Method for supporting glass substrate and support pins

Abstract

To provide a method for supporting a glass preform that can reduce the occurrence of cracking and breakage of a seed rod at the top end of the glass preform even when the glass preform is further enlarged, and a support pin having excellent durability and a low frequency of replacement.SOLUTION: A method includes inserting a support pin into a pin insertion hole in a seed rod at the top end of the glass preform and supporting the glass preform by the support pin. The support pin has a metal substrate and a synthetic resin layer coating the surface of the substrate. The synthetic resin layer is provided at a site in contact with at least the pin insertion hole, and the substrate and the synthetic resin layer are fixed at its interface.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a method for supporting a glass base material and a support pin.

Background Art

[0002] Patent Document 1 describes using, as a method for supporting a glass base material and a support pin therefor, a support pin having a synthetic resin coated on the surface of the contact portion with a pin insertion hole, which prevents cracks and breakage from occurring in the seed bar located at the upper end of the glass base material. In this technique, the specific method for coating the synthetic resin layer is to insert a metal support pin base material into a heat-shrinkable synthetic resin tube and then heat the tube to shrink it.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, the glass base materials produced have become even larger, and there has been a demand for a technique that can further reduce the incidence of cracks and breakage in the seed bar compared to the technique disclosed in Patent Document 1. Therefore, an object of the present disclosure is to provide a method for supporting a glass base material that can further reduce the incidence of cracks and breakage in the seed bar located at the upper end of the glass base material even when the glass base material becomes even larger, and in addition, a support pin that is excellent in durability and has a low replacement frequency.

Means for Solving the Problems

[0005] The method for supporting a glass base material of the present disclosure is a method of inserting a support pin into a pin insertion hole provided in a seed bar located at the upper end of a glass base material and supporting the glass base material with the support pin, The support pin comprises a metal base material and a synthetic resin layer covering the surface of the base material, the synthetic resin layer being provided at least in a location that contacts the pin insertion hole, and the base material and the synthetic resin layer being fixed at their interface.

[0006] Furthermore, the support pins of this disclosure are A support pin for supporting the glass base material, which is inserted into a pin insertion hole provided in a seed rod located at the upper end of the glass base material, The device comprises a metal substrate and a synthetic resin layer covering the surface of the substrate, wherein the synthetic resin layer is provided at least in a location that contacts the pin insertion hole, the substrate and the synthetic resin layer are fixed at their interface, and the thickness of the synthetic resin layer is 0.1 mm or more and 0.4 mm or less. [Effects of the Invention]

[0007] According to the glass substrate support method of this disclosure, even if the glass substrate is made larger, the incidence of cracks and breakage of the lead rods of the glass substrate can be further reduced. In addition to the effects described above, the support pin of this disclosure offers high durability of the synthetic resin layer, reducing the frequency of replacement of the support pin itself. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram illustrating an example of the application of the glass substrate support method and support pins of this disclosure in an inspection apparatus. [Figure 2] This is a schematic diagram of a support rod located at the upper end of a glass base material when applying the glass base material support method and support pin described herein. [Figure 3] This is a schematic diagram of the lower end of the suspension rod in the inspection device. [Figure 4] This is a schematic cross-sectional view of the connection point of the suspension rod in the inspection device. [Figure 5] This is a schematic front view of an example of the application of the glass base material support method and support pin of this disclosure in a storage device. [Figure 6]This is a schematic side view of an example of the application of the glass substrate support method and support pin of this disclosure in a storage device. [Figure 7] This is a schematic cross-sectional view of the support pin in the axial direction of the present disclosure. [Figure 8] This is a schematic cross-sectional view of the support pin in the diametrical direction of the present disclosure. [Figure 9] This is a schematic diagram showing the load conditions on the seed rod and support pins when the glass base material support method and support pins of this disclosure are applied. [Figure 10] This is a schematic diagram showing stress concentration and crack formation on the inner surface of the pin insertion hole when a support pin without a synthetic resin layer is used. [Figure 11] This is a schematic diagram showing the stress concentration state on the inner surface of the pin insertion hole when using the support pin of this disclosure. [Modes for carrying out the invention]

[0009] [Description of Embodiments in this Disclosure] First, embodiments of this disclosure will be listed and described. The method for supporting the glass base material in this disclosure is: (1) A method of supporting the glass base material by inserting a support pin into a pin insertion hole provided in a seed rod located at the upper end of the glass base material, The support pin comprises a metal base material and a synthetic resin layer covering the surface of the base material, the synthetic resin layer being provided at least in a location that contacts the pin insertion hole, and the base material and the synthetic resin layer being fixed at their interface. With this configuration, the substrate and the synthetic resin layer are fixed at their interface, so that the synthetic resin layer does not peel off from the surface of the substrate even after long-term use, and the cushioning properties of the support pin surface are maintained. As a result, the load stress applied to the contact portion with the support pin in the support pin insertion hole is reduced, and the incidence of cracks and breakage of the seed rod can be further reduced.

[0010] (2) Preferably, the thickness of the synthetic resin layer is 0.1 mm or more and 0.4 mm or less. According to this configuration, while the synthetic resin layer has sufficient cushioning properties and durability, as the base material, those with a relatively large diameter can be used. Since a base material with a relatively large diameter can be used, the deflection of the support pin during use can be reduced. By reducing the deflection of the support pin, the concentration of stress on the inner surface of the pin insertion hole and the accompanying crack generation can be more effectively suppressed. (3) It is preferable that the synthetic resin layer is formed of a fluororesin. According to this configuration, the synthetic resin layer will be of higher strength, excellent in durability, heat resistance, chemical resistance, and insulation, and further have a high degree of cushioning properties and slipperiness. (4) Also, it is preferable that the synthetic resin is formed of a polyimide resin. According to this configuration, the synthetic resin layer will be of higher strength, excellent in cushioning properties, durability, heat resistance, chemical resistance, and insulation, and further have a high degree of heat resistance.

[0011] The support pin of the present disclosure (5) is a support pin that is inserted into a pin insertion hole provided in a seed bar located at the upper end of a glass base material to support the glass base material, having a metal base material and a synthetic resin layer covering the surface of the base material, the synthetic resin layer being provided at least at a location in contact with the pin insertion hole, the base material and the synthetic resin layer being fixed at their interface, and the thickness of the synthetic resin layer being 0.1 mm or more and 0.4 mm or less. According to this configuration, since the base material and the synthetic resin layer are fixed at their interface, even over long-term use, the synthetic resin layer does not peel off from the surface of the base material, and the cushioning properties of the support pin are maintained. As a result, the load stress applied to the contact portion with the support pin in the support pin insertion hole is alleviated, and the incidence of cracks and breakages in the seed bar can be made lower. Furthermore, the durability of the synthetic resin layer is high, and the replacement frequency of the support pin itself can be reduced.

[0012] [Details of the Embodiment of the Present Disclosure] Hereinafter, examples of glass substrate support methods and support pins according to the embodiments of this disclosure will be described based on the attached drawings. However, the present invention is not limited to these examples, and is intended to include all modifications within the meaning and scope of the claims as shown, and equivalents thereof.

[0013] [Examples of support methods] Examples of applications for the glass substrate support method and support pins described herein include during storage, transport, and inspection of the glass substrate. (Examples of application in inspection equipment) Examples of application in inspection equipment during the inspection of glass base materials will be explained with reference to Figures 1 to 4. In the inspection apparatus 100 shown in Figure 1, the glass base material A to be inspected is supported by suspending it by connecting the upper end of the seed rod 1 to the lower end of the suspension rod 2 via a support pin 10. The lifting and rotating device 3 rotates the suspension rod 2 around a vertical axis D shown by arrow B, for example, while moving it in the vertical direction shown by arrow C, thereby rotating and moving both the seed rod 1 and the glass base material A in the same manner. The glass base material A is inspected by inspection equipment 4, such as an outer diameter measuring instrument, while it is being rotated and moved in the vertical direction.

[0014] This section describes the structure in which the seed rod 1 is supported by the suspension rod 2. As shown in Figure 2, a pin insertion hole 1a is formed at the upper end of the seed rod 1 in a horizontal direction perpendicular to the axis D. The pin insertion hole 1a is a hole for supporting the seed rod 1 on the suspension rod 2, and a support pin 10 is inserted through the pin insertion hole 1a. The inner circumferential surface of the end 1b of the pin insertion hole 1a is chamfered to prevent chipping and so widens outward in a tapered shape. However, the end 1b of the pin insertion hole 1a may not be chamfered.

[0015] As shown in Figure 3, a connecting portion 2a, which is integrally formed with the suspension rod 2, is provided at the lower end of the suspension rod 2. Also, as shown in Figure 4, a recess 2b into which the seed rod 1 is inserted is formed inside the connecting portion 2a. Through holes 2c through which the support pin 10 is inserted are formed at opposing positions on the side wall of the connecting portion 2a. A retaining plate 6 is provided on the outer circumference of the connecting portion 2a to provide auxiliary support for the seed rod 1 inserted into the recess 2b.

[0016] The seed rod 1 is inserted into the recess 2b of the suspension rod 2 so that the insertion hole 2c of the suspension rod 2 and the pin insertion hole 1a of the seed rod 1 are aligned. Then, the support pin 10 is inserted through one of the insertion holes 2c of the suspension rod 2. The support pin 10 is also inserted through the pin insertion hole 1a and the other insertion hole 2c, with both ends protruding slightly from both insertion holes 2c. In this way, the seed rod 1 is suspended from the suspension rod 2 with both ends 10a of the support pin 10 supported by the insertion holes 2c of the suspension rod 2. Furthermore, by tightening the retaining plate 6 with bolts 7, the connecting portion 1a of the seed rod 1 is tightened and fixed between the retaining plate 6 and the inner wall of the recess 2b.

[0017] (Examples of application in storage devices) Examples of applications in storage equipment for glass base materials will be explained with reference to Figures 5 and 6. This application example shows the use of the support method and support pin 10 of this disclosure in a storage device used in a facility for storing glass base material A. Parts common to the above embodiment are denoted by the same reference numerals, and their detailed descriptions are omitted. As shown in Figures 5 and 6, the storage device 40 comprises a support section 41 and a support pin 10. The support section 41 consists of two rods projecting substantially horizontally from the wall surface 42 of a facility or the like. Furthermore, each of these two rods is provided with a recess 41a.

[0018] Next, a method for suspending the seed rod 1 and the glass base material A from the storage device 40 will be described. The support pin 10 is inserted into the pin insertion hole 1a of the seed rod 1 shown in Figure 2 above. Next, both ends of the support pin 10 protruding from the pin insertion hole 1a are placed on the recesses 41a of the support portion 41 (two rods) of the storage device 40. As a result, the glass base material A, which is integrated with the seed rod 1, is suspended and stored while being supported by the support portion 41, as shown in Figures 5 and 6.

[0019] (Support pin 10) The support pin 10, as an example shown in Figures 7 and 8, has a metal base material 11 and a synthetic resin layer 12 that covers the surface of the base material 11. The support pin 10 is fixed at the interface between the base material 11 and the synthetic resin layer 12. In the support pin 10 shown in Figures 7 and 8, the synthetic resin layer 12 is present on the entire surface of the base material 11, but the synthetic resin layer 12 only needs to be provided at a location that contacts the pin insertion hole 1a of the seed rod 1, and it is not necessarily required that the entire surface of the base material 11 be covered with the synthetic resin layer 12.

[0020] The synthetic resin layer 12 of the support pin 10 is not particularly limited as long as it can withstand use as the support pin 10 of this disclosure, but examples include fluororesin, polyimide resin, urethane resin, vinyl chloride resin, and rubber elastic material. Specifically, rubber elastic material refers to a synthetic resin having rubber elasticity such as styrene rubber, butadiene rubber, isoprene rubber, chloroprene rubber, nitrile rubber, fluororubber, urethane rubber, or silicone rubber. Among these, for use as a support pin in this disclosure, fluororesin and polyimide resin are preferred as the material of the synthetic resin layer 12 in terms of having appropriate strength, cushioning, durability, heat resistance, chemical resistance, and insulation properties.

[0021] Furthermore, fluororesin is preferred for the synthetic resin layer 12 because it has even higher cushioning and slipperiness, thereby reducing wear or abrasion at the contact point with the pin insertion hole 1a. Polyimide resin is also preferred because it has even higher heat resistance. The thickness of the synthetic resin layer 12 is appropriately selected considering the weight of the glass base material A to be supported, the inner diameter of the pin insertion hole 1a, and the outer diameter of the base material 11. The thickness of the synthetic resin layer 12 is preferably 0.1 mm or more and 0.4 mm or less, and more preferably 0.1 mm or more and 0.3 mm or less. If the thickness is 0.1 mm or more, sufficient cushioning can be obtained. If the thickness is 0.4 mm or less, the outer diameter of the base material 11 can be increased accordingly, thereby increasing the mechanical strength of the support pin 10 itself. If the mechanical strength of the support pin 10 itself is increased, as will be described in detail later, the deflection of the support pin 10 will be reduced even when a load is applied, and the concentration of stress on the inner wall of the pin insertion hole 1a will also be reduced accordingly.

[0022] The material of the base material 11 of the support pin 10 is not particularly limited as long as it is made of metal that can withstand use as a support pin as described in this disclosure, but examples include stainless steel, brass, steel, aluminum alloy, and titanium. The outer diameter of the base material 11 is appropriately selected considering the weight of the supporting glass base material A, the inner diameter of the pin insertion hole 1a, and the thickness of the synthetic resin layer 12. The outer diameter of the base material 11 is preferably 3 mm or more and 10 mm or less, and more preferably 4 mm or more and 8 mm or less.

[0023] Furthermore, the synthetic resin layer 12 needs to be fixed to the substrate 11 at its interface. In this disclosure, "adhesion" at the interface between the substrate 11 and the synthetic resin layer 12 means that when attempting to separate or peel the substrate 11 and the synthetic resin layer 12 at that interface mechanically or physically, complete separation or peeling is impossible or extremely difficult. To further explain, this "adhesion" also means that when attempting to separate or peel the substrate 11 and the synthetic resin layer 12 mechanically or physically, a portion of the synthetic resin layer 12 remains on the surface of the substrate 11 or the surface of the substrate 11 is significantly damaged. In contrast, the support pin obtained by the technique disclosed in Patent Document 1, in which a metal support pin base material is inserted into a heat-shrinkable synthetic resin tube and then heated to shrink the tube, allows for complete separation of the base material and the synthetic resin at their interface when attempting to mechanically separate them. Even in the state described as "adhered" in this disclosure, complete removal of the synthetic resin layer 12 from the surface of the substrate 11 may be achieved by dissolving the synthetic resin layer 12 with a solvent or chemical, or by burning off the synthetic resin layer 12 by high-temperature heating.

[0024] The technical methods for achieving adhesion of the synthetic resin layer 12 at the interface with the substrate 11 may differ depending on the type of resin constituting the synthetic resin layer 12, and therefore cannot be defined in general terms. Below, we will describe examples using representative types of synthetic resins.

[0025] When a fluororesin is used as the resin constituting the synthetic resin layer 12, adhesion at the interface with the substrate 11 is achieved by baking the fluororesin coating. Any known technique can be applied to bake-on coating of fluororesin onto a metal substrate. For example, the baking coating of fluororesin onto a metal substrate is carried out using the following process.

[0026] 1) Degreasing treatment of the substrate surface To remove any deposits or oils from the surface of the substrate, the substrate is preheated to a predetermined temperature (400°C or higher). 2) Surface roughening treatment of the substrate By treating the substrate with abrasives or etching solutions, an appropriate degree of roughness or an appropriate number and size of pores is formed on the substrate surface. 3) Applying primer to the surface of the substrate Apply a primer to the surface of the substrate. A primer is an adhesive used to bond a highly non-stick fluororesin to a substrate. If a self-adhesive fluororesin paint is used as described later, this primer coating treatment can be omitted. 4) Coating with fluororesin and firing of the coating film The fluororesin coating is applied using air spraying or electrostatic powder coating, and then baked at a predetermined temperature and under predetermined conditions. If necessary, it is preferable to repeat the above coating and baking process multiple times.

[0027] In addition, it is possible to omit either process 2) or 3) above in some cases, but it is preferable to perform both processes. Furthermore, if either process 2) or 3) is omitted, it is preferable to omit process 3) and perform process 2). In the support pin 10 of this disclosure, it is presumed that the adhesion between the substrate 11 and the synthetic resin layer 12 at their interface is largely due to the anchoring effect in which a portion of the primer coating or fluororesin coating penetrates into the recesses or pores of the substrate surface roughened by the treatment in (2) above.

[0028] Furthermore, the process described in 4) above not only "adhesion" at the interface between the substrate 11 and the synthetic resin layer 12, but also polymerization occurs between the coating films or between resin molecules contained in the coating films, causing the synthetic resin layer 12 itself to harden firmly and increase its strength.

[0029] The type of fluororesin used for baking coating is appropriately selected considering the weight of the supporting glass base material A and the inner diameter of the pin insertion hole 1a. Examples of fluororesins that can be used include polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE, CTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), perfluoroalkoxy fluororesin (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), and ethylene-chlorotrifluoroethylene copolymer (ECTFE).

[0030] Next, we will explain the case where polyimide resin is used as the resin constituting the synthetic resin layer 12. When forming a polyimide resin coating layer on the surface of a metal substrate, any known technique can be applied, but the following two methods are the most common. (A) A solution of polyamic acid is used as a coating agent, applied to the surface of the substrate, dried, and then heat-treated to imide the polyamic acid. (B) Electrodeposition coating is performed using a polyimide solution as the electrodeposition solution. Regardless of the method used to form the polyimide resin coating layer, it is preferable to degrease, roughen, and apply a primer to the substrate surface, similar to the fluororesin baking coating described above. The preferred order of selection and the effects of these treatments are also the same as in the case of fluororesin baking coating.

[0031] Next, we will explain the case where urethane resin is used as the resin constituting the synthetic resin layer 12. When forming a urethane resin coating layer on the surface of a metal substrate, any known technique can be applied, but the main methods include immersion of the substrate in a urethane resin solution, spraying of the urethane resin solution onto the substrate surface, brushing, bar coating, knife coating, and so on. Furthermore, in forming the urethane resin coating layer, it is preferable to perform degreasing, roughening, and primer coating of the substrate surface, similar to the fluororesin baking coating described above. The preferred order of selection and the effects of these treatments are also the same as in the case of fluororesin baking coating.

[0032] Next, we will explain the case in which vinyl chloride resin is used as the resin constituting the synthetic resin layer 12. When forming a polyvinyl chloride resin coating layer on the surface of a metal substrate, any known technique can be applied, but the main methods include immersion of the substrate in polyvinyl chloride resin melted by heating, or coating the substrate surface by extrusion. Furthermore, in forming the polyvinyl chloride resin coating layer, it is preferable to perform degreasing, roughening, and primer coating of the substrate surface, similar to the fluororesin baking coating described above. The preferred order of selection and the effects of these treatments are also the same as in the case of fluororesin baking coating.

[0033] Next, we will explain the case in which a rubber elastic material is used as the resin constituting the synthetic resin layer 12. When forming a rubber elastic coating layer on the surface of a metal substrate, any known technique can be applied, but mainly, a coating agent diluted with an organic solvent is applied to the substrate surface by methods such as application, spraying, and dipping, and then heated and dried. Furthermore, in forming the coating layer of the rubber elastic body, it is preferable to perform degreasing, roughening, and primer coating of the substrate surface, similar to the baked coating of fluororesin described above. The preferred order of selection and the effects of these treatments are also the same as in the case of baked coating of fluororesin.

[0034] (Load and stress conditions when using support pins) The load and stress states in the seed rod 1 and support pin 10 when the glass base material support method and support pin of this disclosure are applied are described below. Figure 9 shows a longitudinal section of the connecting portion 2a of the suspension rod 2, where the support pin 10 is passed through the insertion hole 2c of the suspension rod 2 and the pin insertion hole 1a of the seed rod 1. A load M is applied to the support structure due to the weight of the glass base material located at the bottom of the seed rod 1. As shown in Figure 9, when a load M is applied, the support pin 10 bends so that its end side curves upward. If the bent support pin 10 does not have the synthetic resin layer 12 in this disclosure, the support pin 10 will make point contact or line contact with, for example, a corner portion of the pin insertion hole 1a at the upper surface of the support pin 10 shown in the dashed circle H1. Also, at the lower surface of the support pin 10 shown in the dashed circle H2, the support pin 10 will make point contact or line contact with, for example, a corner portion of the connecting portion 2a.

[0035] Therefore, for example, on the upper surface of the support pin 10 shown within the dashed circle H1, stress is concentrated at the contact portion J between the pin insertion hole 1a and the support pin 10, as shown in Figure 10. Also, although not shown in the figure, stress is concentrated on the lower surface of the support pin 10 at the contact portion between the connecting portion 2a and the support pin 10. As shown in Figure 10, when stress concentrates at a specific point on the upper surface of the support pin 10, a crack 1c is likely to form on the inner wall of the pin insertion hole 1a, starting from that point of concentration. Additionally, cracks are likely to form at the connecting portion 2a on the lower surface of the support pin 10.

[0036] However, as shown in Figure 11, the support pin 10 having the synthetic resin layer 12 of this disclosure has a wider contact area R between the pin insertion hole 1a and the support pin 10 due to the cushioning properties of the synthetic resin layer 12. By widening the contact area R between the pin insertion hole 1a and the support pin 10, stress does not concentrate in the contact area R, and cracks are less likely to occur on the inner wall of the pin insertion hole 1a or the connecting portion 2a.

[0037] For glass base materials used in the manufacture of glass fibers and the like, after manufacturing, and before the next processing step, the glass base material is inspected, stored, and transported. This is done by inserting support pins into holes in seed rods or the like located at the upper end of the glass base material, and suspending the ends of the support pins from other suspendable members. Stainless steel (SUS) was mainly used as the material for the support pins. In recent years, the increasing size of glass substrates has led to increased load on the suspension parts of seed rods and other components, causing cracks to form in the pin insertion holes of these components. If these cracks continue to grow, they can cause the seed rods to break, potentially leading to the glass substrate falling. While it might be possible to solve the problem by redesigning the suspension structure itself, modifying both the glass base material and the suspension device would involve a vast scope of work and require large-scale capital investment.

[0038] According to the glass base material support method of this disclosure, the base material 11 of the support pin 10 and the synthetic resin layer 12 are fixed at their interface, so that the synthetic resin layer 12 does not peel off from the surface of the base material 11 even after long-term use, and the cushioning properties of the synthetic resin layer 12 are maintained. As a result, the load stress applied to the contact portion with the support pin 10 in the support pin insertion hole 1a is reduced, and the occurrence rate of cracks and breakage of the seed rod 1 can be further reduced. According to the support pin 10 of this disclosure, in addition to the effects of the support method described above, the synthetic resin layer 12 has high durability and is less prone to deterioration, thus reducing the frequency of replacement of the support pin 10 itself. Furthermore, the glass base material support method and support pin 10 of this disclosure eliminate the need for extensive modifications to the suspension structure.

[0039] [Experimental Example] We evaluated the results when various types of resin were used to constitute the synthetic resin layer 12 of the support pin 10. Furthermore, we compared a case without the synthetic resin layer 12 with a case where the synthetic resin layer was formed by inserting the support pin base material into a heat-shrinkable synthetic resin tube and then heating the tube to shrink it. For the base material 11, a stainless steel (SUS) material was used. In all test examples, the outer diameter was the same. As the synthetic resin layer 12, the following were used: a baked fluororesin coating layer (Test Example No. 1), a polyimide resin (electrodeposition coating) layer (Test Example No. 2), a urethane resin layer (Test Example No. 3), a vinyl chloride resin layer (Test Example No. 4), and a rubber elastic material (silicone rubber) layer (Test Example No. 5). Furthermore, as the synthetic resin layer, Test Example No. 6 was formed by inserting a support pin base material 11 into a heat-shrinkable synthetic resin tube and then heating the tube to shrink it, while Test Example No. 7 was a sample without a synthetic resin layer 12. Test Examples No. 1 to 5 are examples, and Test Examples No. 6 and 7 are comparative examples. In test examples No. 1 to 5, before forming the synthetic resin layer 12, the base material 11 was preheated at 400°C or higher to remove any adhering substances or oils from the surface of the base material. Subsequently, the surface of the base material 11 was roughened to create minute irregularities on the surface of the base material 11.

[0040] For each support pin from Test Examples No. 1 to 7, we evaluated its cushioning properties, heat resistance, and adhesion. The evaluation methods for cushioning, heat resistance, and adhesion were as follows.

[0041] [Cushioning] The hardness of the support pin surface was measured using a hardness tester, and a relative evaluation was performed for each experimental example. The results were ranked from A to G, from best to worst. The results are shown in Table 1 below.

[0042] The known heat resistance temperature of each synthetic resin layer was evaluated relative to the others, and they were ranked from A to G, in descending order of performance. The results are shown in Table 1 below.

[0043] [Adhesion] Relative evaluation was performed by scratching the surface of the support pins with a thin needle to remove the synthetic resin layer. The pins were ranked from A to F, in descending order of resistance to peeling (i.e., greatest adhesion). The results are shown in Table 1 below.

[0044] [Table 1]

[0045] (Evaluation of crack occurrence in seed rod 1 during use) For the glass substrates manufactured over a one-month period, multiple glass substrates were supported using each of the support pins from Test Examples 1 to 7, and then inspected, stored, and transported. Subsequently, the crack occurrence rate on the inner wall of the pin insertion hole 1a of seed rod 1 was evaluated. The support time was kept the same for all evaluations. The crack occurrence rate is a value expressed as a percentage of the number of glass base materials supported by one type of support pin in which cracks occurred on the inner wall of the pin insertion hole 1a of the seed rod 1. Furthermore, the presence or absence of cracks was checked by shining light from the top of seed rod 1 and observing with the naked eye. The results are shown in Table 2 below.

[0046] [Table 2]

[0047] As shown in Table 2 above, when using the support pins in Test Examples No. 1 to 5, the crack occurrence rate was 0.1% or less. When using the support pin in Test Example No. 6, although the cushioning was good, the adhesion was poor, so it is thought that cracks occurred due to deterioration of the resin layer. [Explanation of Symbols]

[0048] 1 seed stick 1a Pin insertion hole 1b end 1c crack 2 Hanging rods 2a Connecting part 2b Recess 2c Through hole 3. Lifting and Rotating Device 4. Inspection equipment 6. Pressing plate 7 volts 10 Support pins 10a Both ends 11 Base material 12 Synthetic resin layer 40 Storage equipment 41 Support part 41a Recess 42 Wall surface 100 Inspection device A glass base material

Claims

1. A method of supporting a glass base material by inserting a support pin into a pin insertion hole provided in a seed rod located at the upper end of the glass base material, The support pin comprises a metal base material and a synthetic resin layer covering the surface of the base material, the synthetic resin layer is provided at least in a location that contacts the pin insertion hole, and the base material and the synthetic resin layer are fixed at their interface. The synthetic resin layer is formed from one of the following: polyimide resin, urethane resin, vinyl chloride resin, and rubber elastic material. The aforementioned fixation is In the case where the synthetic resin layer is a polyimide resin, this is achieved by using a polyamic acid solution as a coating agent, applying the polyamic acid solution to the surface of the substrate, drying it, and then heat-treating it to imide the polyamic acid, or by using the polyimide solution as an electrodeposition solution to perform electrodeposition coating. In the case where the synthetic resin layer is urethane resin, this is achieved by immersing the substrate in a urethane resin solution, or by applying the urethane resin solution to the surface of the substrate by spraying, brushing, bar coating, or knife coating. In the case of the synthetic resin layer being polyvinyl chloride resin, this is achieved by immersing the substrate in polyvinyl chloride resin melted by heating, or by coating the surface of the substrate with polyvinyl chloride resin by extrusion. A method for supporting a glass substrate, wherein, in the case where the synthetic resin layer is a rubber elastic material, the coating agent diluted with an organic solvent is applied to the surface of the substrate by one of the methods of application, spraying, or dipping, and then heated and dried.

2. The method for supporting a glass base material according to claim 1, wherein the thickness of the synthetic resin layer is 0.1 mm or more and 0.4 mm or less.

3. The method for supporting a glass base material according to claim 1 or claim 2, wherein the synthetic resin layer is formed from a polyimide resin.

4. A method for manufacturing a support pin for supporting a glass base material, which is inserted into a pin insertion hole provided in a seed rod located at the upper end of the glass base material, The material comprises a metal substrate and a synthetic resin layer covering the surface of the substrate, wherein the synthetic resin layer is provided at least in a location that contacts the pin insertion hole, the substrate and the synthetic resin layer are fixed at their interface, and the thickness of the synthetic resin layer is 0.1 mm or more and 0.4 mm or less. The synthetic resin layer is formed from one of the following: polyimide resin, urethane resin, vinyl chloride resin, and rubber elastic material. The aforementioned fixation is In the case where the synthetic resin layer is a polyimide resin, this is achieved by using a polyamic acid solution as a coating agent, applying the polyamic acid solution to the surface of the substrate, drying it, and then heat-treating it to imide the polyamic acid, or by using the polyimide solution as an electrodeposition solution to perform electrodeposition coating. In the case where the synthetic resin layer is urethane resin, this is achieved by immersing the substrate in a urethane resin solution, or by applying the urethane resin solution to the surface of the substrate by spraying, brushing, bar coating, or knife coating. In the case of the synthetic resin layer being polyvinyl chloride resin, this is achieved by immersing the substrate in polyvinyl chloride resin melted by heating, or by coating the surface of the substrate with polyvinyl chloride resin by extrusion. A method for manufacturing a support pin, wherein, in the case where the synthetic resin layer is a rubber elastic material, the support pin is manufactured by applying a coating agent diluted with an organic solvent to the surface of the substrate by one of the methods of application, spraying, or dipping, and then heating and drying it.

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