JP2023077352A - Bearing for rubber glove manufacturing device - Google Patents

Abstract

To provide a bearing for a rubber glove manufacturing device that at least has longer service life and is more inexpensive than conventional metal rolling bearings.SOLUTION: A bearing 4 is a resin sliding bearing that is used in a rubber glove manufacturing device that forms a rubber film into a glove mold by immersing the glove mold in a liquid rubber bath to manufacture a rubber glove, and rotatably supports the glove mold. The resin sliding bearing is made of an injection molded body of a resin composition comprising: a layered mineral-based filler which uses polyphenylene sulfide resin as a base resin, and has a Mohs hardness of 3 or less; and a fibrous reinforcement material.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a bearing used in a rubber glove manufacturing apparatus.

Conventionally, a rubber glove manufacturing method and a rubber glove manufacturing apparatus are known.

For example, in Patent Document 1, after holding a glove model in a rubber latex bath, it is pulled up, and then the model is rotated around its longitudinal axis before the adhering latex dries. A method for making rubber gloves is disclosed in which additional rubber latex is added to the glove.

Further, Patent Documents 2 and 3 disclose a rubber glove manufacturing apparatus that rotates and moves a glove mold in a rubber glove manufacturing process.

Bearings are used in the rotating parts of these rubber glove manufacturing apparatuses (hereinafter sometimes referred to as "manufacturing apparatuses") so that the glove mold can rotate smoothly. The lower the frictional torque of the contact portion with the shaft, the smoother the bearing can rotate, which can affect the quality of the manufactured rubber gloves. Conventionally, general metal rolling bearings are used as bearings used in rubber glove manufacturing equipment.

Japanese Patent Publication No. 55-29814 JP-A-48-4148 JP-A-7-148754

In manufacturing equipment, alkaline or acidic liquid rubber (latex), cleaning liquid, hot water, etc. are used in the process, and depending on the process, a high-temperature atmosphere may be used. Prolonged use of glove dies with metal rolling bearings in such an environment can corrode the metal rolling bearings and cause runout of the glove (perpendicular to the longitudinal axis of the glove). vibration) may occur. For this reason, metal rolling bearings may need to be replaced in a relatively short period of time, for example, about 1400 hours of use.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a bearing for a rubber glove manufacturing apparatus that has a longer life than at least conventional metal rolling bearings and is inexpensive.

The bearing for a rubber glove manufacturing apparatus of the present invention (hereinafter also referred to as the bearing of the present invention) is a rubber glove manufacturing method for manufacturing rubber gloves by forming a rubber film on the glove mold by immersing the glove mold in a liquid rubber tank. A bearing used in an apparatus for rotatably supporting the glove mold, comprising a polyphenylene sulfide (PPS) resin as a base resin, a layered mineral filler having a Mohs hardness of 3 or less, and a fibrous reinforcing material. It is characterized by being a resin sliding bearing made of an injection-molded body of a resin composition containing a resin composition.

The resin composition is characterized by containing 40 to 60 parts by mass of the layered mineral filler and 30 to 50 parts by mass of the fibrous reinforcing material with respect to 100 parts by mass of the PPS resin.

The resin composition is characterized by further containing 10 to 30 parts by mass of a solid lubricant with respect to 100 parts by mass of the PPS resin.

The layered mineral-based filler is characterized by containing at least one selected from talc, mica, graphite, and kaolin.

The fibrous reinforcing material is characterized by containing at least one selected from glass fiber, carbon fiber, and aramid fiber.

The bearing for a rubber glove manufacturing apparatus is characterized by being an annealed body of the injection molded body.

The bearing for a rubber glove manufacturing apparatus of the present invention is a resin sliding bearing made of an injection-molded body of a resin composition using PPS resin as a base resin (binding resin with the largest capacity), so it is similar to conventional metal rolling bearings. can be offered at a lower price than Further, this bearing is used in a rubber glove manufacturing apparatus for manufacturing rubber gloves by forming a rubber film on a glove mold by immersing the glove mold in a liquid rubber tank, and is a bearing that supports the glove mold rotatably. Since it is an injection molded product of a resin composition containing a PPS resin, a layered mineral filler having a Mohs hardness of 3 or less, and a fibrous reinforcing material, it has excellent low friction properties and is resistant to liquid rubber and hot water. , Excellent corrosion resistance even in environments where cleaning fluids are used. As a result, the bearing is provided at least at a longer life and at a lower cost than conventional metal rolling bearings.

Since the resin composition contains 40 to 60 parts by mass of a layered mineral filler and 30 to 50 parts by mass of a fibrous reinforcing material with respect to 100 parts by mass of a PPS resin, it has excellent wear resistance in addition to corrosion resistance. , it can be a longer life bearing.

Since the resin composition further contains 10 to 30 parts by mass of a solid lubricant with respect to 100 parts by mass of the PPS resin, the bearing can have excellent low friction characteristics and a longer life.

Since the layered mineral-based filler contains at least one selected from talc, mica, graphite, and kaolin, it can provide a bearing with excellent low-friction characteristics and wear resistance, and a longer service life.

Since the fibrous reinforcing material contains at least one selected from glass fiber, carbon fiber, and aramid fiber, it has excellent mechanical strength and is expected to have a longer life.

Since the bearing for the rubber glove manufacturing apparatus is an annealed injection molded body, the crystallinity of the polymer chain is higher than that of the non-annealed body, and the corrosion resistance, wear resistance, and low friction characteristics are further excellent. .

1 is a schematic diagram of a glove mold used in a rubber glove manufacturing apparatus; FIG. It is a perspective view showing an example of a bearing of the present invention.

A manufacturing process in a rubber glove manufacturing apparatus to which the bearing of the present invention is applied will be described with reference to FIG. FIG. 1 is a schematic diagram of a glove mold used in a rubber glove manufacturing apparatus. The bearing of the present invention is used in a rubber glove manufacturing apparatus for manufacturing rubber gloves by forming a rubber film on the surface of the glove mold 1 by immersing the glove mold 1 in a liquid rubber tank. A shaft 2 having a length of 0.5 to 3 times the length of the glove mold 1 is provided at the center of the glove mold 1 in the longitudinal direction. A bearing member having a bearing of the present invention therein is inserted through the shaft 2 . The bearing member is positioned on the shaft by two retaining rings provided on the outer periphery of the shaft 2 so as to sandwich the bearing member in the axial direction. The bearing rotatably supports the shaft 2 of the glove mold 1 on the inner diameter surface of the cylinder.

The manufacturing process of rubber gloves includes a process of forming a rubber film on a glove mold 1 shaped from a human wrist or upper arm to a fingertip, a process of washing the formed rubber film, and the like. In the step of forming the rubber film, the glove mold 1 is suspended from a rail with the fingertips facing down, and is immersed in a liquid rubber tank filled with liquid rubber. After that, the glove mold 1 is pulled up, placed in a horizontal state, and rotated to dry the liquid rubber with a heater. In the step of washing the rubber film, the glove mold 1 is immersed in a hot water bath, a washing bath, or the like. After that, the glove mold 1 is pulled up, placed in a horizontal state, and rotated while being dried by a heater.

Thus, when the glove mold 1 is immersed in each tank, the glove mold 1 is suspended from the rail, and when the glove mold 1 is dried by the heater, the glove mold 1 is rotated horizontally. . The reason why the glove mold 1 is rotated horizontally is to make the thickness of the rubber film uniform at a predetermined thickness, or to dry the rubber film uniformly.

The bearing member will be described with reference to FIG. FIG. 2 is a perspective view showing one example of the bearing of the present invention. As shown in FIG. 2, the bearing 4 is a cylindrical bush. The bearing 4 is a resin sliding bearing made of an injection-molded body of a predetermined resin composition having a PPS resin as a base resin. As a result, it is less expensive than conventional metal rolling bearings and has excellent corrosion resistance.

Two bearings 4 are used for one glove mold 1 (see FIG. 1), and the two bearings are accommodated in the housing 3 (see FIG. 1). The housing 3 is a cylindrical bearing case. Counterbore holes are formed inside both ends of the housing 3, and bearings are mounted in the counterbore holes. The mounting of the bearing in the counterbore may be mechanical fixation using an adhesive, screws, or the like, or may be fixation by press-fitting or insert molding.

The bearings of the present invention are mounted one each on the upper and lower sides in the axial direction of the glove-shaped shaft. Specifically, the bearings 4 are mounted in counterbore holes at both ends of the housing 3 to form bearing members. The housing 3 has a cylindrical gap between counterbore holes at both ends in which the two bearings 4 are mounted. The inner diameter of the gap is larger than the inner diameter of the bearing 4 and smaller than the outer diameter of the bearing 4 . The inner diameter of the counterbore is approximately the same as the outer diameter of the bearing 4, and the depth of the counterbore (the length in the direction of the rotation axis) is approximately the same as the length of the bearing 4 in the direction of the rotation axis. The inner diameter of the gap is larger than the outer diameter of the glove-shaped shaft, and the inner diameter of the bearing 4 is approximately the same as the outer diameter of the shaft. By providing a constant distance between the bearings in this way, the rotation of the glove mold is more stable.

The shape of the housing is not limited to the shape described above, and may be, for example, a cylindrical member penetrating with a constant inner diameter in the direction of the rotation axis. In this case, only one bearing may be attached to the housing, or a plurality of bearings may be attached. When a plurality of glove molds are mounted, a cylindrical spacer having an inner diameter larger than the inner diameter of the bearing is interposed between the bearings to stabilize the rotation of the glove mold. Further, the housing may be formed with a connecting portion or the like for connecting to the rubber glove manufacturing apparatus. Moreover, the material of the housing is preferably stainless steel from the viewpoint of corrosion resistance and strength.

When a plurality of bearings are attached to the housing, each bearing may be an injection-molded article of the same resin composition, or may be an injection-molded article of a different resin composition. . In the latter case, for example, the No. 1 bearing on the side closer to each tank such as a liquid rubber tank is made to have a composition with a composition that is more excellent in corrosion resistance by increasing the blending ratio of PPS resin, for example, and the No. 1 bearing on the side far from the tank is made. The No. 2 bearing may be made into a bearing having a composition that is more excellent in low-friction characteristics by increasing the blending ratio of the layered mineral filler or blending a solid lubricant. In this case, it is desirable to take preventive measures against incorrect assembly, such as making the outside diameters of the No. 1 and No. 2 bearings different.

The resin composition constituting the bearing of the present invention will be described below. The resin composition used in the present invention contains a PPS resin as a base resin, a layered mineral filler having a Mohs hardness of 3 or less, and a fibrous reinforcing material.

The PPS resin is a crystalline thermoplastic resin having a polymer structure represented by the following formula (1) in which benzene rings are linked by sulfur bonds at para positions. The PPS resin having the structure of the following formula (1) has a melting point of about 280°C and a glass transition point of 90°C. have Depending on its molecular structure, PPS resins are classified into cross-linked, semi-cross-linked, linear and branched types, and in the present invention, they can be used without being limited to these molecular structures and molecular weights.

The resin composition contains a layered mineral filler having a Mohs hardness of 3 or less. If the Mohs hardness is greater than 3, there is concern about aggressiveness to the shaft, and friction torque may increase. More preferably, the layered mineral filler has a Mohs hardness of 1-2.

The Mohs hardness is a scale of hardness in which 10 types of standard substances are scratched sequentially and if a scratch is made, the hardness is judged to be lower than that of the standard substance. The standard substances are, in ascending order of hardness, 1: talc, 2: gypsum, 3: calcite, 4: fluorite, 5: apatite, 6: orthoclase, 7: crystal, 8: topaz, 9: Corundum, 10: diamond. For example, if gypsum (2 on the Mohs hardness scale) does not scratch, but calcite (3 on the Mohs scale) does, the hardness is expressed as 2.5. The Mohs hardness indicates the degree of hardness when force is applied in the lateral direction, and is suitable as a measure of wear on sliding surfaces. The Mohs hardness can be measured using a known Mohs hardness tester.

The layered mineral filler having a Mohs hardness of 3 or less is not particularly limited, and may be talc (Mohs hardness 1), mica (Mohs hardness 3), graphite (Mohs hardness 2), kaolin (Mohs hardness 2), molybdenum disulfide (Mohs hardness Hardness 1) and the like can be used. One or more of these layered mineral fillers may be used. When two or more different Mohs hardnesses are used, it is preferable to mix a compound with a lower Mohs hardness than a compound with a higher Mohs hardness.

The layered mineral-based filler preferably contains at least one selected from talc, mica, graphite, and kaolin. By containing these, the low friction properties and wear resistance are further improved. In particular, the use of talc is preferable because it is effective in preventing abnormal noise. Furthermore, talc and graphite can be used together from the viewpoint of low friction properties and wear resistance.

The content of the layered mineral filler having a Mohs hardness of 3 or less (in the case of multiple types, the total amount; the same shall apply hereinafter) in the resin composition is preferably 30 to 60 parts by mass with respect to 100 parts by mass of the PPS resin. , more preferably 35 to 55 parts by mass, more preferably 40 to 50 parts by mass. Within these ranges, it is easy to achieve both wear resistance and mechanical strength, and desired durability (such as twice or more that of current rolling bearings) can be easily obtained.

When talc and graphite are used together as the layered mineral filler, the ratio of talc:graphite is preferably 2:1 to 20:1 within the above range, and talc:graphite is 3:1 to 10:1. A ratio of talc:graphite=5:1 to 9:1 is more preferable.

As the fibrous reinforcing material used in the present invention, known fibrous reinforcing materials can be used, and one or more of them may be used. The fibrous reinforcing material preferably contains at least one selected from glass fiber, carbon fiber, and aramid fiber. These fibers have chemical resistance and can contribute to improved corrosion resistance.

The content of the fibrous reinforcing material in the resin composition (the total amount in the case of multiple types, the same applies hereinafter) is preferably 30 to 50 parts by mass, preferably 30 to 45 parts by mass, with respect to 100 parts by mass of the PPS resin. and more preferably 35 to 40 parts by mass. By setting the content within these ranges, it becomes easier to achieve both mechanical strength and low friction characteristics.

Considering the above, a particularly preferable form of the resin composition used in the present invention is 40 to 60 parts by mass of the layered mineral filler and 30 to 50 parts by mass of the fibrous reinforcing material per 100 parts by mass of the PPS resin. It is a contained resin composition. When the resin composition has the above composition, it is possible to obtain a bearing that is excellent in corrosion resistance and wear resistance and has a longer life.

Moreover, the resin composition may further contain a solid lubricant. As the solid lubricant, for example, fluororesin powder such as PTFE resin can be used. The solid lubricant is preferably contained in an amount of 5 to 40 parts by mass, more preferably 10 to 30 parts by mass, even more preferably 10 to 23 parts by mass, based on 100 parts by mass of the PPS resin. By containing the solid lubricant within these ranges, low friction characteristics can be improved without impairing wear resistance.

PTFE resin is excellent in heat resistance and has a thermal decomposition temperature of 300° C. or higher, so thermal decomposition during injection molding can be suppressed. In addition, for example, when used without lubrication, a transfer film having excellent self-lubricating properties can be formed on the mating shaft, and low friction characteristics of the bearing can be obtained.

As the PTFE resin used in the present invention, any of molding powder obtained by suspension polymerization, fine powder obtained by emulsion polymerization, and regenerated PTFE may be used, but regenerated PTFE, which has a high lubricating effect, is preferably used. The PTFE resin used in the present invention may be a PTFE resin modified with a side chain group having a perfluoroalkyl ether group, a fluoroalkyl group, or other fluoroalkyl.

The bearing of the present invention may be one obtained by injection-molding the resin composition having the above-described PPS resin as a base resin, and may be a processed body obtained by subjecting the obtained injection-molded body to various treatments. The processed body is preferably an annealed injection molded body. Specifically, the injection molded article after injection molding is preferably annealed (heat treated) for a predetermined period of time at a temperature higher than the glass transition temperature of the PPS resin. As a result, the degree of crystallinity of the polymer chains of the PPS resin is higher than that of the non-annealed body, so that the abrasion resistance and heat resistance are further improved. The heat treatment may deteriorate the shape of the bearing hole, in which case the bearing hole may be finished by reaming after the heat treatment.

The temperature pattern of the annealing treatment is not particularly limited, but a preferable range of the maximum temperature of the annealing treatment is 100.degree. C. to 250.degree. It is more preferably 120°C to 230°C, still more preferably 140°C to 210°C. The annealing treatment time is, for example, preferably 1 hour to 6 hours, more preferably 1 hour to 4 hours, from the viewpoint of achieving both sufficient crystallization at a predetermined temperature and productivity.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples. Table 1 summarizes the composition of the resin composition used in the production of the bearings of each example and each comparative example and the evaluation results of the actual machine durability test.

Using the raw materials shown in Table 1, pellets for injection molding were produced, and the pellets were put into an injection molding machine to obtain bush-shaped (inner diameter φ15 mm, outer diameter φ21 mm, total length 15 mm) bearings (Examples 1 to 3, comparison). Examples 1-3) were prepared. In Example 3 and Comparative Example 3, the injection molded articles (bearings) of Example 2 and Comparative Example 2 were heat-treated at 150° C. for 3 hours. were not heat treated. None of the bearings have reamed bearing holes. Comparative Example 4 is a bearing made of a resin composition containing 100 parts by mass of PTFE resin and 30 parts by mass of glass fiber, and has the same dimensions as those of Example 1. The bearing of Comparative Example 4 is a product turned from a pipe material having an inner diameter of φ13 mm and an outer diameter of φ23 mm.

<Actual Machine Durability Test>
Two of the obtained bearings were mounted in cylindrical housings having an outer diameter of φ28 mm and a total length of 45 mm, each having two counterbore holes at both ends, and used as test bearing members. ). A rubber glove manufacturing apparatus equipped with this test bearing member was operated to manufacture rubber gloves while evaluating the durability of the bearing during actual use. There are two glove dies each fitted with test bearing members, all others using conventional metal rolling bearings. Simultaneously with the start of this durability test, the six glove-shaped metal rolling bearings were replaced with new ones, and the life of the metal rolling bearings was confirmed at the same time.

The rubber glove manufacturing apparatus was operated for up to 1000 hours, and the operation of the glove mold with the test bearing member mounted thereon (glove mold deflection) was visually confirmed to confirm the presence or absence of abnormal operation. Furthermore, the bearing was taken out and the depth of wear of the bearing surface (bearing hole) was measured.

After confirming the state of the bearing surface, the housing is again fitted with a bearing to form a bearing member, the glove mold with the bearing member again fitted is attached to the rubber glove manufacturing apparatus, and the glove is further operated for 1000 hours (total of 2000 hours). The operation of the die was visually confirmed and the wear depth of the bearing surface was measured.

As for the shake of the glove mold, it was judged that the shake occurred when the shake of the rotating glove mold was visually observed, and it was judged that the shake did not occur when the shake was not observed. Regarding the wear depth, “◎” indicates that the wear depth of the bearing surface is 13 μm or less, “○” indicates that it is greater than 13 μm and 25 μm or less, “△” indicates that it is 60 μm or more to 150 μm, and 200 μm or more. It was evaluated with "×". The wear depth of the bearing surface of more than 25 μm to less than 60 μm and more than 150 μm to less than 200 μm were omitted because they were not found in any of Examples 1 to 3 and Comparative Examples 1 to 4. The wear depth is the average value of the wear depths of the bearing surfaces of the two bearings at both ends of the housing. Table 1 shows the results.

As shown in Table 1, as a result of the actual machine durability test on the rubber glove manufacturing apparatus, when the bearings of Examples 1 to 3 were used, no glove-shaped runout was observed after 2000 hours of operation. The wear depth of the bearing surfaces after 2000 hours of operation was also 25 μm or less in all cases, indicating that they could be used continuously. It should be noted that the occurrence of runout in the current metal rolling bearings was about 1400 hours to 1600 hours, and the bearings of Examples 1 to 3 had a longer life than the current bearings.

As for the change in wear depth over time, after 1000 hours of operation, Examples 2 and 3 were "⊚" and Example 1 was "○", and after 2000 hours of operation, Example 3 was "⊚". Examples 1 and 2 were "O". From this result, the durability when the bearing is used in an actual machine is (excellent) (Example 3) > (Example 2) > (Example 1) (poor), and the annealed injection molded body It has been found to be particularly effective.

In actual equipment durability tests using the bearings of Comparative Examples 1 and 4, glove-shaped runout increased by 1000 hours, so the subsequent tests were discontinued. In Comparative Examples 2 and 3, the glove mold did not shake until 1000 hours, but the shaking of the glove mold increased by 2000 hours. In addition, the wear depth of Comparative Example 2 was larger than that of Comparative Example 3.

From the above results, the bearing for the rubber glove manufacturing apparatus of the present invention can be expected to be less expensive than the current metal rolling bearings and have twice or more the durability.

The bearing for a rubber glove manufacturing apparatus of the present invention is excellent in corrosion resistance even in environments where liquid rubber, hot water, cleaning fluid, etc. is used, and is inexpensive. It can be widely used as a long-life slide bearing.

1 glove mold 2 shaft 3 housing 4 bearing (bearing for rubber glove manufacturing device)

Claims (6)

A bearing that is used in a rubber glove manufacturing apparatus for manufacturing rubber gloves by forming a rubber film on the glove mold by immersing the glove mold in a liquid rubber tank, and supporting the glove mold rotatably,
The bearing is a resin sliding bearing comprising an injection-molded body of a resin composition containing a polyphenylene sulfide resin as a base resin, a layered mineral filler having a Mohs hardness of 3 or less, and a fibrous reinforcing material. Bearings for rubber glove manufacturing equipment. 2. The resin composition according to claim 1, wherein the layered mineral filler is 40 to 60 parts by mass and the fibrous reinforcing material is 30 to 50 parts by mass with respect to 100 parts by mass of the polyphenylene sulfide resin. Bearings for rubber glove manufacturing equipment. 3. The bearing for a rubber glove manufacturing apparatus according to claim 2, wherein the resin composition further contains 10 to 30 parts by mass of a solid lubricant with respect to 100 parts by mass of the polyphenylene sulfide resin. The bearing for a rubber glove manufacturing apparatus according to any one of claims 1 to 3, wherein the layered mineral-based filler contains at least one selected from talc, mica, graphite, and kaolin. . The bearing for a rubber glove manufacturing apparatus according to any one of claims 1 to 4, wherein the fibrous reinforcing material contains at least one selected from glass fiber, carbon fiber, and aramid fiber. . 6. The bearing for a rubber glove manufacturing apparatus according to any one of claims 1 to 5, wherein the bearing for a rubber glove manufacturing apparatus is an annealed body of the injection molded body.

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