JP2005014489A - Mold and method for manufacturing roller member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for manufacturing a roller member which can reduce a force required for releasing it from the mold, even when the mold is used in monolithic molding technique substantially under pressure and also can manufacture a high precision roller member with high yield, and a method for manufacturing the roller member using the mold. <P>SOLUTION: This mold for manufacturing the roller member is of a drum type and used in a molding process for integrally molding a foam layer on the outer periphery of a shaft by the foaming and curing of a liquid raw material. In at least a region, where the inner peripheral surface comes into contact with the foam layer, of the latter, a coating layer 3 in which a resin particle 2 containing a fluororesin is dispersed in a tetrafluoroethylene-hexafluoropropylene copolymer as a base resin 1, is formed. In addition, the particle diameter of the resin particle 2 is larger than the maximum film thickness of the base resin 1 in the coating layer 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００５２】
【発明の効果】
以上説明してきたように、本発明によれば、特に、実質的に加圧下で一体成形を行う手法に用いる場合でも、脱型時に要する力を低減することができ、高性能のローラ部材を歩留よく製造することができるローラ部材製造用金型、および、それを用いたローラ部材の製造方法を実現することができる。
【図面の簡単な説明】
【図１】本発明の一例のローラ部材製造用金型を示す概略斜視図である。
【図２】図１のローラ部材製造用金型の内表面近傍を示す拡大部分断面図である。
【図３】（イ）、（ロ）は、本発明に係るローラ部材の製造装置を示す概略断面図である。
【図４】（イ）、（ロ）は、夫々図３中のＡ−Ａ’線、Ｂ−Ｂ’線に沿う断面図である。
【図５】実施例におけるローラ部材の脱型力測定に係る説明図である。
【図６】引っ張り圧縮試験機におけるローラの移動距離と脱型力との関係を表すローラ脱型時の荷重曲線のグラフである。
【図７】実施例および比較例の脱型回数と脱型力との関係を示すグラフである。
【符号の説明】
１ ベース樹脂（ＦＥＰ樹脂）
２ 樹脂粒子
３ コーティング層
１０ 金型
１１ 内周面
１２ 軸
１３ａ，１３ｂ 栓状部材
１４ａ，１４ｂ 圧入部
１５ａ 上方端部
１５ｂ 下方端部
１６ キャップ部材
１７ ベントホール
１８ 上部キャップ
２０ 注入ノズル[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller member manufacturing mold (hereinafter also simply referred to as “mold”) used in an image forming apparatus and the like and a roller member manufacturing method. The present invention relates to a roller member manufacturing die used in a method of integrally forming a shaft and a foam layer by pouring and heat-curing, and a method of manufacturing a roller member using the same.
[0002]
[Prior art]
In electrophotographic apparatuses and electrostatic recording apparatuses such as copying machines, printers and facsimiles, developing rollers, toner supply rollers, and cleaning rollers are used in each process of development, toner layer formation, cleaning, paper feeding, and conveyance in the electrophotographic process. Various roller members such as a paper feed roller and a conveyance roller fulfill various frame ratios.
[0003]
These roller members have a structure in which an elastic body layer made of a rubber material or a resin material is supported on the outer periphery of the shaft. In particular, the elastic body layer is made of a foam made of a low-elastic polymer elastic foam. Many formed roller members having a foam layer are used. In a roller member provided with such a foam layer, it is important that the foam layer has a fine and uniform cell structure over the entire member, thereby achieving uniform hardness.
[0004]
As a method of manufacturing such a roller member, a method of forming a foam layer by integral molding with a shaft using a mold in which a shaft is previously arranged is generally used. In order to obtain good roller performance, various methods are available. Manufacturing methods have been studied and proposed. Among them, from the viewpoint of ease of post-processing and the like, a method of obtaining a final shape as a roller member by molding using a cylindrical mold has become the mainstream recently.
[0005]
In such a mold, it is well known that the inner surface is coated with a fluororesin or the like to impart releasability. For example, polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene Various fluororesin materials such as a polymer (FEP) and a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) are used as a coating material. For example, Patent Document 1 and Patent Document 2 describe the technique related to the coating of the mold, and the present applicant has also proposed a technique related to the improvement of the coating (see, for example, Patent Document 3). ).
[0006]
[Patent Document 1]
JP-A-7-80876 (claims, etc.)
[Patent Document 2]
JP-A-10-15976 ([0016] etc.)
[Patent Document 3]
JP 2002-326239 A (Claims etc.)
[0007]
[Problems to be solved by the invention]
As a result of studying the roller member manufacturing method using the above-described mold, the present inventors have found that a mold is formed immediately after liquid raw material injection in order to achieve a fine and uniform cell structure and uniform hardness. It has been found that it is effective to perform heat-curing in a state where the mold is sealed and the pressure is substantially applied to the inside of the mold. However, it has been found that when this method is used, a new problem arises that the force required for demolding becomes very large.
[0008]
In the conventional manufacturing method, by using a mold to which the above-described conventional fluororesin coating is applied, it is possible to remove the obtained roller member without any problem and about 0.5 N at the maximum. I was able to demold with the power of. However, in the case of a roller member obtained by molding under pressure, a force of about 5 to 10 N, which is about 10 to 20 times the conventional value, is required at the time of demolding. In some cases, manufacturing defects such as falling off occurred.
[0009]
Accordingly, an object of the present invention is to reduce the force required at the time of demolding even when used in a method of performing integral molding substantially under pressure, and to produce a high-performance roller member with high yield. An object of the present invention is to provide a roller member manufacturing die excellent in releasability and a method for manufacturing a roller member using the same.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventors have intensively studied various coating materials such as PTFE, PFA, FEP and the like. As a result, the following configuration is used for integral molding under pressure. Even in such a case, it has been found that the mold can be easily removed with a small force, and a high-performance roller member can be produced with a high yield, and the present invention has been completed.
[0011]
In order to solve the above problems, the roller member manufacturing die of the present invention has a cylindrical shape, and is a roller used in a molding process in which a foam layer is integrally formed on the outer periphery of a shaft by foaming and curing of a liquid raw material. In molds for manufacturing parts,
A coating layer formed by dispersing resin particles containing a fluororesin in a tetrafluoroethylene-hexafluoropropylene copolymer as a base resin is formed on at least a region of the inner peripheral surface that is in contact with the foam layer, The particle diameter of the resin particles is larger than the maximum film thickness of the base resin in the coating layer.
[0012]
As the resin particles, those made of PTFE can be preferably used. The particle diameter of the resin particles is preferably not more than 3 times the maximum film thickness of the base resin. Furthermore, the film thickness of the base resin is preferably 5 to 10 μm.
[0013]
The roller member manufacturing method of the present invention is a method in which a foamed liquid raw material is poured into the mold, heated and hardened in a state where the shaft penetrates the center line of the cylindrical mold. Thus, in the roller member manufacturing method including a molding step of forming a foam layer on the outer periphery of the shaft, the roller member manufacturing mold according to the present invention is used as the mold. .
[0014]
In the production method of the present invention, immediately after injecting a predetermined amount of the liquid raw material into the mold, both ends of the mold are closed and the liquid raw material is heated while the mold is sealed. It is more effective when curing. In particular, it can be suitably applied to the production of a polyurethane foam roller member using a polyurethane raw material as the liquid raw material.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific embodiments of the present invention will be described in detail.
In FIG. 1, the schematic perspective view of the metal mold | die 10 for roller member manufacture of this invention is shown. As shown in the figure, the mold 10 of the present invention has a cylindrical shape, and is used in a molding process in which a foam layer is integrally formed on the outer periphery of a shaft by foaming and curing a liquid raw material.
[0016]
FIG. 2 shows an enlarged partial sectional view of the vicinity of the surface of the inner peripheral surface 11 of the mold 10. As shown in the figure, a coating layer 3 in which resin particles 2 containing a fluororesin are dispersed in FEP as a base resin 1 is formed on the inner peripheral surface 11 of the mold 10. The coating layer 3 has a particle diameter larger than the maximum film thickness of the FEP resin 1.
[0017]
That is, when the maximum film thickness of the FEP resin 1 in the coating layer 3 is A and the particle diameter of the resin particles 2 is B, the following formula is given between A and B:
A <B
The relationship expressed by As shown in the drawing, in this way, in the coating layer 3, the resin particles 2 protrude from the surface of the FEP resin 1 serving as a base. Therefore, due to the effect of the resin particles 2, the releasability can be remarkably improved as compared with the case of a single coating layer such as a conventional FEP resin, and the demolding force is reduced to a practical level. be able to. When the particle diameter B of the resin particles 2 is equal to or less than the maximum film thickness A of the FEP resin 1, the dispersion effect of the resin particles 2 cannot be obtained and the demolding force cannot be reduced. Further, although there are various types of resin materials used as coating materials, according to the study by the present inventors, by using resin particles containing FEP resin and fluororesin as a combination of base resin and dispersed particles, No releasability improvement effect can be obtained.
[0018]
In particular, between the maximum film thickness A of the FEP resin 1 and the particle diameter B of the resin particles 2, the following formula:
B ≦ 3A
It is preferable that the relationship represented by If the particle diameter B is larger than 3 times the maximum film thickness A, the effect of reducing the demolding force can be obtained, but the resin particles 2 can easily fall out of the FEP resin 1, and the coating layer 3 Durability will be reduced.
[0019]
Although it does not specifically limit as a material of the resin particle 2, It is necessary to contain a fluororesin, and it is preferable to consist of a fluororesin especially. Examples of such a fluororesin include PTFE, HFP-TFE-VDF (hexafluoropropylene-tetrafluoroethylene-vinylidene fluoride), PE-PTFE and PVdF (polyvinylidene fluoride). It is particularly preferable to use the resin particles.
[0020]
The coating layer 3 is provided at least in a region of the inner peripheral surface 11 of the mold 10 that is in contact with the foam layer, that is, a region corresponding to a portion that is filled with the liquid raw material when the mold is used. , Provided in the entire inner peripheral surface area of the mold 10. Thereby, the reduction effect of demolding force can be acquired. The film thickness of the FEP resin 1 as the base resin in the coating layer 3 is preferably 5 to 10 μm. If this film thickness is too thin, sufficient releasability cannot be obtained. On the other hand, if it is too thick, no further effect can be expected, and the cost is deteriorated. Therefore, the suitable range of the particle diameter B of the resin particle 2 that satisfies the above conditions is about 20 to 30 μm. Furthermore, the addition amount of the resin particles 2 with respect to the FEP resin 1 as the base resin can be about 5 to 20% by weight, preferably about 10% by weight. If the addition amount of the resin particles 2 is too small, the desired effect of reducing the demolding force cannot be obtained. On the other hand, if the addition amount is too large, no further effect can be expected, and the cost is deteriorated.
[0021]
The material of the mold 10 is not particularly limited, and in addition to metals such as iron, copper, aluminum, and stainless steel, ceramics can be used, but stainless steel is the most suitable in terms of strength, cost, etc. It is. Moreover, there is no restriction | limiting in particular also in the formation method of a coating layer, For example, techniques, such as spray coating, can be used.
[0022]
The method for producing a roller member according to the present invention comprises injecting a liquid raw material previously foamed into a mold with the shaft penetrating on the center line of a cylindrical mold, and heating and curing the shaft. In the molding step of forming the foam layer on the outer periphery of the metal, other manufacturing conditions and the like are not particularly limited as long as the mold 10 of the present invention is used. it can.
[0023]
In particular, in the manufacturing method of the present invention, immediately after a predetermined amount of liquid raw material is injected into the mold 10, the opening of both ends is closed and the liquid raw material is heated and cured in a state where the mold 10 is sealed. It is effective when using the technique to do. Since the liquid raw material inside the closed mold is cured under a substantially pressurized state, free expansion of the liquid raw material at the time of curing is suppressed, the cell diameter is small, and the cell diameter and Although a foam layer with less variation in hardness is formed, on the other hand, since it is compressed in the mold, a very large force is required for demolding. By applying the technique of the present invention to this method, the force required for demolding the compressed foam layer can be reduced, and a high-performance roller member can be easily manufactured.
[0024]
In order to perform the molding process in the sealed state as described above, for example, a roller member manufacturing apparatus as shown in FIG. 3 can be used. The apparatus shown in the figure includes a mold 10 of the present invention as a main body, and includes plug-like members 13a and 13b that are respectively attached to both ends of a shaft 12 disposed on the center line thereof, and these plug-like members 13a and 13b. Are formed in a shape capable of substantially closing the corresponding both-end openings of the mold 10. In the illustrated example, the upper plug-like member 13a is press-fitted into the press-fit portion 14a, and the lower plug-like member 13b is press-fitted into the press-fit portion 14b.
[0025]
Here, the press-fitting portion 14 b into which the lower plug-like member 13 b is press-fitted is formed by the inner peripheral surface of the cap member 16 having a substantially cylindrical shape inserted into the lower end portion 15 b of the mold 10. That is, as shown in the drawing, the inner peripheral surface of the cap member 16 is formed in a stepped shape with a decreasing inner diameter from the upper side to the lower side, and the corresponding plug-like member 13b is fitted on the inner peripheral surface of the maximum diameter. The plug-like member 13b can be press-fitted as the press-fitting portion 14b on the other inner peripheral surface. The step shape is formed in at least three steps as shown in the drawing in order to smoothly perform the sealing operation described later.
[0026]
4A is a cross-sectional view taken along the line AA ′ in FIG. 1A, that is, the inner peripheral surface of the cap member 16 having the maximum diameter. As shown in the drawing, a longitudinal groove-shaped vent hole 17 is provided on the inner peripheral surface of this portion of the cap member 16. By providing the vent hole 17, the flow of the liquid material to be injected can be made smooth to prevent the occurrence of air accumulation, and the mold 10 can be reliably filled with the liquid material. Further, when the mold 10 is filled with the liquid material, the liquid material starts to flow out of the vent hole 7 instead of air. Therefore, the mold 10 can be sealed with the start of the flow of the liquid material as a signal. it can. It is preferable to provide the vent holes 17 at regular intervals in the circumferential direction of the cap member 16, and in particular, as shown in the figure, at least four vent holes 17 are provided at regular intervals in the circumferential direction, so that the occurrence of air accumulation is more effective. Therefore, the mold 10 can be filled with the liquid raw material more uniformly and smoothly.
[0027]
In the illustrated example, a substantially cylindrical upper cap 18 is attached to the upper end 15a of the mold 10, and the inner peripheral surface of the upper cap 18 is press-fitted into the plug-like member 13a. Part 14a is formed. The upper cap 18 has an inner diameter corresponding to the diameter of the injection nozzle in the upper part, has an inner diameter in which the stopper member 13a can be press-fitted in the lower part, and engages the stopper member 13a with the mold 10 sealed. There are no particular restrictions on the shape, structure, material, etc., as long as it can be stopped. Similarly, the plug-like members 13a and 13b and the cap member 16 are not particularly limited as long as the above-described conditions are satisfied. As a material of these members, for example, a resin material such as polypropylene (PP) can be used.
[0028]
As a procedure for sealing the mold 11 with the shaft 12 immediately after the liquid raw material is injected using the apparatus shown in the figure, first, as shown in FIG. 3 (a), the plug-like member 13b below the shaft 12 is a cap member. In the state where it is inserted into the maximum inner diameter surface of 16 (corresponding to the AA ′ cross section shown in FIG. 4 (a)), it is pre-foamed from the upper opening to the inside of the mold 10 using the injection nozzle 20. Inject liquid raw material. At this time, the plug-like member 13a above the shaft 12 is in a free state, and the shaft 12 is supported only by the lower plug-like member 13b.
[0029]
When the liquid raw material is filled in the mold 10 and the liquid raw material starts to flow out of the vent hole 17 (see FIG. 4A), the cap member 16 is pushed up to start sealing the mold 10. When the cap member 16 is pushed up, the shaft 12 is pushed up together with the cap member 16, so that the plug-like member 13a above the shaft 12 is press-fitted into the press-fitting portion 14a via the shaft 12, and is first on the liquid material injection side. The upper opening of the mold 10 is closed. When the cap member 16 is further pushed up, the lower plug-like member 13b then moves in the cap member 16 and from the maximum diameter inner peripheral surface (cross section AA ′ in FIG. The other inner peripheral surface with a small diameter (cross section BB ′ in FIG. 3 (a), press-fitting portion 14b) is pushed in (see FIG. 3 (b)). As shown in FIG. 4B, since no vent hole is provided in the inner peripheral surface corresponding to the BB ′ cross section of the cap member 16, the plug-like member 13b is press-fitted into the press-fit portion 14b. As a result, the lower opening of the mold 10 is also substantially closed, thereby sealing the mold 10. Thereafter, by heating and curing the liquid raw material under pressure in a sealed state, a roller member having a uniform and fine cell structure and less hardness variation can be obtained.
[0030]
Here, the timing at which the cap member 16 is pushed up is immediately after the mold 10 is filled with a predetermined amount of the liquid material corresponding to the volume, and actually the liquid material flows out of the vent hole 17 even a little. The push-up may be started at the time when the operation starts. Accordingly, it is possible to manufacture the roller member with a high yield while eliminating waste of the liquid raw material.
[0031]
Further, as shown in FIG. 3 (b), in this apparatus, when the liquid material injection side opening and the opposite side opening of the mold 10 are respectively closed by the corresponding plug-like members 13a and 13b, The mold side end surface X of the cap member 16 and the mold side end surface Y of the lower plug-shaped member 13b form substantially the same plane. As shown in the figure, this allows the lower end surface of the roller member to be molded to be formed into a flat surface without unevenness, thereby eliminating waste of raw materials and preventing the generation of burrs.
[0032]
In the above description, the procedure for sealing by pushing up the cap member 16 with the mold 10 fixed is shown. However, in the illustrated apparatus, the cap member 16 is fixed and the upper cap 18 is fixed. It is also possible to perform sealing by pushing down the mold 10 together. Also in this case, the flow of the sealing operation is the same as described above.
[0033]
Further, the material of the shaft of the roller member that can be used in the present invention and the composition of the liquid raw material are not particularly limited, and a commonly used material can be appropriately used. For example, a metal shaft is used as the shaft. By using a polyurethane raw material as the liquid raw material, a roller member having a structure in which a polyurethane foam layer is supported on the outer periphery of the shaft can be obtained. As such a polyurethane raw material, for example, the following polyisocyanate component and polyol component can be used.
[0034]
As the polyisocyanate component, aromatic isocyanate, aliphatic isocyanate, alicyclic isocyanate, and derivatives thereof can be used. Among them, aromatic isocyanate and derivatives thereof, particularly tolylene diisocyanate, diphenylmethane diisocyanate, and these Derivatives are preferably used.
[0035]
Examples of tolylene diisocyanate and derivatives thereof include crude tolylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate. These urea-modified products, burette-modified products, carbodiimide-modified products, and the like are used.
[0036]
As diphenylmethane diisocyanate and its derivatives, for example, diphenylmethane diisocyanate and its derivatives obtained by phosgenating diaminodiphenylmethane and its derivatives are used. Examples of the derivatives of diaminodiphenylmethane include polynuclear bodies, and pure diphenylmethane diisocyanate obtained from diaminodiphenylmethane, polymeric diphenylmethane diisocyanate obtained from a polynuclear body of diaminodiphenylmethane, and the like can be used. Regarding the number of functional groups of polymeric diphenylmethane diisocyanate, a mixture of pure diphenylmethane diisocyanate and polymeric diphenylmethane diisocyanate having various functional groups is usually used, and the average number of functional groups is preferably 2.05 to 4.00, more preferably 2. .50 to 3.50 are used. Derivatives obtained by modifying these diphenylmethane diisocyanates and derivatives thereof, such as urethane modified products modified with polyols, dimers formed by uretidione formation, isocyanurate modified products, carbodiimide / uretonimine modified products, allophanate modified products , Urea-modified products, burette-modified products, and the like can also be used. Further, several types of diphenylmethane diisocyanate and derivatives thereof may be blended.
[0037]
As the polyol component, polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide, polytetramethylene ether glycol, polyester polyol obtained by condensing acid component and glycol component, polyester polyol obtained by ring-opening polymerization of caprolactone, polycarbonate diol, etc. are used. be able to.
[0038]
Examples of polyether polyols obtained by addition polymerization of ethylene oxide and propylene oxide include water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane, hexanetriol, triethanolamine, diglycerin, pentaerythritol, ethylenediamine, and methylglucotite. , Aromatic diamine, sorbitol, sucrose, phosphoric acid, etc. as starting materials, and those obtained by addition polymerization of ethylene oxide and propylene oxide. Particularly, water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane. Those starting from hexanetriol are preferred. Regarding the ratio of ethylene oxide and propylene oxide to be added and the microstructure, the ratio of ethylene oxide is preferably 2 to 95% by weight, more preferably 5 to 90% by weight, and ethylene oxide is added to the terminal. preferable. In addition, the arrangement of ethylene oxide and propylene oxide in the molecular chain is preferably random.
[0039]
The molecular weight of the polyether polyol is bifunctional when water, propylene glycol, or ethylene glycol is used as a starting material, and preferably has a weight average molecular weight in the range of 300 to 6000, preferably in the range of 400 to 3000. Is more preferable. Further, when glycerin, trimethylolpropane, and hexanetriol are used as starting materials, they are trifunctional, and those having a weight average molecular weight in the range of 900 to 9000 are preferable, and those in the range of 1500 to 6000 are more preferable. Furthermore, a bifunctional polyol and a trifunctional polyol can be appropriately blended and used.
[0040]
Polytetramethylene ether glycol can be obtained, for example, by cationic polymerization of tetrahydrofuran, and those having a weight average molecular weight in the range of 400 to 4000, particularly in the range of 650 to 3000 are preferably used. It is also preferable to blend polytetramethylene ether glycols having different molecular weights. Furthermore, polytetramethylene ether glycol obtained by copolymerizing an alkylene oxide such as ethylene oxide or propylene oxide can also be used.
[0041]
Further, it is also preferable to use a blend of polytetramethylene ether glycol and a polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide. In this case, it is preferable to use such a blend ratio so that the weight ratio is in the range of 95: 5 to 20:80, particularly 90:10 to 50:50.
[0042]
In addition to the polyol component, a polymer polyol obtained by modifying the polyol with acrylonitrile, a polyol obtained by adding melamine to the polyol, a diol such as butanediol, a polyol such as trimethylolpropane, or a derivative thereof may be used in combination.
[0043]
These polyol component and polyisocyanate component may be used by prepolymerizing polyol with polyisocyanate in advance. As the method, a polyol and a polyisocyanate are put in a suitable container, sufficiently stirred, and kept at 30 to 90 ° C., preferably 40 to 70 ° C. for 6 to 240 hours, preferably 24 to 72 hours. Is mentioned.
[0044]
Catalysts used for the curing reaction of polyurethane raw materials include monoamines such as triethylamine and dimethylcyclohexylamine, diamines such as tetramethylethylenediamine, tetramethylpropanediamine, and tetramethylhexanediamine, pentamethyldiethylenetriamine, pentamethyldipropylenetriamine, tetra Triamines such as methylguanidine, triethylenediamine, dimethylpiperazine, methylethylpiperazine, cyclic amines such as methylmorpholine, dimethylaminoethylmorpholine, dimethylimidazole, dimethylaminoethanol, dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, methylhydroxy Alcohol amines such as ethyl piperazine and hydroxyethyl morpholine; (Dimethylaminoethyl) ether, ether amines such as ethylene glycol (dimethyl) aminopropyl ether, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin marker, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyl And organometallic compounds such as tin marker peptide, dioctyl tin thiocarboxylate, phenylmercury propionate and lead octenoate. These catalysts may be used alone or in combination of two or more.
[0045]
When imparting conductivity to the roller member, a conductive material can be added to a liquid material such as a polyurethane material. Conductive materials include ionic conductive materials and electronic conductive materials, and ionic conductive materials include octadecyltrimethylammonium such as dodecyltrimethylammonium such as tetraethylammonium, tetrabutylammonium and lauryltrimethylammonium, hexadecyltrimethylammonium and stearyltrimethylammonium. , Ammonium perchlorate such as benzyltrimethylammonium and modified aliphatic dimethylethylammonium, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, alkylsulfate, carboxylic acid Organic ionic conductive materials such as salts and sulfonates; perchlorates, chlorates, hydrochlorides, bromates, iodates, and borates of alkali metals or alkaline earth metals such as lithium, sodium, calcium, and magnesium Hydroiodide, trifluoromethyl sulfate, and inorganic ion conductive material such as sulfonate. Further, as the electronic conductive material, conductive carbon black such as ketjen black, acetylene black, etc .; carbon black for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, MT; for ink such as oxidized carbon black Carbon black, pyrolytic carbon black, graphite; conductive metal oxides such as tin oxide, titanium oxide, and zinc oxide; metals such as nickel and copper; carbon whiskers, graphite whiskers, titanium carbide whiskers, conductive potassium titanate whiskers, Examples thereof include conductive whiskers such as conductive barium titanate whiskers, conductive titanium oxide whiskers, and conductive zinc oxide whiskers. By appropriately adding these conductive materials, the volume specific resistance of the roller member can be adjusted.
[0046]
In addition, in liquid raw materials such as polyurethane raw materials, in addition to the above conductive materials, fillers such as inorganic carbonates, foam stabilizers such as silicone foam stabilizers and various surfactants, phenol and phenylamine, depending on applications. An antioxidant such as an anti-friction agent, a friction reducing agent, a charge adjusting agent and the like can be appropriately added. Among these, as the silicone foam stabilizer, a dimethylpolysiloxane / polyoxyalkylene copolymer or the like can be suitably used, and comprises a dimethylpolysiloxane moiety having a molecular weight of 350 to 15000 and a polyoxyalkylene moiety having a molecular weight of 200 to 4000. Those are particularly preferred. The molecular structure of the polyoxyalkylene moiety is preferably an addition polymer of ethylene oxide or a co-addition polymer of ethylene oxide and propylene oxide, and its molecular terminal is preferably ethylene oxide. Examples of the surfactant include cationic surfactants, anionic surfactants, ionic surfactants such as amphoteric, and nonionic surfactants such as various polyethers and various polyesters. The blending amount of the silicone foam stabilizer and various surfactants is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the polyurethane raw material.
[0047]
【Example】
Hereinafter, the present invention will be described specifically by way of examples.
Examples and comparative examples As the cylindrical mold 10 shown in Fig. 1, the inner peripheral surface (surface average roughness Ra: 3.3) of a SUS pipe (inner diameter φ 16.0 mm, outer diameter φ 20.0 mm). 2 μm or less) was prepared by spray coating with a coating layer having a thickness of 5 to 10 μm in which the additive shown in Table 1 was dispersed in the base resin shown in Table 1 below. The mold 10 was assembled in the manufacturing apparatus shown in FIG. 3 and a roller member sample was produced according to the following procedure.
[0048]
<Sample preparation>
(1) A metal shaft 12 having an outer diameter of 6 mm was set in advance in the manufacturing apparatus shown in the figure, and the mold 10 was preheated to 80 ° C.
(2) A foamed polyurethane raw material adjusted to have a roller shape (outer diameter φ16 mm) and a hardness (Asuka-C) of 40 to 50 ° was poured into the mold 10.
(3) Thereafter, the mold 10 was completely sealed so that the foamed polyurethane raw material did not leak and cured at 110 ° C. for 30 minutes. In the sealing operation, when the foamed polyurethane raw material starts to flow out from the vent hole 17 of the manufacturing apparatus, the cap member 16 is pushed up, and the plug-like member 13a above the metal shaft 12 and the plug-like member 13b below are sequentially press-fitted. This was performed by closing the upper opening and the lower opening of the mold 10 by press-fitting into the portions 14a and 14b (see FIGS. 3 and 4).
(4) The sample was taken out after 30 minutes and allowed to stand until the mold temperature dropped to 25 ° C. or lower to obtain a sample for measuring mold release force.
[0049]
<Demolding force measurement>
As shown in FIG. 5, the roller member sample was demolded by placing the mold 10 vertically and pushing the metal shaft 12 in the direction of the arrow. The force applied at this time was measured with a tensile compression tester as follows.
[0050]
FIG. 6 shows a load curve at the time of roller demolding, which represents the relationship between the sample moving distance and the demolding force in the tensile compression tester. The maximum value associated with the increase in the number of demolding when the mold is used repeatedly by repeating the above sample preparation procedure with the maximum demolding force value corresponding to the portion surrounded by the dotted line shown in the figure as the maximum demolding force. The variation of demolding force was evaluated. The values of the initial maximum demolding force are shown in Table 1 below, and the relationship between the demolding frequency and the demolding force is shown in FIG. In addition, in FIG. 7, for the case where the graph is interrupted when the number of demolding is less than 50 times, it indicates that the mold cannot be removed from the mold at that time, and the mold becomes substantially unusable. ing.
[0051]
[Table 1]

[0052]
【The invention's effect】
As described above, according to the present invention, the force required at the time of demolding can be reduced even when used in a method of performing integral molding substantially under pressure. It is possible to realize a roller member manufacturing die that can be manufactured satisfactorily and a method of manufacturing a roller member using the same.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a roller member manufacturing die according to an example of the present invention.
2 is an enlarged partial cross-sectional view showing the vicinity of the inner surface of the roller member manufacturing mold in FIG. 1; FIG.
FIGS. 3A and 3B are schematic cross-sectional views showing a roller member manufacturing apparatus according to the present invention. FIGS.
4A and 4B are cross-sectional views taken along lines AA ′ and BB ′ in FIG. 3, respectively.
FIG. 5 is an explanatory diagram relating to measurement of a demolding force of a roller member in an example.
FIG. 6 is a graph of a load curve at the time of roller demolding showing the relationship between the moving distance of the roller and the demolding force in the tensile compression tester.
FIG. 7 is a graph showing the relationship between the number of demolding and the demolding force in Examples and Comparative Examples.
[Explanation of symbols]
1 Base resin (FEP resin)
2 Resin particles 3 Coating layer 10 Mold 11 Inner peripheral surface 12 Shafts 13a, 13b Plug-like members 14a, 14b Press-fit portion 15a Upper end portion 15b Lower end portion 16 Cap member 17 Vent hole 18 Upper cap 20 Injection nozzle

Claims (7)

In the mold for roller member production, which has a cylindrical shape and is used in a molding process in which a foam layer is integrally formed on the outer periphery of a shaft by foaming and curing a liquid raw material.
A coating layer in which resin particles containing a fluororesin are dispersed in a tetrafluoroethylene-hexafluoropropylene copolymer as a base resin is formed on at least a region of the inner peripheral surface that is in contact with the foam layer, A roller member manufacturing mold, wherein the particle diameter of the resin particles is larger than the maximum film thickness of the base resin in the coating layer. 2. The roller member manufacturing die according to claim 1, wherein the resin particles are made of PTFE (polytetrafluoroethylene). The roller member manufacturing die according to claim 1 or 2, wherein a particle diameter of the resin particles is three times or less of a maximum film thickness of the base resin. The roller member manufacturing die according to any one of claims 1 to 3, wherein the base resin has a thickness of 5 to 10 µm. A foam material layer is formed on the outer periphery of the shaft by injecting a liquid raw material previously foamed into the mold with the shaft penetrating the center line of the cylindrical mold, and heating and curing. In the manufacturing method of the roller member including the formation process to form, The manufacturing method of the roller member characterized by using the metallic mold for roller member manufacture as described in any one of Claims 1-4 as said metallic mold. 6. The liquid raw material is heat-cured in a state where both ends of the mold are closed and the mold is sealed immediately after a predetermined amount of the liquid raw material is injected into the mold. Manufacturing method. The production method according to claim 5 or 6, wherein a polyurethane raw material is used as the liquid raw material.

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