JP3983525B2 - Urethane roller casting method - Google Patents

Description

【００２５】
【表２】

【００２６】
尚、第２表中の「結果」は、作成したローラの表面から見える部分に存在する、空気巻き込みに起因する径１ｍｍ以上の孔の数により、次の基準で評価した結果である。
○：０個 △：１〜３個 ×：４個以上
【００２７】
【発明の効果】
以上説明してきたように、本発明によれば、高圧発泡法における空気の巻き込みの問題点を解消して、表面性の悪化や密度の不均一、ローラ性能のバラツキ等の問題がなく、各種ローラ部材として好適に用いることのできるウレタンローラを、産業廃棄物を発生させず製造することができるウレタンローラの注型方法および注型装置を得ることができる。
【図面の簡単な説明】
【図１】注型装置の構成の一例を示す説明図である。
【図２】従来の吐出ヘッドの一例及びその作動順序を示す説明図である。
【図３】本発明の吐出ヘッドの一例及びその作動順序を示す説明図である。
【符号の説明】
１ 吐出ヘッド
２ ポリオール成分系の貯蔵タンク
３ イソシアネート成分系の貯蔵タンク
４ａ、４ｂ 油圧ピストン
５ａ、５ｂ オイルバイパス
６ａ、６ｂ 分岐部
７ａ、７ｂ 循環流路
８ａ、８ｂ 吐出流路
１１ クリ−ニングロッド
１２ 吐出口
１３ プランジャー
１４ａ、１４ｂ 流入口
１５ 空間
１６ 開閉蓋[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for casting a urethane roller (hereinafter, also simply referred to as “roller”), and in particular, there are no problems such as deterioration of surface properties, non-uniform density, and variations in roller performance, and is suitable as various roller members. TECHNICAL FIELD The present invention relates to a urethane roller casting method and a casting apparatus capable of producing a urethane roller that can be used for manufacturing without generating industrial waste.
[0002]
[Prior art]
In an electrophotographic apparatus such as a copying machine, a printer, a facsimile, or an electrostatic recording apparatus, a toner supply roller and a developing roller are used in each process such as charging, toner layer formation, development, cleaning, paper feeding, and conveyance in an electrophotographic process. Rollers made of an elastic material or a resin material such as a transfer roller, a paper feed roller, and a transport roller play various roles.
[0003]
In many of these various roller members, a urethane roller in which a urethane foam layer mainly composed of a urethane material is formed on the outer periphery of a roller shaft is used. In the urethane roller as such various roller members, it is required that the urethane foam layer has no deterioration in surface properties, non-uniform density, variation in roller performance, and the like.
[0004]
On the other hand, as a manufacturing method of the urethane roller used as these various roller members, a urethane foam body is supported on the surface of the roller shaft, and the outer surface of the urethane foam body is processed to form a cylindrical roller shape. A method of foam-molding a foam layer integrally with a metal shaft in a molding die has been proposed.
[0005]
However, in the former method, the surface property is deteriorated because fuzz or the like due to post-processing such as polishing remains on the roller surface, which may cause defects or defects when mounted on an actual machine. There is a problem that the production efficiency is lowered due to the complexity. Even in the latter method, there are problems such as non-uniform density in the urethane foam layer formed for foaming in the mold and defects due to unfilled portions and air entrainment. In either case, a high-performance urethane roller could not be produced with a good yield.
[0006]
In contrast to these methods, as a method for producing a urethane roller that does not have the above-mentioned problems, a technique for obtaining a polyurethane foam molded article having a fine cell structure by press-fitting foam into a mold has been proposed. This uses a technique (mechanical floss) for forming a foam by mechanical stirring, compared to the technique using a general low-pressure foaming method using water as a foaming agent.
[0007]
However, according to the above technique, a urethane roller having excellent surface properties and roller performance can be obtained, but the first and last portions of the foam produced by stirring do not become completely uniform. Therefore, it has to be discarded because it causes a problem in performance. That is, as in the case of the low pressure foaming method, the generation of industrial waste could not be avoided. In addition, none of these techniques is suitable for continuous roller production.
[0008]
[Problems to be solved by the invention]
As a method of solving the above-mentioned problems in the prior art, when injecting a urethane material composed of a polyol component system and an isocyanate component system into a molding die, both component systems collide with each other under high pressure in the discharge head of the injection device. A method of mixing and high-pressure foaming (hereinafter sometimes referred to as “high-pressure foaming method”) is known. In this method, since a uniform foamed state is obtained, there are no problems such as deterioration in surface property, non-uniformity in density, and variations in roller performance, and it is possible to produce urethane rollers that can be suitably used as various roller members. It is a method.
An example of a casting apparatus that can be used for casting a roller by high pressure foaming is shown in FIG. The illustrated casting apparatus includes a polyol component-based storage tank 2, an isocyanate component-based storage tank 3, a discharge head 1, and a pair of hydraulic pistons 4a, 4b for independently circulating both component systems. I have. Both component systems circulated at a high pressure by the pair of hydraulic pistons 4a and 4b flow from the circulation passages 7a and 7b connecting the storage tanks 2 and 3 and the hydraulic pistons 4a and 4b via the branch portions 6a and 6b. It flows to the paths 8a and 8b and flows into the discharge head 1. High-pressure foaming can be performed by injecting both component systems whose pressures are adjusted to a predetermined high-pressure range into the discharge head 1 from opposite directions and performing impact mixing.
[0009]
Such a discharge head 1 includes a straight type head and an L type head. FIG. 2 is a schematic diagram showing an example of the L type head in the state of the discharge head 1.
(A) shows a state in which the hydraulic cleaning rod 11 moves while cleaning the inside of the discharge head 1 and the tip thereof reaches the position of the discharge port 12. In this state, the hydraulic plunger 13 is moved to a position where the inlets 14 a and 14 b of both component systems are closed, and no space exists in the discharge head 1.
(B) shows a state in which the cleaning rod 11 has retreated from the state of (a) and a space 15 is formed in the discharge head 1.
(C) shows a state in which the plunger 13 is further retracted from the state of (b) to form a larger space 15 in the discharge head 1 and the inlets 14a and 14b of both component systems are opened. .
From the state of (a) to the state of (c) through the state of (b), both pressurized components are injected from the inflow ports 14a and 14b in opposite directions, and are mixed by collision. .
However, at this time, as shown in (d), which is an enlarged view of the portion surrounded by a circle in (c), the air existing in the space 15 in the ejection head 1 is separated from both components as if the third component. Although mixed, this air entrainment generates voids in the urethane foam layer, which lowers the performance of the roller.
Since air entrainment occurs at the initial flow stage when it is discharged from the injection device and injected into the molding die, as a countermeasure, a trap is provided in the injection molding die to remove the initial flow portion. -Although the disposal method is adopted, when the injection amount is very small, the proportion of the used raw material to be discarded becomes large, resulting in a huge amount of industrial waste.
Conventionally, there is a method of casting the mold in a vacuum state, which has been considered as a countermeasure against air entrainment, but the mold structure is complicated and additional equipment such as a vacuum pump is required. There are disadvantages such as.
[0010]
Therefore, the object of the present invention is to eliminate the problem of air entrainment in the above-described high pressure foaming method, and there are no problems such as deterioration of surface properties, non-uniformity of density, variation in roller performance, etc., and it is suitable as various roller members. An object of the present invention is to provide a urethane roller casting method and a casting apparatus capable of producing a urethane roller that can be used without generating industrial waste.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is as follows.
(1) When a urethane material composed of a polyol component system and an isocyanate component system is injected into a molding die to form a urethane foam layer, both component systems are used as a cleaning rod and a plunger in a discharge head of a casting apparatus. In a casting method of urethane material, which is made to collide and mix under high pressure in a space generated by retreating and discharged from the discharge port of the discharge head in a high-pressure foamed state and injected into a molding die, the discharge port Provided with an opening / closing lid, and closing the opening / closing lid to prevent entry of air into the discharge head, except when the urethane material is injected into the molding die, and the opening / closing lid is connected to the cleaning rod. plunger moves forward to close at the time when the space in the ejection head no longer exists, then is retracted a cleaning rod and the plunger is closed the lid , And thereby caused to collide at high pressure the two-component system in the space in a vacuum state generated in the discharge head, whereby the volume ratio satisfying the space created within the discharge head of the high pressure foamed urethane material is 80% or more Urethane material casting method, characterized by opening when
[0012]
( 2 ) The casting method according to (1 ), wherein the collision mixing of the two component systems is performed at a pressure of 5 to 30 MPa.
( 3 ) A method for casting a urethane roller comprising a cored bar and a urethane foam layer provided integrally on the outer periphery of the cored bar, the cored bar being penetrated on the center line of the molding die The casting method according to (1) or (2) , wherein the injection is performed in a state where
( 4 ) The casting method according to any one of (1) to ( 3 ), wherein the injection is performed at a supply amount of the urethane material of 1 to 50 g / sec, and ( 5 ) a polyol component system A storage tank; an isocyanate component-based storage tank; an opposing two-component inlet, a cleaning rod, a plunger, and a discharge head having a high-pressure foamed urethane material discharge port; and the two storage tanks in the casting apparatus having a pair of oil Zhuang piston to flow into the head out ejection by circulating independently both component from in conjunction with a timer to the discharge port, the discharge and forward cleaning rod and plunger When there is no more space in the head, it closes, and the cleaning rod and plunger move backward to create a high-pressure foamed urethane material in the space created in the discharge head. Casting apparatus urethane rollers, characterized in that the volume ratio that satisfies the space created in the output head is provided with a lid that opens and closes to open when it becomes 80% or more.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 3 is a schematic diagram showing the state of the ejection head of the casting apparatus used in the method of the present invention. The ejection port 12 is provided with an opening / closing lid 16.
2A shows a state in which the hydraulic cleaning rod 11 has moved to the position of the discharge port 12 while cleaning the inside of the discharge head 1, as in FIG. The open / close lid 16 is opened when the cleaning rod 11 is moving, but the tip of the cleaning rod 11 reaches the position of the discharge port 12 to finish cleaning, and the space in the discharge head 1 is reached. Is no longer present and is in the state of (a).
[0014]
FIG. 2B shows a state in which the cleaning rod 11 is retracted and a space 15 is formed in the discharge head 1 as in FIG. 2B, but the open / close lid 16 remains closed. The space 15 in 1 is in a vacuum state without air.
FIG. 2C shows a state in which the plunger 13 is further moved backward to form a larger space 15 in the discharge head 1 and the inlets 14a and 14b of both component systems are opened, as in FIG. Show.
In the state of (c), both pressurized components are injected from the inflow ports 14a and 14b in opposite directions and collide and mix, but at the time of starting injection, the open / close lid 16 remains closed, Air does not exist in the space 15, and therefore air entrainment as shown in FIG. 2D does not occur.
After both components have collided and high pressure foaming has started, the open / close lid 16 is opened to bring the foamed urethane material into the molding die to be ejected from the ejection port 12 to the state (d). Although it is necessary, if it opens too early, air may enter from the discharge port 12 and air may be entrained. Therefore, the space generated in the discharge head 1 by the backward movement of the cleaning rod 11 and the plunger 13. In other words, when the volume ratio (hereinafter referred to as filling rate) filled with the high pressure foamed urethane material fills the space existing in the discharge head 1 at the time when high pressure foaming starts is 80% or more. It is preferable to open the opening / closing lid 16.
[0015]
The surface of the opening / closing lid 16 that is in contact with the discharge port 12 is preferably made of an elastic material such as rubber because sealing properties are required. However, if the frictional force against the protruding port is too strong, a force is required for opening and closing. Since there may be a timing shift, it is preferable to select one having an appropriate characteristic according to the opening / closing method and mechanism.
In FIG. 3, the opening / closing lid 16 is drawn as a separate object from the molding die, but the present invention aims to prevent air from entering the space inside the ejection head 1. Equivalent effects can be obtained by providing an opening / closing mechanism to the molding die in close contact with each other. The present invention includes such an embodiment.
[0016]
The high-pressure foaming in the present invention means that a polyol component system and an isocyanate component system as a urethane material are impact-mixed and foamed under high pressure, preferably at a pressure of 5 to 30 MPa, particularly 10 to 20 MPa.
In this case, the reason that the pressure pressure is 5 to 30 MPa is that if the pressure is higher than this, the supply amount of the discharge liquid from the discharge head 1 is too large, which is not suitable for casting of the urethane roller. is there. The preferable supply amount of the urethane material in the casting method of the present invention is 1 to 50 g / sec, particularly 3 to 40 g / sec.
[0017]
There is no restriction | limiting in particular as a polyol component which can be used as a urethane material, For example, polyether polyol, polytetramethylene ether glycol, THF-alkylene oxide copolymer polyol, polyester polyol, acrylic polyol, polyolefin polyol, ethylene-acetic acid A partially saponified product of a vinyl copolymer, a phosphate polyol, a halogen-containing polyol, or the like can be suitably used.
[0018]
The isocyanate component is not particularly limited, and not only general-purpose TDI, MDI, crude-MDI (polymeric MDI), and modified MDI, but also a special isocyanate may be used. Special isocyanates include, for example, 1,5-naphthalene diisocyanate, tolidine diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, transcyclohexane-1,4-diisocyanate, xylylene diisocyanate (XDI), hydrogenated- XDI, hydrogenated-MDI, lysine diisocyanate, triphenylmethane triisocyanate, tris (isocyanatephenyl) thiophosphate, tetramethylxylene diisocyanate, lysine ester triisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate- 4-isocyanatomethyloctane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate Anate, trimethylhexamethylene diisocyanate and the like can be mentioned, and these can also be suitably used.
[0019]
As a urethane material, in addition to these polyurethane raw materials, a crosslinking agent, a foaming agent (water, low-boiling substances, etc.), a surfactant, a catalyst, and the like can be added, and thereby characteristics as desired can be obtained. . In addition, flame retardants and fillers, conductive agents such as ionic conductive agents and electronic conductive agents, and known fillers and cross-linking agents can be used as appropriate. Examples of ionic conductive agents include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (eg, lauryltrimethylammonium), hexadecyltrimethylammonium, octadecyltrimethylammonium (eg, stearyltrimethylammonium), benzyltrimethylammonium, modified fatty acid dimethylethyl Perchlorates such as ammonium, chlorates, hydrochlorides, bromates, iodates, borofluorides, sulfates, ethyl sulfates, carboxylates, ammonium salts such as sulfonates, lithium, Perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, trifluoromethyl of alkali metals and alkaline earth metals such as sodium, potassium, calcium and magnesium Examples thereof include sulfates and sulfonates.
[0020]
Examples of the electronic conductive agent include conductive carbon such as ketjen black and acetylene black; carbon for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT; for ink subjected to oxidation treatment Examples thereof include carbon, pyrolytic carbon, natural graphite, and artificial graphite; conductive metal oxides such as tin oxide, titanium oxide, and zinc oxide; metals such as nickel, copper, silver, and germanium.
[0021]
【Example】
Hereinafter, the present invention will be described based on examples.
Examples 1-4
As shown in FIG. 1, it is provided between the hydraulic circuit of the violol component-based storage tank 2, the isocyanate component-based storage tank 3, the discharge head 1, the pair of hydraulic pistons 4a and 4b, and the hydraulic pistons 4a and 4b. By using a casting apparatus equipped with oil bypasses 5a and 5b, both components are ejected and collided at an ejection pressure of 15 MPa in the discharge head 1, and a urethane material is high-pressure foamed and injected into a molding die, The urethane roller was cast.
As the discharge head 1, the one provided with the opening / closing lid 16 shown in FIG. 3 is used. By setting the timer, the plunger 13 is retracted, the inflow ports 14 a and 14 b are opened, and ejection and collision of both components are started. When the high-pressure foamed urethane material satisfies a certain percentage of the volume of the discharge head space, the opening / closing lid 16 is opened. On the side of the opening / closing lid 16 in contact with the discharge port, a rubber and PTFE (polytetrafluoroethylene) film layer was provided with the PTFE film layer as the surface.
The contents of the polyol component and isocyanate component of the urethane material are as shown in Table 1.
[0022]
The results of changing the filling rate of the opening / closing lid 16 to 100 to 70% were as shown in Table 2.
The urethane rollers obtained in Examples 1 to 3 had no air entrainment and could be suitably used as a roller member. Further, the urethane roller obtained in Example 4 had some holes due to air entrainment, but was not so large that it could not be used as a roller member.
[0023]
Comparative Example 1
As the ejection head 1, the same operation as in Example 1 was carried out except that the one shown in FIG.
The results are as shown in Table 2. It was recognized that the surface of the roller had many holes due to the entrainment of air and was inferior in performance as a roller member.
[0024]
[Table 1]

[0025]
[Table 2]

[0026]
The “result” in Table 2 is a result of evaluation based on the following criteria based on the number of holes having a diameter of 1 mm or more due to air entrainment existing in the portion visible from the surface of the created roller.
○: 0 △: 1 to 3 ×: 4 or more [0027]
【The invention's effect】
As described above, according to the present invention, the problem of air entrainment in the high pressure foaming method is solved, and there are no problems such as deterioration of surface properties, non-uniform density, variation in roller performance, and the like. It is possible to obtain a urethane roller casting method and a casting apparatus capable of producing a urethane roller that can be suitably used as a member without generating industrial waste.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an example of a configuration of a casting apparatus.
FIG. 2 is an explanatory diagram showing an example of a conventional discharge head and its operation sequence.
FIG. 3 is an explanatory diagram showing an example of an ejection head according to the present invention and its operation sequence.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Discharge head 2 Polyol component-type storage tank 3 Isocyanate component-type storage tank 4a, 4b Hydraulic piston 5a, 5b Oil bypass 6a, 6b Branch part 7a, 7b Circulation flow path 8a, 8b Discharge flow path 11 Cleaning rod 12 Discharge port 13 Plungers 14a and 14b Inlet 15 Space 16 Open / close lid

Claims (4)

When a urethane foam layer is formed by injecting a urethane material consisting of a polyol component system and an isocyanate component system into a molding die, the cleaning rod and plunger in the ejection head of the casting apparatus are retracted. In a casting method of urethane material that is collided and mixed under high pressure in a space generated by discharging and discharged from the discharge port of the discharge head in a high-pressure foamed state and injected into a molding die, an opening / closing lid is provided at the discharge port Except when injecting urethane material into the mold, the opening / closing lid is closed to prevent air from entering the discharge head, and the opening / closing lid is connected to the cleaning rod and plunger. Close when the space is no longer present in the discharge head and then move the cleaning rod and plunger backward with the open / close lid closed. The two component systems collided under high pressure in a vacuum space generated in the discharge head by the above, whereby the volume ratio satisfying the space generated in the discharge head of the urethane material foamed with high pressure became 80% or more. A casting method of urethane material characterized by opening at the time.  The casting method according to claim 1, wherein the collision mixing of the two component systems is performed at a pressure of 5 to 30 MPa.  A casting method of a urethane roller comprising a cored bar and a urethane foam layer provided by integral molding on the outer periphery of the cored bar, wherein the cored bar is provided in a state of being penetrated on the center line of the molding die 3. The casting method according to claim 1, wherein the injection is performed.  The casting method according to any one of claims 1 to 3, wherein the injection is performed at a supply amount of the urethane material of 1 to 50 g / sec.

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