JP2002307454A - Method and apparatus for cast molding of urethane roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus for the cast molding of a urethane roller capable of continuously manufacturing the urethane roller not having problems such as the deterioration of surface properties, the non-uniformity of density, the irregularity of roller capacity or the like and suitably usable as various roller members in a good yield without generating industrial waste and excellent in cost properties and productivity. SOLUTION: In the method for the cast molding of the urethane roller, forming a urethane foam layer by injecting a urethane material consisting of a polyol component system and an isocyanate component system in a cylindrical mold, both component systems are allowed to collide with each other to be mixed under high pressure at the time of injection of the urethane material to be foamed under high pressure. The cast molding apparatus is equipped with a storage tank 2 of the polyol component system, a storage tank 3 of the isocyanate component system, a discharge head 1 and a pair of hydraulic pistons 4a and 4b for independently circulating both component systems from two storage tanks 2 and 3 to allow them to flow in the discharge head 1 and the discharge head 1 has the opposed inflow ports 9 and 10 of both component systems. The hydraulic pistons 4a and 4b have oil bypasses 5a and 5b between hydraulic circuits.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a urethane roller (hereinafter, also simply referred to as "roller"). More specifically, there is no local variation in roller performance such as resistance and hardness.
The present invention relates to a casting method and a casting apparatus for a urethane roller capable of efficiently and inexpensively manufacturing a urethane roller that can be suitably used as various rollers in an electrophotographic apparatus or an electrostatic recording apparatus.

[0002]

2. Description of the Related Art In an electrophotographic apparatus such as a copying machine, a printer, and a facsimile, and an electrostatic recording apparatus, toner is supplied in each step of charging, forming a toner layer, developing, cleaning, feeding, and transporting in an electrophotographic process. Rollers made of an elastic material or a resin material, such as a roller, a developing roller, a transfer roller, a paper feed roller, and a transport roller, play various roles.

[0003] 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 often used in these various roller members. In such a urethane roller as various roller members, it is required that the urethane foam layer has a uniform internal and surface structure, and that there is no local variation in roller performance such as resistance and hardness.

On the other hand, as a method of manufacturing urethane rollers used as these various roller members, there is a method in which a urethane foam body is carried on the surface of a roller shaft, and the outer surface of the urethane foam body is processed into a cylindrical roller shape. Also, a method has been proposed in which a urethane foam layer is foam-molded in a cylindrical mold integrally with a metal shaft (JP-A-9-274373, JP-A-5-188774, etc.).

However, in the former method,
Fluffiness due to post-processing such as polishing remains on the roller surface, which deteriorates the surface properties and causes defects or defects when mounted on the actual machine, or reduces the production efficiency because the manufacturing process becomes complicated. There were problems such as getting lost. Also, in the latter method, unevenness in density occurs in the urethane foam layer formed for foaming in the mold,
There are problems such as occurrence of defects due to unfilled portions and entrainment of air, and in any case, high performance urethane rollers cannot be manufactured with good yield.

[0006] In contrast to these methods, there has been proposed a technique for producing a polyurethane foam molded article having a fine cell structure by press-fitting a foam into a mold as a method for producing a urethane roller which does not have the above-mentioned problems (Patent). No. 29906
No. 16). This uses a technique (mechanical floss) for forming a foam by mechanical stirring, in contrast to the technique using the above-mentioned general low-pressure foaming method using water as a foaming agent.

[0007]

However, according to the above technique, although a urethane roller having excellent surface properties and roller performance can be obtained, the first and last portions of the foam produced by stirring are completely removed. Because it does not become a uniform foam state and therefore causes problems in performance,
I had to discard it. That is, as in the case of the low-pressure foaming method, generation of industrial waste could not be avoided. In addition, none of these techniques are suitable for continuous roller production.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art and eliminate the problems such as deterioration of surface properties, uneven density, and uneven roller performance, and to be suitably used as various roller members. A method and apparatus for urethane roller casting with excellent cost efficiency and productivity, capable of producing urethane rollers continuously and with good yield without producing industrial waste. Is to do.

[0009]

Means for Solving the Problems To solve the above problems, the present invention is as follows. (1) In a casting method of a urethane roller for forming a urethane foam layer by injecting a urethane material composed of a polyol component system and an isocyanate component system into a cylindrical mold, the two component systems collide under high pressure during the injection. This is a method for casting a urethane roller, which comprises mixing and foaming under high pressure.

(2) In the casting method of the above (1), the casting method of a urethane roller comprising a cored bar and a urethane foam layer provided on the outer periphery of the cored bar by integral molding. This is a casting method in which the above-described injection is performed in a state where the core metal is penetrated on the center line of the mold.

(3) In the casting method of the above (1) or (2), the injection is carried out at a supply amount of the urethane material of 1 to 3.
This is a casting method performed at 50 g / sec.

(4) In the casting method according to any one of the above (1) to (3), the impingement mixing of the two component systems is performed at a pressure of 50%.
A casting method carried out in ~300kg / cm ^2.

(5) a storage tank of a polyol component system,
An isocyanate component-based storage tank, a discharge head,
A urethane roller having a pair of hydraulic pistons for independently circulating the two component systems from the two storage tanks and flowing into the discharge head, and having an inflow port of the two component systems facing the discharge head. The casting apparatus for a urethane roller, wherein the hydraulic piston has an oil bypass between hydraulic circuits.

(6) In the casting apparatus of the above (5), the hydraulic piston is provided on the side of the isocyanate component system.
This casting device is smaller than the polyol component side.

(7) In the casting apparatus of (5) or (6), the orifice installed at the inlet of the discharge head has a smaller diameter on the isocyanate component side than on the polyol component side. It is a casting device.

[0016]

Embodiments of the present invention will be specifically described below with reference to the drawings. In the casting method of the urethane roller of the present invention, when forming a urethane foam layer of the roller by injecting a urethane material composed of a polyol component system and an isocyanate component system into a cylindrical mold, at the time of the injection, both component systems Impingement mixing is performed under high pressure to foam at high pressure. By forming the urethane foam layer of the roller using such high-pressure foaming, it is possible to obtain a high-quality urethane roller without defects such as uneven density and roller performance, and with conventional low-pressure foaming and mechanical floss techniques. The inevitable generation of waste materials can be prevented, and excellent cost performance and productivity can be realized.

In the present invention, any condition may be used as long as the urethane foam layer of the roller is formed by the high-pressure foaming described above, and other conditions can be appropriately determined. Here, high-pressure foaming in the present invention means that a polyol component system and an isocyanate component system as urethane materials are mixed under a high pressure, preferably at a pressure of 50 to 300 kg / cm ² , particularly 1
This means that the mixture is subjected to collision mixing at 00 to 200 kg / cm ² and foamed.

FIG. 1 shows a casting apparatus which can be used for casting a roller by high-pressure foaming. 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 and 4b for independently circulating the two component systems. Have. The two component systems circulated at a high pressure by the pair of hydraulic pistons 4a, 4b are discharged from the circulation channels 7a, 7b connecting the storage tanks 2, 3 and the hydraulic pistons 4a, 4b via the branch portions 6a, 6b. It flows to the flow paths 8 a and 8 b and flows into the ejection head 1.

FIG. 2 shows an example of such a discharge head 1.
(A) and (b) can be mentioned.
Indicates a so-called straight type head, and (b) indicates an L-type head. As shown in the figure, the discharge head 1 has an inlet 9 for a polyol component and an isocyanate component,
10 are provided at positions facing each other, and by adjusting the pressure at which the two component systems flow from the inlets 9 and 10 into the above-mentioned predetermined high pressure range, the two component systems are injected from the opposite direction. Then, high-pressure foaming according to the present invention can be performed by collision mixing.

In this case, the pressure is 50 to 300 kg / cm ^2.
The reason 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 urethane roller casting. The preferable supply amount of the urethane material in the casting method of the present invention is 1 to 50 g / s.
ec, especially 3 to 10 g / sec. In the case of a conventional high-pressure foaming machine, the lower limit is 200 g / sec in the supply amount and 100 kg / cm ^{2 in the} pressure, and it cannot be used for casting a roller. . In the apparatus of the present invention, as shown in FIG. 1, since the hydraulic pistons 4a and 4b have the oil bypasses 5a and 5b between the hydraulic circuits, the amount of oil supplied to the hydraulic pistons 4a and 4b As a result, the cylinder speed is reduced, and as a result, the flow rate in the apparatus and, accordingly, the supply amount from the discharge nozzle can be reduced. By reducing the supply amount, an apparatus that can be suitably used in the method of the present invention has been realized.

In this case, in order to circulate each component system stably even at a small flow rate, the hydraulic piston 4b on the isocyanate component system side having a low mixing ratio may be made smaller than the hydraulic piston 4a on the polyol component system side. preferable. Thereby, a small amount can be supplied stably.

In order to stabilize the flow rate at the time of discharge, an orifice (not shown) installed at the inflow port 10 of the discharge head 1 on the isocyanate component side has a smaller diameter than the polyol component side. It is preferable to use one having a diameter suitable for ejection. It is possible to reduce the flow rate with a needle while maintaining the same large orifice as the polyol component system side, but this requires very fine adjustment and the foreign matter in the material clogs the gap and the flow rate cannot be adjusted. It is preferable to use a small-diameter orifice because of problems such as stability. In this case, the circulation channel 7b and the discharge channel 8 on the corresponding isocyanate component system side are further provided.
It is preferable to provide a fine strainer suitable for the small-diameter orifice at the branching portion 6b with b.

The polyol component that can be used as the urethane material is not particularly limited. Examples thereof include polyether polyol, polytetramethylene ether glycol, THF-alkylene oxide copolymer polyol, polyester polyol, acrylic polyol,
Polyolefin polyols, partially saponified ethylene-vinyl acetate copolymers, phosphate-based polyols, halogen-containing polyols, and the like can be suitably used.

The isocyanate component is not particularly limited, and is generally used for TDI, MDI, crude MDI.
(Polymeric MDI) and modified MDI as well as special isocyanates may be used. Specific 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) thiophene phosphate, tetramethylxylene diisocyanate, lysine ester triisocyanate, 1,6,11
-Undecane triisocyanate, 1,8-diisocyanate-4-isocyanatomethyloctane, 1,3
Examples thereof include 6-hexamethylene triisocyanate, bicycloheptane triisocyanate, and trimethylhexamethylene diisocyanate, and these can also be suitably used.

As the urethane material, in addition to these polyurethane raw materials, a crosslinking agent, a foaming agent (water, a low-boiling substance, etc.), a surfactant, a catalyst, and the like can be added, whereby the desired properties can be obtained. be able to. In addition, it is also possible to appropriately use a conductive agent such as a flame retardant or a filler, an ionic conductive agent or an electronic conductive agent, or a known filler or a cross-linking agent. Examples of the ionic conductive agent include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (eg, lauryltrimethylammonium), hexadecyltrimethylammonium, octadecyltrimethylammonium (eg, stearyltrimethylammonium), benzyltrimethylammonium, and a modified fatty acid dimethylethyl. Perchlorates such as ammonium,
Ammonium salts such as chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, ethyl sulfate, carboxylate, sulfonate, lithium, sodium, potassium, calcium, magnesium, etc. Perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, trifluoromethyl sulfate, sulfonate and the like of alkali metals and alkaline earth metals.

Examples of the electron conductive agent include conductive carbon such as Ketjen black and acetylene black;
SAF, ISAF, HAF, FEF, GPF, SRF,
Carbon for rubber such as FT and MT; carbon for oxidation-treated ink, pyrolytic carbon, natural graphite, artificial graphite; conductive metal oxides such as tin oxide, titanium oxide and zinc oxide; nickel, copper, silver, Examples thereof include metals such as germanium.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. EXAMPLE As shown in FIG. 1, a polyol component-based storage tank 2, an isocyanate component-based storage tank 3, a discharge head 1,
A pair of hydraulic pistons 4a, 4b and a hydraulic piston 4a,
Oil bypasses 5a, 5b provided between the hydraulic circuits of 4b
The urethane roller was cast by bubbling the urethane material under high pressure in the discharge head 1 and injecting it into the cylindrical mold using the casting apparatus provided with b. The ejection head 1 was of a straight type shown in FIG. 2A, and the ejection pressure in the ejection head 1 was 100 kg / cm ² and the supply amount from the ejection head 1 was 10 g / sec. As the cylindrical type, an inner diameter of 2 mm with a 6.0 mm diameter core
A cylindrical shape having a length of 0.0 mm and a length of 300 mm was used. The blending contents of the polyol component system and the isocyanate component system of the urethane material are as shown in Table 1 below.

[0028]

[Table 1]

The obtained urethane roller was uniform in density and roller performance, was of good quality without defects, and could be suitably used as various roller members. In addition, the first and last portions of the discharged urethane material can be used for casting a roller, and the obtained roller has no problem in quality and performance.

[0030]

As described above, according to the present invention, a urethane roller which can be suitably used as various roller members without problems such as deterioration of surface properties, non-uniform density, and variation in roller performance. Can be manufactured continuously and with good yield without generating industrial waste, and a casting method and a casting apparatus for a urethane roller excellent in cost and productivity can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a casting device of the present invention.

FIG. 2 is an explanatory diagram illustrating an example of an ejection head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge head 2 Storage tank of polyol component system 3 Storage tank of isocyanate component system 4a, 4b Hydraulic piston 5a, 5b Oil bypass 6a, 6b Branch part 7a, 7b Circulation channel 8a, 8b Discharge channel 9, 10 Inlet

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G03G 15/08 501 G03G 15/08 501A 501D 504 504D 15/16 103 15/16 103 21/10 B29K 75:00 // B29K 75:00 105: 04 105: 04 B29L 31:32 B29L 31:32 G03G 21/00 312 F term (reference) 2H077 AC04 AD06 AD14 AD23 FA22 FA25 2H134 GA01 HA17 HA18 KD08 KD12 KE02 KE04 KG03 KG04 KH10 2H200 FA13 HB12B HB45 JA02 JA25 JB10 LC03 MA03 MA08 MA11 MA12 MA13 MA20 3J103 AA02 AA13 AA32 BA41 CA02 EA02 EA13 GA03 GA57 GA58 GA60 HA03 HA12 HA48 4F204 AA42 AD18 AG20 AH04 AH33 EA01 EB01 EB12 EE16 EF27 EF47

Claims (7)

[Claims] 1. A casting method for a urethane roller for forming a urethane foam layer by injecting a urethane material comprising a polyol component system and an isocyanate component system into a cylindrical mold, wherein the two component systems are subjected to high pressure during the injection. A method of casting a urethane roller, wherein the mixture is subjected to collision mixing and foaming under high pressure. 2. 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, wherein the cored bar extends through a center line of the cylindrical mold. The casting method according to claim 1, wherein the injection is performed in a state where the injection is performed. 3. The casting method according to claim 1, wherein the injection is performed at a supply amount of the urethane material of 1 to 50 g / sec. 4. The method of claim 1, wherein the impingement mixing of the two components is carried out at a pressure of 50 to 50.
The casting method according to claim 1, wherein the casting is performed at 300 kg / cm ² . 5. A storage tank based on a polyol component, a storage tank based on an isocyanate component, a discharge head, and a pair of hydraulic pressures which independently circulate the two component systems from the two storage tanks and flow into the discharge head. A casting apparatus for a urethane roller, comprising a piston, and an inflow port of both components facing the discharge head, wherein the hydraulic piston has an oil bypass between hydraulic circuits. Casting equipment. 6. The casting apparatus according to claim 5, wherein the hydraulic piston is smaller on the isocyanate component side than on the polyol component side. 7. The orifice installed at the inflow port of the discharge head has a smaller diameter on the isocyanate component side than on the polyol component side.
The casting device as described.