Resin composition and gear

Abstract

A resin composition containing a polyaryl ketone, the resin composition containing a polysiloxane having a structure represented by formula (1), a peak corresponding to a cyclic siloxane being detected in pyrolysis GC / MS of the resin composition, and the content ratio of the polysiloxane in the resin composition being 0.25-1.25 mass%. (In formula (1), R1 and R2 each independently represent an alkyl group having 1-3 carbon atoms)

Description

Technical Field

[0001] This disclosure relates to resin compositions and gears. Background Technology

[0002] Gears and other precision molded products are widely used in the automotive, industrial machinery, and other fields. Examples include precision molded metal products and precision molded resin products. Among these, precision molded resin products possess characteristics such as lightweight, corrosion resistance, and low noise. Therefore, their application in these fields is anticipated.

[0003] For example, Patent Document 1 discloses a resin composition for making gears containing two or more polyetheretherketone resins with different melt viscosities, a fluoropolymer solid lubricant, and aramid fibers.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-134225 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, the inventors have recognized that when using a resin composition containing polytetrafluoroethylene, which is a fluoropolymer-based solid lubricant as described in Patent Document 1, to manufacture precision molded resin articles, deformation sometimes occurs during molding.

[0009] In addition, for precision molded products, the requirement is for precision molded products with few appearance defects.

[0010] The problem of this disclosure is to provide a resin composition that can suppress deformation during the molding of precision molded articles and suppress defects in the appearance of precision molded articles.

[0011] Solution for solving the problem

[0012] This disclosure covers the following content.

[0013] [1] A resin composition containing a polyaryl ketone, the resin composition containing a polysiloxane comprising the structure shown in formula (1) below, wherein a peak corresponding to a cyclic siloxane is detected in the pyrolysis GC / MS of the resin composition, and the polysiloxane in the resin composition is present in a proportion of 0.25 to 1.25 by mass.

[0014] [Chemical Formula 1]

[0015]

[0016] (In equation (1), R) 1 and R2 Each alkyl group independently represents an alkyl group with 1 to 3 carbon atoms.

[0017] [2] According to the resin composition of [1], wherein the polysiloxane in the resin composition is contained in an amount of 0.30 to 1.00 by mass.

[0018] [3] The resin composition according to [1] or [2], wherein the polyaryl ketone is a polyether ether ketone.

[0019] [4] The resin composition according to any one of [1] to [3], wherein the polyaryl ketone has a melt viscosity of 150 to 650 Pa·sec at a temperature of 400°C and a shear rate of 1216 [1 / sec].

[0020] [5] The resin composition according to any one of [1] to [4], wherein the resin composition has a melt viscosity of 380 to 510 Pa·sec at a temperature of 400°C and a shear rate of 1216 [1 / sec].

[0021] [6] The resin composition according to any one of [1] to [5], wherein the number average molecular weight of the polysiloxane is 10,000 to 1,000,000.

[0022] [7] The resin composition according to any one of [1] to [6], wherein the viscosity of the polysiloxane is 1 to 10000 Pa·sec.

[0023] [8] A gear, which is a molded article of a resin composition according to any one of [1] to [7].

[0024] Invention Effects

[0025] According to this disclosure, a resin composition is provided that can suppress deformation during the molding of precision molded articles and suppress defects in the appearance of precision molded articles. Furthermore, a gear is provided as a molded article of the resin composition of this disclosure. Attached Figure Description

[0026] Figure 1 This is an explanatory graph showing the GC / MS results of the pyrolysis of the resin composition.

[0027] Figure 2 It is an explanatory diagram showing the evaluation of the amount of deformation during molding.

[0028] Figure 3 It is an explanatory diagram showing the evaluation of the amount of deformation during molding. Detailed Implementation

[0029] The present disclosure will now be described based on specific embodiments. It should be noted that, in this specification, when the lower limit and upper limit of the numerical range are described separately, the numerical range can be set as any combination of the lower limit and any upper limit.

[0030] As described above, according to the research of the inventors, when gears are molded as precision molded articles using a resin composition containing polytetrafluoroethylene (PTFE) and polyaryl ketone, deformation sometimes occurs during molding. This is believed to be because, for example, in the case of injection molding, the mold temperature is high, causing the molded article to adhere to the mold. In the case of precision molded articles, the contact area between the molded article and the mold is large, thus making such deformation even more likely.

[0031] Therefore, further research was conducted, and it was found that by using a resin composition containing a specified polysiloxane, adhesion to the mold can be suppressed, resulting in suppression of deformation during molding. The reason for this is not yet certain, but the inventors speculate as follows: By containing a polysiloxane with a specified structure in the resin composition, cyclic siloxanes, such as hexamethylcyclotrisiloxane, are generated on the surface of the molded article during molding, improving the demolding and sliding properties of the molded article. As a result, adhesion of the molded article to the mold can be suppressed, and deformation of the molded article during molding can be suppressed.

[0032] The resin composition contains polyaryl ketone.

[0033] There are no particular limitations on the polyaryl ketone used; polyether ketone, polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ketone ether ketone ketone (PEKEKK), etc., can be used. Among them, polyether ether ketone is preferred.

[0034] Polyaryl ketones can be used alone or in combination with two or more.

[0035] The melt viscosity of the polyaryl ketone at a temperature of 400°C and a shear rate of 1216 [1 / sec] is preferably 150–650 Pa·sec, more preferably 200–650 Pa·sec, even more preferably 350–650 Pa·sec, and particularly preferably 450–650 Pa·sec. The melt viscosity can be determined by the method described later.

[0036] By achieving the above-mentioned range, the strength of the resin composition when formed into precision molded articles is further improved. Furthermore, if the melt viscosity is within the above-mentioned range, the crystallization rate (solidification rate) of the polyaryl ketone becomes slower. As a result, it is difficult to adequately cool the molded article, sometimes leading to adhesion of the molded article to the mold. The resin composition disclosed herein provides good mold release even under such conditions, suppressing deformation of the molded article during molding.

[0037] The proportion of polyaryl ketone in the resin composition is not particularly limited, but is preferably 80.00 to 99.75% by mass, more preferably 85.00 to 99.50% by mass, and even more preferably 90.00 to 99.00% by mass.

[0038] The resin composition contains a polysiloxane, which comprises the structure shown in formula (1) below.

[0039] [Chemical Formula 2]

[0040]

[0041] (In equation (1), R) 1 and R 2 Each alkyl group independently represents an alkyl group having 1 to 3 carbon atoms (preferably 1 to 2, more preferably 1).

[0042] As described above, by including a polysiloxane comprising the structure shown in formula (1) in the resin composition, cyclic siloxanes are generated on the surface of the molded article during molding, thereby improving the demolding and sliding properties of the molded article. As a result, adhesion of the molded article to the mold can be suppressed, and deformation of the molded article during molding can be suppressed.

[0043] This is presumably due to the heat resistance of the structure shown in equation (1).

[0044] Typically, as a structural unit of polysiloxanes, R3SiO exists. 1 / 2 The M unit and R2SiO shown 2 / 2 The D unit and RSiO shown 3 / 2 The T unit and SiO shown 4 / 2 The Q unit is shown (R is an organic group such as an alkyl group). Here, the structure shown in the above formula (1) is the D unit.

[0045] If the polysiloxane contains D units, these D units have lower heat resistance compared to Q and T units. Therefore, the D units undergo pyrolysis due to the heat during molding, and a portion of the polysiloxane becomes cyclic siloxanes that improve mold release and sliding properties. As a result, the molded article exhibits improved mold release and sliding properties.

[0046] With Q-units and T-units as the main structural units of the polysiloxane, a three-dimensional network structure is formed, resulting in excellent heat resistance as a polysiloxane. Therefore, such a polysiloxane is not easily pyrolyzed by the heat during molding. As a result, cyclic siloxanes are not fully formed, and the demolding and sliding properties of the molded product are not improved.

[0047] The presence of a polysiloxane comprising the structure shown in formula (1) above in the resin composition can be confirmed by pyrolysis GC / MS. As described above, when the polysiloxane contains a D unit, a peak corresponding to a cyclic siloxane is detected during pyrolysis using pyrolysis GC / MS. Upon confirmation of this peak, it can be confirmed that the resin composition contains a polysiloxane comprising the structure shown in formula (1) above.

[0048] That is, in the resin composition disclosed herein, a peak corresponding to a cyclic siloxane is detected in the pyrolysis GC / MS of the resin composition. The cyclic siloxane is not particularly limited; examples include cyclic dimethyl type cyclic siloxanes, such as trimers like hexamethylcyclotrisiloxane, tetramers like octamethylcyclotetrasiloxane, pentamers like decamethylcyclopentasiloxane, hexamers like dodecylcyclohexasiloxane, heptamers like tetradecylcycloheptasiloxane, and octamers like hexamethylcyclooctasiloxane. Furthermore, low molecular weight cyclic siloxanes such as trimers to icosemers are preferred.

[0049] Peaks corresponding to cyclic siloxanes include, for example, peaks with m / z = 222, 296, 370, 444, 518, and 592. These peaks may contain only one type or multiple types. The peak with m / z = 222 corresponds to hexamethylcyclotrisiloxane, the peak with m / z = 296 corresponds to octamethylcyclotetrasiloxane, the peak with m / z = 370 corresponds to decamethylcyclopentasiloxane, the peak with m / z = 444 corresponds to dodecylcyclohexasiloxane, the peak with m / z = 518 corresponds to tetradecylcycloheptasiloxane, and the peak with m / z = 592 corresponds to hexamethylcyclooctasiloxane.

[0050] The number-average molecular weight of the polysiloxane is not particularly limited, for example, it can be 10,000 to 10,000,000, preferably 100,000 to 10,000,000, more preferably 1000,000 to 10,000,000, and particularly preferably 2,000,000 to 1,000,000. If it is within the above range, the heat resistance of the structure shown in formula (1) becomes more suitable, and it is easier to undergo pyrolysis during molding.

[0051] Furthermore, the viscosity of the polysiloxane is not particularly limited, for example, it can be 1 to 10,000 Pa·sec, preferably 10 to 10,000 Pa·sec, more preferably 100 to 10,000 Pa·sec, even more preferably 1,000 to 10,000 Pa·sec, and particularly preferably 2,000 to 10,000 Pa·sec. If it is within the above range, the number average molecular weight of the polysiloxane is likely to be within the above range as well.

[0052] Furthermore, as a method of containing a polysiloxane comprising the structure shown in formula (1) above in a resin composition, examples include containing EverGlide (registered trademark) manufactured by PolymerDynamix Co., Ltd., and GENIOPLAST (registered trademark) PELLET S manufactured by WackerAsahikasei Silicone Co., Ltd. That is, the resin composition preferably contains one or more of the group consisting of EverGlide (registered trademark) and GENIOPLAST (registered trademark) PELLET S, and more preferably contains EverGlide (registered trademark). As EverGlide (registered trademark), EverGlide (registered trademark) MB3225 is preferred.

[0053] The form of polysiloxane is not particularly limited; for example, forms that are solid at 23°C and one atmosphere can be listed (hereinafter, such polysiloxanes will also be referred to simply as solid polysiloxanes). By including solid polysiloxanes in this way, the pyrolysis of D units caused by the heat during molding can occur more readily and appropriately.

[0054] The polysiloxane content in the resin composition is 0.25 to 1.25% by mass. More preferably, it is 0.30 to 1.00% by mass, and more preferably 0.30 to 0.70% by mass. If the polysiloxane content is less than 0.25% by mass, cyclic siloxanes are not sufficiently generated on the surface of the molded article during molding, making it difficult to improve the demolding and sliding properties of the molded article. Furthermore, if the polysiloxane content exceeds 1.25% by mass, silver streaks may sometimes occur in the molded article, resulting in poor appearance. The reason for the silver streaks sometimes occurring when the polysiloxane content exceeds 1.25% by mass is uncertain, but it is believed that if the polysiloxane content is too high, some of the polysiloxane may undergo pyrolysis during molding, generating gas.

[0055] The proportion of polysiloxane in a resin composition can be determined by extracting polysiloxane from the resin composition.

[0056] The melt viscosity of the resin composition at a temperature of 400°C and a shear rate of 1216 [1 / sec] is preferably 100–550 Pa·sec, more preferably 150–550 Pa·sec, even more preferably 250–550 Pa·sec, particularly preferably 350–550 Pa·sec, and especially more preferably 380–510 Pa·sec. The melt viscosity can be determined by the method described later.

[0057] By achieving the above-mentioned range, the strength of the resin composition when formed into precision molded articles is further improved. Furthermore, if the melt viscosity is within the above-mentioned range, the crystallization rate (solidification rate) of the polyaryl ketone contained in the resin composition becomes slower. As a result, it is difficult to adequately cool the molded article, sometimes leading to adhesion of the molded article to the mold. The resin composition disclosed herein provides good mold release even under such conditions, suppressing deformation of the molded article during molding.

[0058] Furthermore, if the melt viscosity is 380–510 Pa·sec, it is easy to suppress deformation during the molding of precision molded products and to suppress appearance defects in precision molded products.

[0059] The resin composition may contain other additives. Examples of additives include, for example, inorganic fillers, light stabilizers, ultraviolet absorbers, antistatic agents, and pigments.

[0060] The method for manufacturing the resin composition is not particularly limited; for example, it can be manufactured by mixing the aforementioned polyaryl ketone and polysiloxane in a container while heating. That is, the method for manufacturing the resin composition preferably includes a step of heating and mixing the polyaryl ketone and polysiloxane.

[0061] In addition, resin compositions can be manufactured using known methods.

[0062] The resin composition disclosed herein is preferably used in precision molded articles. That is, the resin composition disclosed herein can also be described as a resin composition for precision molded articles, and more specifically, as a resin composition for gears.

[0063] The resin composition can be molded into precision molded articles. Specifically, the resin composition can be molded into gears. By using the resin composition disclosed herein, molded articles in which deformation is suppressed and appearance defects are suppressed can be produced.

[0064] The manufacturing method of the gear is not particularly limited. For example, the resin composition of this disclosure can be molded using any molding method such as extrusion molding, injection molding, compression molding, or vacuum molding. Among these methods, injection molding is preferred.

[0065] The shape of the gear is not particularly limited; for example, the module m can be set to 1.0 to 12.0. The number of teeth can be set to 40 to 65. The tooth width can be set to 5 to 15 mm. The pressure angle can be set to 15° to 25°. The inner diameter φ of the mounting boss can be set to 10.00 to 20.00 mm.

[0066] When using the resin composition disclosed herein, gears having the above-described shape can be readily obtained.

[0067] Moreover, examples of the molded article of the resin composition of the present disclosure include: worm gears, impellers, cams, joints, shafts, bearings, small screws, bolts, nuts, sliding members, connectors, hangers for sliding wires, helical springs, disc springs, snap fasteners, wires for bundling motors, wire meshes, header materials, washers, contact probes, pressure gauges (Bourdon tubes), springs for electronic / electrical equipment, switches, relays, lead frames, diaphragms, bellows, fuse clips, tie straps, bushings, etc.

[0068] Hereinafter, the method for measuring the physical properties of the resin composition will be described.

[0069] <Method for Measuring the Melt Viscosity of Polyarylene Ketone and Resin Composition>

[0070] The melt viscosity of polyarylene ketone and the resin composition is measured according to the following procedure.

[0071] Based on JIS K7199 (ISO 11443), the melt viscosity of polyarylene ketone and the resin composition is measured under the conditions of a temperature of 400 °C and a shear rate of 1216 [1 / s].

[0072] <Pyrolysis GC / MS of Resin Composition>

[0073] The pyrolysis GC / MS of the resin composition is measured according to the following procedure.

[0074] Weigh 1 mg of the resin composition as the measurement material, perform pyrolysis under the following pyrolysis conditions, and then perform GC / MS measurement under the following GC / MS measurement conditions.

[0075] <Pyrolysis Conditions>

[0076] Apparatus: Frontier Lab EGA / PY-3030D.

[0077] Pyrolysis conditions: 400 °C for 10 min.

[0078] Interface: 320 °C.

[0079] <GC / MS Measurement Conditions>

[0080] GC / MS: GCTOFMS / Agilent GC7890B manufactured by JEOL.

[0081] Inlet temperature: 320 °C.

[0082] Column: DB-5MS 30 m - 0.25 mm I.D. - 0.25 μm.

[0083] Carrier gas: He, 1 ml / min, constant flow.

[0084] Oven: Maintain at 40℃ for 2 min, then increase the temperature to 300℃ (13 min) at a rate of 20℃ / min.

[0085] Interface: 300℃.

[0086] Split ratio: 50 / 1.

[0087] MSD: EI / Scan, ion source: 230℃.

[0088] m / z: 10~800.

[0089] The various components and combinations in each embodiment are merely examples, and appropriate additions, omissions, substitutions, and other modifications to the components can be made without departing from the spirit of the invention. This disclosure is not limited to the embodiments but only to the claims.

[0090] Example

[0091] The present disclosure will now be described in detail with reference to embodiments. However, the present disclosure is not limited to the embodiments described below.

[0092] [Example 1]

[0093] 100 parts by weight of polyetheretherketone (manufactured by Polyplastics-Evonik, trade name: VESTAKEEP (registered trademark) 5000G) and 1.2 parts by weight of EverGlide (registered trademark) MB3225 (manufactured by PolymerDynamix) were dry-mixed beforehand, and then mixed at 380°C using a twin-screw extruder with L / D=40 and L:40mm to obtain a resin composition. MB3225 is a masterbatch containing 25% by weight of polyetheretherketone and polysiloxane as the base resin.

[0094] Gears were obtained by injection molding after hot melting of the resin composition. The gear properties were set as follows: module m = 1.0, number of teeth 54, tooth width 10 mm, pressure angle 20°, and inner diameter of the mounting boss φ13.25 mm. A FANUC ROBOSHOT S-2000i-100B molding machine was used. Molding conditions were set as follows: resin temperature: 400°C, mold temperature: 200°C, injection speed: 20 mm / s, holding pressure: 120 MPa, holding time: 15 seconds, cooling time: 40 seconds, and ejector pin ejection delay upon mold opening: 30 seconds. The obtained gears were evaluated as follows.

[0095] Furthermore, the results obtained by pyrolysis GC / MS of the resin composition using the above method are shown below. Figure 1 .like Figure 1As shown, a peak corresponding to cyclic siloxanes was confirmed.

[0096] Furthermore, the melt viscosity of the resin composition was determined using the above method, and the melt viscosity was found to be 500 Pa·sec.

[0097] <Evaluation of Top Load>

[0098] During gear injection molding, the ejection load during extraction from the mold is measured based on the ejection load waveform of the molding machine. The minimum value (%) is read from the waveform during ejection, and its absolute value is taken as the ejection load value. A small ejection load indicates excellent demolding and sliding properties of the gear.

[0099] <Evaluation of Deformation During Molding>

[0100] The deformation during molding was evaluated using a VR-3200 One-shot 3D shape measuring machine manufactured by KEYENCE.

[0101] With the protruding surface of the gear on the top, the application is used to capture the total length (diameter) of the gear. The focus is on the web portion, and images are captured simultaneously through continuous measurement. Figure 2 A).

[0102] In the analysis application, the profile tool is used to define a straight profile from the profile measurement window, including the center of the gear. Figure 2 B). Then, using the "line-point" measurement mode in the "measuring tools" tool, draw a baseline on the web. Figure 2 The part of the boss in C, marked with ×, is taken as a point. The distance between the baseline and the point (i.e., the distance between the baseline and the boss) is measured at two points. Figure 2 (C's × part). Calculate the value of the average of the two points [mm], rounding the second decimal place to the first decimal place, and use this value as the deformation amount during molding.

[0103] <Gear Appearance Evaluation>

[0104] The appearance evaluation of gears is conducted visually. The evaluation criteria are as follows. Here, silver streaks refer to the phenomenon of gas or air appearing on the surface of the molded part; the presence or absence of silver streaks is confirmed on the web portion of the molded part.

[0105] A: No silver lines were detected by visual inspection.

[0106] B: The silver lines were confirmed by visual inspection.

[0107] [Examples 2-3]

[0108] The amount of EverGlide (registered trademark) added was varied so that the proportion of polysiloxane in the resin composition was as shown in Table 1. Otherwise, the resin composition and gear were obtained in the same manner as in Example 1. The evaluation results are shown in Table 1. Here, the resin compositions of Examples 2 and 3 were also subjected to pyrolysis GC / MS, and the results confirmed the peaks corresponding to cyclic siloxanes in the same manner as in Example 1.

[0109] [Comparative Examples 1-7]

[0110] The types of polyetheretherketone (PEEK) and additives were set to those listed in Table 1, and the proportion of polysiloxane in the resin composition was changed to the values ​​in Table 1. Otherwise, the resin composition and gear were obtained in the same manner as in Example 1. The evaluation results are shown in Table 1. For the gear of Comparative Example 1, the amount of deformation during molding was evaluated in the same manner as in Example 1, and the results are shown in Table 1. Figure 3 . Figure 3 A shows the captured image, and... Figure 2 A corresponds to. Figure 3 B shows the outline of the defined straight line, and... Figure 2 B corresponds to. Figure 3 C shows the two-point measurement of the distance between the baseline and the point, and... Figure 2 C corresponds. According to... Figure 3 It is also clear that in Comparative Example 1, gear deformation occurred during molding.

[0111] In Comparative Examples 2, 3, and 5-7, where the type of polyetheretherketone was the same as in Example 1, gear deformation occurred during molding, just as in Comparative Example 1.

[0112] Furthermore, the results obtained by pyrolysis GC / MS of the resin compositions of Comparative Example 5 and Comparative Example 6 are shown below. Figure 1 .like Figure 1 As shown, no peak corresponding to cyclic siloxanes was identified. The same results were obtained for Comparative Examples 1, 2, and 7.

[0113] [Table 1]

[0114]

[0115] In Table 1, L4000G represents VESTAKEEP (registered trademark) L4000G manufactured by Polyplastics-Evonik, 5000G represents VESTAKEEP (registered trademark) 5000G manufactured by Polyplastics-Evonik, EG represents EverGlide (registered trademark) MB3225, PTFE micro powder represents Dyneon PTFE micro powder TF9205 manufactured by 3M, silicone resin powder 1 represents silicone resin powder KMP-590 manufactured by Shin-Etsu Chemical Co., Ltd., and silicone resin powder 2 represents silicone resin powder X-52-854 manufactured by Shin-Etsu Chemical Co., Ltd. Furthermore, regarding the amount of additives added, when the additive is MB3225, MB3225 is added in such a way that the amount of polysiloxane contained in MB3225 is equal to the value in Table 1. For other additives, the amounts listed in Table 1 are added.

[0116] Industrial availability

[0117] According to this disclosure, a resin composition can be provided that can suppress deformation during the molding of precision molded articles and suppress defects in the appearance of precision molded articles. Furthermore, a gear can be provided as a molded article of the resin composition of this disclosure.

Claims

1. A resin composition comprising a polyaryl ketone, The resin composition contains polysiloxane. The polysiloxane comprises the structure shown in formula (1) below. In the pyrolysis GC / MS of the resin composition, peaks corresponding to cyclic siloxanes were detected. The polysiloxane in the resin composition is present in an amount of 0.25–1.25% by mass. In equation (1), R 1 and R 2 Each can be used to independently represent an alkyl group having 1 to 3 carbon atoms.

2. The resin composition according to claim 1, wherein, The polysiloxane in the resin composition is present in an amount of 0.30 to 1.00% by mass.

3. The resin composition according to claim 1 or 2, wherein, The polyaryl ketone is a polyether ether ketone.

4. The resin composition according to any one of claims 1 to 3, wherein, The polyaryl ketone has a melt viscosity of 150–650 Pa·sec at a temperature of 400°C and a shear rate of 1216 [1 / sec].

5. The resin composition according to any one of claims 1 to 4, wherein, The resin composition has a melt viscosity of 380–510 Pa·sec at a temperature of 400°C and a shear rate of 1216 [1 / sec].

6. The resin composition according to any one of claims 1 to 5, wherein, The number average molecular weight of the polysiloxane is 10,000 to 10,000,000.

7. The resin composition according to any one of claims 1 to 6, wherein, The viscosity of the polysiloxane is 1–10000 Pa·sec.

8. A gear, which is a molded article of the resin composition according to any one of claims 1 to 7.

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