object of 11 or 12 which implements the said compression melt molding in oxygen reduction or absence.

  ADVANTAGE OF THE INVENTION According to this invention, the molded object which can form a sealing material with a long use period and high creep resistance, and its manufacturing method can be provided.

It is a figure which shows the stress relaxation test apparatus used in the Example.

[Molded body]
The molded article of the present invention contains polyetheretherketone and a polymerization inhibitor.
By including a polymerization inhibitor, it is possible to prevent the monomer from adhering to the molded body and deteriorating the sealing performance even when the molded body is used as a sealing material in a monomer production plant, for example. In addition, when used in a ball valve, the movement of the ball is prevented from being hindered by sticking. For this reason, the use period of a sealing material becomes long, a replacement frequency can be made low, and the operating rate of a plant can be raised.

  Examples of the shape of the molded body include a ball valve seat, packing, gasket, lining, and container.

  The molded article of the present invention is excellent in heat resistance, swelling resistance and chemical resistance and can be used as a sealing material. In particular, in an apparatus for producing a monomer, it can be used as a sealing material (monomer sealing material) used for a member in contact with the produced monomer. Since the molded product of the present invention has excellent creep resistance, it is suitable for use as a ball valve seat.

Hereinafter, the components of the present invention will be described.
1. Polyetheretherketone Polyetheretherketone (PEEK) is a compound having a structure represented by the following formula (1) (wherein n is the number of repetitions).

  By producing a molded body using PTFE, the molded body has excellent creep resistance. Furthermore, when the molded body is used as a sealing material for a monomer production apparatus, the adhesion of monomer aggregates is reduced, and the sealing properties and slip properties are improved. Therefore, it is suitable for use in a portion that is slid while maintaining the sealing property. Further, the mold release after the molding is improved by the inclusion of PTFE, and the manufacturing workability is improved.

  The polyether ether ketone content in the molded body is, for example, 99.99 to 60% by weight, preferably 99.9 to 75% by weight, and more preferably 95 to 90% by weight.

2. Polymerization inhibitor As the polymerization inhibitor, amine compounds (amine polymerization inhibitors), phenol compounds (phenol polymerization inhibitors), and the like can be used, and amine compounds and phenol compounds are preferred.

  In addition to the above, the amine compound is an aromatic secondary diamine compound, N-phenyl-1-naphthylamine, octylated diphenylamine, 4,4′-bis (α, α-dimethylbenzyl) diphenylamine, p- ( p-toluenesulfonylamide) diphenylamine, N, N'-diphenyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N-phenyl-N '-(1,3-dimethylbutyl)- p-phenylenediamine, N-phenyl-N ′-(3-methacryloyloxy-2-hydroxypropyl) -p-phenylenediamine and the like can be used. Further, Nocrack ODA and Nocrack ODA-N (both manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) can also be used.

Examples of the phenol compound include compounds having the following structure.

  The polymerization inhibitor may be one or more selected from the above-mentioned compound group, and is preferably DNPD.

The content of the polymerization inhibitor in the molded body is preferably 0.01 to 10.0% by weight, more preferably 0.05 to 8.0% by weight, still more preferably 0.1 to 5.0%. % By weight.
The content of the polymerization inhibitor in the molded body can be confirmed by gas chromatography mass spectrometry (GC / MS analysis).

Note that the content of the polymerization inhibitor contained in the molded body does not necessarily match the blending amount of the polymerization inhibitor contained in the raw material used for the production of the molded body. This is because, for example, when a molded body is produced by thermoforming, a part of the polymerization inhibitor used as a raw material is changed by thermal decomposition due to heat and oxygen at the time of molding.
For example, it is estimated that the polymerization inhibitor DNPD is thermally decomposed and the structure is changed as follows.

Therefore, the molded article of the present invention preferably contains an unmodified polymerization inhibitor in the above amount. For this purpose, as described later, it is necessary to devise a manufacturing method.
When the molded body contains an unmodified polymerization inhibitor, for example, even when used in a monomer production plant, when the monomer penetrates into the molded body, it effectively prevents polymerization in the molded body, Swells to block the piping, and the molded body itself can be prevented from being destroyed by the swelling. By this, the lifetime of a molded object becomes long, replacement frequency can be made low, and the operation rate of a plant can be raised.

3. Fluorine-based resin When the molded product of the present invention contains a fluorine-based resin, adhesion to a material to be sealed such as a flange (sealability) is improved, which is preferable.

Polytetrafluoroethylene (PTFE), modified polytetrafluoroethylene (modified PTFE), tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and the like. Preferred are polytetrafluoroethylene, modified polytetrafluoroethylene, and tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer, and more preferred is polytetrafluoroethylene.
The polytetrafluoroethylene also includes regenerated polytetrafluoroethylene obtained by forming a molded body once fired into powder.

  The content of the fluororesin in the molded body is, for example, more than 0% by weight and 30% by weight or less. Preferably they are 0.5 weight%-40 weight%, More preferably, they are 2 weight%-20 weight%.

4). Other Components The molded article of the present invention may contain a filler. The degree which does not reduce the penetration resistance of the monomer is preferred. Examples of such fillers include carbon black, carbon fiber, graphite, alumina, titanium oxide, glass fiber, glass beads, mica, and molybdenum disulfide. These fillers can use 1 type (s) or 2 or more types.

  The content of the filler is, for example, 0.1 to 20% by weight, and preferably 0.1 to 5% by weight.

  The molded body of the present invention may consist essentially of PEEK, a polymerization inhibitor, and optionally a fluororesin and the above-mentioned filler (consisting essentially of). For example, 80% by weight or more, 90% by weight or more, 95% by weight or more, or 98% by weight or more of the molded body of the present invention may be PEEK, a polymerization inhibitor, and optionally a fluororesin. In addition, the composition of the present invention may consist of PEEK, a polymerization inhibitor, and optionally a fluororesin (consisting of). In this case, inevitable impurities may be included.

[Method for producing molded article]
The molded body of the present invention can be produced by a method including the following steps (1) to (3).
(1) Polyetheretherketone (preferably 99.99 to 60% by weight, more preferably 99.9 to 75% by weight, still more preferably 95 to 90% by weight) and a polymerization inhibitor (preferably 0.01 to 10%) A step of filling a mold with a raw material containing 0.0 wt%, more preferably 0.1 to 5.0 wt%) (2) The filled raw material is compression-molded (usually at normal temperature) (preferably a surface pressure of 20 ~ 60MPa, more preferably surface pressure 30 ~ 40MPa) (usually 4 ~ 10min) Step (3) compression molding the compression molded body (preferably 300 ~ 400 ° C, more preferably 320 ~ 380 ° C) (preferably 0.05 to 10 MPa, more preferably 0.1 to 5 MPa) (preferably 4 to 30 minutes, more preferably 5 to 10 minutes)

  The obtained molded body can be processed into a desired shape. For example, a cylindrical formed body obtained using a cylindrical mold is machined into a sheet. When using a gasket, it is punched out from the sheet in an annular shape. When using a ball valve, machine (lathe).

  The polymerization inhibitor traps radicals generated in the reaction system, and the polymerization is inhibited by polymerization of the polymerization inhibitor itself to dimerize or cyclize. Therefore, when the raw material is melted or heated in the presence of oxygen at the time of producing a molded body, the polymerization inhibitor is exposed to oxygen and heat, and the polymerization inhibitor is denatured by the radicals and heat of oxygen, so that the radical catch function is achieved. Most are damaged.

  In the above production method, the material containing the polyether ether ketone and the polymerization inhibitor is compression-molded in advance at room temperature or low temperature, the oxygen in the molded body is removed, and then heat-melt molding is performed to modify the polymerization inhibitor. Can be suppressed. However, since the outer surface is easily denatured, the outer surface is preferably removed by machining.

  Also, after the raw material filled in the mold is compression-molded at 20 to 100 MPa at room temperature, the temperature is raised to 250 ° C. while maintaining the pressure at 20 to 100 MPa, and then the temperature is raised while reducing the pressure to compress and melt. If it shape | molds, modification | denaturation of a polymerization inhibitor can be prevented.

  Furthermore, when thermoforming, the raw material is preferably covered with an oxygen shielding plate immediately after being put into the mold and then molded, heated, or molded and heated under reduced oxygen or in the absence of oxygen. Thereby, modification | denaturation of a polymerization inhibitor can be suppressed. Examples of the calcination under reduced oxygen include calcination under nitrogen introduction, and examples of the calcination in the absence of oxygen include calcination in a nitrogen atmosphere.

  In this way, a large amount of unmodified polymerization inhibitor can be present in the finished molded body.

Example 1
Polyetheretherketone and DNPD were mixed with a Henschel mixer to obtain a mixing powder having a DNPD content of 1.0% by weight. The obtained mixed powder is filled in a mold, and compression molded from above and below at a press pressure of 35 MPa at room temperature for 5 minutes, and then the upper and lower press surfaces are heated to 250 ° C. with a heater while maintaining the pressure at 35 MPa, and then the pressure is increased. Then, the upper and lower press surfaces were heated to 370 ° C. After holding at 370 ° C. for 10 minutes, it was gradually cooled to obtain a cylindrical molded body. The obtained cylindrical molding was turned to produce a 1.5 mm thick sheet. In addition, the sheet | seat was manufactured by removing the thickness part of the outer surface 3mm of a molded object.
The following evaluation was performed about the obtained sheet | seat. The results are shown in Table 1.

[Change in weight before and after immersion]
ASTM micro-type dumbbell test pieces were punched out from the obtained sheets to produce immersion test samples. This sample was set in a metal container, and the styrene monomer solution was charged until the sample was completely hidden.
After dipping for 4 hours a day at 100 ° C. under normal pressure, the sample was taken out and dried. The weight of the dried sample after immersion was measured, and the weight increase from the sample before immersion was measured. In addition, the said increase part originates in the solid content produced when the styrene monomer polymerized in the sample.

[Solid styrene peeling]
When the immersion test is performed for 5 days, solidified (polymerized) styrene monomer is deposited on the surface of the test piece. A comparison was made on the ease of removal of the deposits.
Evaluation was made in the following four stages.
Very easy to remove: Easy to remove by hand Easy to remove: Remove somehow by hand Difficult to remove: Can not be removed by hand, peel off with a knife, etc. Have

[Stress relaxation rate]
A sample having a width of 10 mm, a length of 32 mm, and a thickness of 1.5 mm was prepared from the obtained sheet.
Using a stress relaxation test apparatus using a gauge manufactured by JPN Corporation (former Toyo Gauge Co., Ltd.) shown in FIG. 1, according to Nichias Co., Ltd. test standard AS5-6-0087d (stress relaxation test), The relaxation rate was measured and evaluated for creep resistance.
Heated at 100 ° C., 150 ° C. and 200 ° C. for 22 hours, and determined the stress relaxation rate before and after heating.

Test Procedure 1) Clean the surface of the flat disk, and lightly apply low-viscosity oil (CRC5-56No1005 or equivalent product made by Kure Kogyo Co., Ltd.) to the washer and bolt screw.
2) As shown in FIG. 1, the test piece is sandwiched between flat discs, a washer is inserted, and the nut is tightened with fingers.
3) Install a test device fixing jig in a vise, put the bolt head of the test device in the center of the test device fixing jig, and tighten the test device fixing jig in a vise to fix the test device.
4) Screw the dial gauge assembly into the bolt and tighten it with your finger, then move the dial gauge zero adjustment bar up and down several times and adjust the dial gauge outer frame rotation to zero. Set.
5) While confirming the extension of the bolt with the dial gauge, tighten the nut with a dedicated wrench and apply stress to the test piece until the dial gauge reading reaches a predetermined value (D ₀ mm).
6) The method of applying stress with the tightening wrench is applied in one continuous motion within 3 seconds, and the same stress is maintained for about 3 seconds.
7) Remove the dial gauge assembly and heat treat the unit (excluding the dial gauge assembly from the stress relaxation test apparatus in FIG. 1) at 100 ° C., 150 ° C. or 200 ° C. for 22 hours in a hot air circulating furnace.
8) Take out the heat-treated unit from the furnace and forcibly cool it in a test room with a fan for 2.5 hours to bring the unit temperature to the same temperature as the test room temperature (25 ± 5 ° C.). In order to achieve uniform cooling, the position of each unit is changed one hour after the start of cooling.
9) Fix the unit in the vise in the same manner as the procedure in 3) for the forced-cooled unit.
10) Screw the dial gauge assembly into the unit again, tighten it with finger force, and set the dial gauge scale to zero in the same way as 4).
11) Loosen the nut with a dedicated wrench so as not to affect the dial gauge assembly, and read the elongation (D _f mm) of the bolt after heat treatment cooling with the dial gauge.
12) The stress relaxation rate is calculated by the following formula.
Stress relaxation rate (%) = (D ₀ −D _f ) / D ₀ × 100
Wherein, _{D 0:} bolt elongation before the sample heat treatment (mm)
D _f : Bolt elongation after cooling the sample heat treatment (mm)

Example 2
A sheet was prepared and evaluated in the same manner as in Example 1 except that the content of DNPD in the mixed powder used for manufacturing the molded body was 5.0% by weight. The results are shown in Table 1.

Example 3
A sheet was prepared and evaluated in the same manner as in Example 1 except that the mixing powder used in the production of the molded body contained 10% by weight of tetrafluoroethylene (PTFE). The results are shown in Table 1.

Comparative Example 1
DNPD was blended with polytetrafluoroethylene (PTFE) so that the content was 1.0% by weight. After molding at 35 MPa at room temperature, the sheet was fired at 365 ° C. and machined to produce a 1.5 mm thick sheet.
About the obtained sheet | seat, evaluation similar to Example 1 was performed. The results are shown in Table 1.

Comparative Example 2
Using a hot press, blend tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) with 1.0% by weight of DNPD and 0.5% by weight of 2-mercaptobenzothiazole (MBT). The sheet was melt molded at 360 ° C. and machined to produce a 1.5 mm thick sheet.
About the obtained sheet | seat, evaluation similar to Example 1 was performed. The results are shown in Table 1.

Comparative Example 3
Polyetheretherketone was filled in a mold, compression-molded from above and below at a press pressure of 35 MPa at room temperature for 5 minutes, the pressure was lowered to 2 MPa, and then the upper and lower press surfaces were heated to 370 ° C. with a heater. After holding at 370 ° C. for 10 minutes, it was gradually cooled to obtain a cylindrical molded body. The obtained compact was turned to produce a 1.5 mm thick sheet.
The obtained sheet was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 4
A sheet was prepared and evaluated in the same manner as in Comparative Example 3 except that the mixing powder used for manufacturing the molded body contained 10% by weight of tetrafluoroethylene (PTFE). The results are shown in Table 1.

  The molded article of the present invention is suitably used as a sealing material used in piping and valves of petrochemical plants that produce permeable monomers.

Claims (13)

Including polyether ether ketone and radical polymerization inhibitor,
The molded object (however, except a biaxially stretched film) whose said radical polymerization inhibitor is 1 or more selected from an amine type compound and a phenol type compound.   The molded article according to claim 1, wherein the content of the radical polymerization inhibitor is 0.01 to 10% by weight.   Furthermore, the molded object of Claim 1 or 2 containing a fluorine resin.   The fluororesin is at least one selected from polytetrafluoroethylene, modified polytetrafluoroethylene, tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer and tetrafluoroethylene-hexafluoropropylene copolymer. Item 4. A molded article according to Item 3.   The molded product according to claim 3 or 4, wherein the content of the fluororesin is more than 0 wt% and 30 wt% or less.   Furthermore, the molded object in any one of Claims 1-5 containing 1 or more selected from carbon black, carbon fiber, a graphite, an alumina, a titanium oxide, a glass fiber, a glass bead, mica, and molybdenum disulfide.   It is a sealing material, The molded object in any one of Claims 1-6.   It is a sealing material for ball valves, The molded object in any one of Claims 1-7.   The molded article according to any one of claims 1 to 8, which is a monomer-resistant sealing material. It is a manufacturing method of the forming object according to any one of claims 1 to 9,
Polyetheretherketone,
Filling a mold with a raw material containing one or more radical polymerization inhibitors selected from amine-based compounds and phenol-based compounds;
A method for producing a molded article, in which compression molding is performed after room temperature compression molding.   The manufacturing method of the molded object of Claim 10 which removes the part of the thickness to at least 3 mm from the outer surface of the molded object obtained by the said compression-melt molding.   The manufacturing method of the molded object of Claim 10 or 11 which implements the said compression melt molding by covering the outer surface of a raw material or the whole metal mold | die with an oxygen shielding board. The manufacturing method of the molded object of Claim 10 or 11 which implements the said compression melt molding in oxygen reduction or absence.

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