Urethane prepolymer and roller for oa

Abstract

To provide a roller for OA that includes a base material layer containing a pigment absorbing ultraviolet light, and an elastomer layer containing an ultraviolet curable elastomer, which suppresses adhesive failures of the elastomer layer without increasing a manufacture time.SOLUTION: An urethane prepolymer is obtained by sealing an NCO group of an NCO group-terminated urethane prepolymer with ultraviolet curable monool and non-ultraviolet curable monool. A roller for OA is obtained by forming a base material layer, a primer layer and an elastomer layer on the outer peripheral surface of a shaft. The base material layer contains a foam resin, and a pigment absorbing ultraviolet light. The primer layer contains a first ultraviolet semi-curable elastomer, and the elastomer layer contains a second ultraviolet curable elastomer. The first ultraviolet curable elastomer contains an elastomer obtained by photopolymerization of a raw material containing the urethane prepolymer.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a urethane prepolymer and an OA roller, and more particularly to an OA roller used in various OA devices such as copiers, facsimiles, laser printers, etc., and a urethane prepolymer used for forming a primer layer of such an OA roller.

Background Art

[0002] Image formation using the electrophotographic method generally involves (a) uniformly charging the surface of an organic photoreceptor (OPC) drum using a charging roller, (b) irradiating the charged OPC drum with a laser to cancel the charge in the irradiated area, thereby creating an electrostatic latent image on the surface of the OPC drum, (c) electrostatically adhering (developing) toner to the surface of the OPC drum using a developing roller, (d) transferring the toner from the surface of the OPC drum to the surface of paper using a transfer roller, (e) fixing the toner to the paper using a fixing roller to be performed.

[0003] Thus, various rollers such as a charging roller, a developing roller, a transfer roller, a fixing roller, etc. (hereinafter, these are also collectively referred to as "OA rollers") are used in an image forming apparatus using the electrophotographic method. OA rollers generally include a metal shaft and an elastic layer formed on the surface of the metal shaft. The elastic layer generally consists of a low-hardness polymer elastic foam. Another layer having predetermined properties may be formed on the surface of the elastic layer. For example, when the roller surface consists of a low-hardness polymer elastic foam, toner may adhere to the roller surface, which may cause toner filming (a phenomenon in which toner thinly adheres to the surface of the photoreceptor drum). In such a case, a solid layer for reducing the friction coefficient may be formed on the surface of the elastic layer.

[0004] Regarding such a roller for OA and its manufacturing method, various proposals have been made conventionally. For example, in Patent Document 1, (a) An elastic layer composed of a foam layer and a skin layer is formed on the surface of a metal shaft, (b) An ultraviolet curable resin composition is applied to the surface of the skin layer so as to have a thickness of 100 μm, (c) The coating film is cured by irradiating it with ultraviolet rays to form a solid layer A manufacturing method of a foam roller is disclosed.

[0005] In the same document, (A) When forming a solid layer by applying a solvent-based paint or an aqueous paint and drying it with hot air, a long drying line is required, and the quality of the solid layer is not stable. Also, (B) When forming a solid layer using an ultraviolet curable resin composition, a long drying line is not required, and the quality is also stabilized is described.

[0006] In Patent Document 2, (a) A base material layer containing a foamed resin and a pigment that absorbs ultraviolet rays is formed on the outer peripheral surface of a conductive shaft, (b) A primer layer containing a non-ultraviolet curable elastomer is formed on the outer peripheral surface of the base material layer, (c) An elastomer layer containing an ultraviolet curable elastomer is formed on the outer peripheral surface of the primer layer An OA roller obtained thereby is disclosed.

[0007] In the same document, it is described that when a non-ultraviolet curable primer layer is interposed between a base material layer containing a pigment that absorbs ultraviolet rays and an ultraviolet curable elastomer layer, the curing failure of the raw material of the ultraviolet curable elastomer is suppressed.

[0008] Among the rollers for OA, conductivity is required for transfer rollers, developing rollers, charging rollers, etc. When the elastic layer (base material layer) formed on the surface of a metal shaft consists only of a foamed resin, the conductivity is insufficient, so a conductive material is usually added to the elastic layer. Also, when the outermost surface of the elastic layer consists of a foamed resin, the electrostatic force is insufficient in the pore part, and there may occur a phenomenon (a missing phenomenon) where toner is not partially transferred and a part of the image is missing. Therefore, a surface layer (elastomer layer) that does not contain pores is formed on the outermost surface of the elastic layer (base material layer) made of a foamed resin.

[0009] When forming an elastomer layer on the surface of the base material layer, if an ultraviolet-curable elastomer is used as the elastomer layer, the elastomer layer can be formed in a short time. However, when the conductive material contained in the base material layer is a pigment that absorbs ultraviolet rays such as carbon, if an ultraviolet-curable elastomer is used as the elastomer layer, there is a problem that poor curing occurs at the interface between the base material layer and the elastomer layer, and sufficient adhesive strength cannot be ensured. On the other hand, in order to solve this problem, if a non-ultraviolet-curable elastomer such as a thermosetting elastomer or a moisture-curing elastomer is used as the elastomer layer, there is a problem that the curing takes a long time.

[0010] In contrast, as described in Patent Document 2, when forming an elastomer layer made of an ultraviolet-curable elastomer on the surface of a base material layer containing a pigment that absorbs ultraviolet rays, if a primer layer made of a non-ultraviolet-curable elastomer is interposed between the base material layer and the elastomer layer, poor curing of the elastomer layer can be avoided. Also, compared with the case where the entire elastomer layer and primer layer are formed using a non-ultraviolet-curable elastomer, the curing time can be shortened.

[0011] However, the method described in Patent Document 2 has a longer curing time compared to the case where the entire elastomer layer and primer layer are formed using an ultraviolet-curable elastomer. Also, there is a risk that solvents and / or low-molecular-weight additives remaining in the non-ultraviolet-curable elastomer will bleed out during the use of the OA roller. Furthermore, it is difficult to control the conductivity of the non-ultraviolet-curable elastomer compared to the ultraviolet-curable elastomer.

Prior Art Documents

Patent Documents

[0012]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0013] The problem to be solved by the present invention is, in an OA roller including a base material layer containing a pigment that absorbs ultraviolet rays and an elastomer layer containing an ultraviolet-curable elastomer, to suppress adhesion failure of the elastomer layer without increasing the manufacturing time. Another problem to be solved by the present invention is, in such an OA roller, to facilitate the control of conductivity.

[0014] Another problem to be solved by the present invention is, in such an OA roller, to reduce the bleed-out of solvents and / or low-molecular-weight additives and the resulting environmental risks. Furthermore, another problem to be solved by the present invention is to provide a urethane prepolymer suitable for the manufacture of such an OA roller.

Means for Solving the Problems

[0015] In order to solve the above problems, the urethane prepolymer according to the present invention is A urethane prepolymer having NCO groups at its terminals is obtained by reacting a polyol with a polyisocyanate, and the NCO groups of the urethane prepolymer having NCO groups at its terminals are sealed with an ultraviolet-curable monoalcohol and a non-ultraviolet-curable monoalcohol, satisfies the following formulas (1) to (4). 0.30 ≦ Y1 / X ≦ 0.70 …(1) 0.10 ≦ Y2 / X ≦ 0.50 …(2) 0.05 ≦ Y3 / X ≦ 0.40 …(3) 1.00 ≦ (Y1 + Y2 + Y3) / X ≦ 1.05 …(4) However, X is the number of moles of NCO groups contained in the polyisocyanate, Y1 is the number of moles of OH groups contained in the polyol, Y2 is the number of moles of OH groups contained in the ultraviolet-curable monoalcohol, Y3 is the number of moles of OH groups contained in the non-ultraviolet-curable monoalcohol.

[0016] The non-ultraviolet-curable monoalcohol preferably contains a conductive monoalcohol composed of an ionic compound.

[0017] The roller for OA according to the present invention includes a shaft, a base material layer formed on the outer peripheral surface of the shaft, a primer layer formed on the outer peripheral surface of the base material layer, and an elastomer layer formed on the outer peripheral surface of the primer layer and is provided with The base material layer contains a foamed resin and a pigment that absorbs ultraviolet rays and is dispersed in the foamed resin, The primer layer contains a first ultraviolet-curable elastomer, The elastomer layer contains a second ultraviolet-curable elastomer, The first ultraviolet-curable elastomer contains an elastomer obtained by photopolymerizing a raw material containing the urethane prepolymer according to the present invention.

Advantages of the Invention

[0018] When the NCO groups of the NCO-terminated urethane prepolymer are blocked with an appropriate amount of an ultraviolet-curable monoalcohol and a non-ultraviolet-curable monoalcohol, a urethane prepolymer (ultraviolet semi-curable urethane prepolymer) in which the hardness of the polymer does not become excessively high even when photo-polymerized can be obtained. This is presumably because an appropriate amount of the non-ultraviolet-curable monoalcohol is bonded to the ends of the urethane prepolymer, so that the molecular weight of the polymer does not become excessively high even when photo-polymerized.

[0019] When a primer layer (a primer layer made of a first ultraviolet-curable elastomer) obtained by photo-polymerizing such a urethane prepolymer is interposed between a base material containing a pigment that absorbs ultraviolet rays and an elastomer layer, the elastomer layer becomes difficult to peel off. This is presumably because the primer layer functions as an adhesive layer because the primer layer has appropriate hardness and tackiness.

[0020] The urethane prepolymer according to the present invention can be cured by irradiation with ultraviolet rays, so the curing time is short. Further, by increasing or decreasing the ratio of the conductive monoalcohol in the non-ultraviolet-curable monoalcohol, the conductivity of the polymer after curing can be easily controlled. Furthermore, since the urethane prepolymer according to the present invention can be used without dilution with a solvent, bleed-out of the solvent and / or low-molecular-weight additives and the resulting environmental risks can be suppressed.

Brief Description of the Drawings

[0021]

Figure 1

[0022] Hereinafter, an embodiment of the present invention will be described in detail. [1. Urethane prepolymer] The urethane prepolymer (ultraviolet semi-curable urethane prepolymer) according to the present invention is React a polyol with a polyisocyanate to obtain an NCO group-terminated urethane prepolymer, and seal the NCO groups of the NCO group-terminated urethane prepolymer with an ultraviolet curable monoalcohol and a non-ultraviolet curable monoalcohol. It is obtained by the following.

[0023] [1.1. Components] [1.1.1. Polyol] [A. Materials] The polyol is one of the main raw materials for producing the NCO group-terminated urethane prepolymer. In the present invention, the type of polyol is not particularly limited, and the optimal material can be selected according to the purpose. Also, in the present invention, the functionality number of the polyol is not particularly limited, and the optimal value can be selected according to the purpose. Furthermore, in the present invention, any one type of polyol may be used, or two or more types of polyols may be used in combination.

[0024] Examples of the polyol include (a) Polyether polyol obtained by addition polymerization of an alkylene oxide to an initiator, (b) Polyester polyol obtained by dehydration condensation of a carboxylic acid and a polyhydric alcohol, (c) Polymer polyol in which polymer fine particles obtained by copolymerizing acrylonitrile or styrene are dispersed in a polyether polyol and the like.

[0025] [B. Number average molecular weight] In the present invention, the number average molecular weight of the polyol is not particularly limited, and the optimal value can be selected according to the purpose. Generally, if the number average molecular weight of the polyol is too small, the hardness of the polymer obtained by photopolymerizing the urethane prepolymer may become excessively high, and the followability to the substrate may deteriorate. Therefore, the number average molecular weight of the polyol is preferably 1000 or more. The number average molecular weight is more preferably 1500 or more, or 2000 or more. On the other hand, if the number average molecular weight of the polyol is too large, the viscosity of the urethane prepolymer may become excessively high, and it may be difficult to apply it to the substrate surface. Therefore, the number average molecular weight of the polyol is preferably 6000 or less. The number average molecular weight is more preferably 5500 or less, or 5000 or less.

[0026] [1.1.2. Polyisocyanate] [A. Materials] Polyisocyanate is another main raw material for producing NCO group-terminated urethane prepolymer. In the present invention, the type of polyisocyanate is not particularly limited, and the most suitable material can be selected according to the purpose. Also, in the present invention, the functional group number of the polyisocyanate is not particularly limited, and the most suitable value can be selected according to the purpose. Furthermore, in the present invention, any one kind of polyisocyanate may be used, or two or more kinds of polyisocyanates may be used in combination.

[0027] Examples of polyisocyanates include (a) aromatic isocyanate compounds, aliphatic isocyanate compounds, or alicyclic isocyanate compounds, (b) modified products of the above compounds and the like.

[0028] Examples of aromatic isocyanate compounds include, for example, diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate, tolylene diisocyanate (TDI), Naphthalene diisocyanate (NDI), p-phenylene diisocyanate (PPDI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), tolylene diisocyanate (TODI) and the like can be mentioned.

[0029] Examples of the aliphatic isocyanate compound include, for example, hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), lysine triisocyanate (LTI) and the like can be mentioned.

[0030] Examples of the alicyclic isocyanate compound include, for example, isophorone diisocyanate (IPDI), cyclohexyl diisocyanate (CHDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H 12 MDI) and the like can be mentioned.

[0031] Examples of the modified isocyanate compound include, for example, urethane-modified products, dimers, trimers, carbodiimide-modified products, allophanate-modified products, burette-modified products, urea-modified products, isocyanurate-modified products, oxazolidone-modified products, isocyanate group-terminated prepolymers, and the like of the isocyanate compound.

[0032] [B. Molecular weight] In the present invention, the molecular weight of the polyisocyanate is not particularly limited, and an optimum value can be selected according to the purpose.

[0033] [1.1.3. UV-curable monoalcohol] The "UV-curable monoalcohol" refers to an organic compound having one or more photopolymerizable functional groups and one OH group in the molecule. The UV-curable monoalcohol has a function of sealing the NCO group of the NCO group-terminated urethane prepolymer and at the same time adding a photopolymerizable functional group to the urethane prepolymer.

[0034] In the present invention, the type of the ultraviolet curable monool is not particularly limited, and an optimal material can be selected according to the purpose. Furthermore, in the present invention, any one kind of ultraviolet curable monool may be used, or two or more kinds of ultraviolet curable monools may be used in combination.

[0035] Examples of the photopolymerizable functional group include an allyl group, a vinyl ether group, an acrylate group, a methacrylate group, etc. The ultraviolet curable monool is particularly preferably a monool having at least one functional group selected from the group consisting of an allyl group, a vinyl ether group, an acrylate group, and a methacrylate group.

[0036] Examples of the ultraviolet curable monool having an allyl group include allyl alcohol, allyl ether glycol, hydroxyethyl allyl ether, etc. Examples of the ultraviolet curable monool having a vinyl ether group include hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, etc.

[0037] Examples of the ultraviolet curable monool having an acrylate group include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, etc. Examples of the ultraviolet curable monool having a methacrylate group include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, etc.

[0038] [1.1.4. Non-ultraviolet curable monool] "Non-UV curable monoalcohol" refers to an organic compound that has one OH group in the molecule but does not have a photopolymerizable functional group. The non-UV curable monoalcohol has a function (crosslinking adjustment function) of suppressing an excessive increase in the molecular weight of the polymer obtained by simultaneously blocking the NCO group of the NCO group-terminated urethane prepolymer and photopolymerizing the urethane prepolymer.

[0039] Non-UV curable monoalcohols are roughly classified into conductive monoalcohols and non-conductive monoalcohols. "Conductive monoalcohol" refers to a monoalcohol composed of an ionic compound and not having a photopolymerizable functional group. The conductive monoalcohol has a function of reducing the volume resistivity of the polymer obtained by photopolymerizing the urethane prepolymer. "Non-conductive monoalcohol" refers to a monoalcohol composed of a non-ionic compound and not having a photopolymerizable functional group. The non-conductive monoalcohol does not have a function of reducing the volume resistivity of the polymer obtained by photopolymerizing the urethane prepolymer.

[0040] In the present invention, the type of non-UV curable monoalcohol is not particularly limited, and an optimal material can be selected according to the purpose. Furthermore, in the present invention, any one type of non-UV curable monoalcohol may be used, or two or more types of non-UV curable monoalcohols may be used in combination.

[0041] Examples of the conductive monoalcohol include (a) Hydroxyl group-containing quaternary ammonium salt type cationic conductive material (for example, "Cation IN" manufactured by NOF Corporation), (b) Hydroxyl group-containing imidazolium salt type cationic conductive material, (c) Hydroxyl group-containing pyridinium salt type cationic conductive material, (d) Hydroxyl group-containing pyrrolidinium salt type cationic conductive material, (e) Hydroxyl group-containing phosphonium salt type cationic conductive material, and the like.

[0042] Examples of non-conductive monoalcohols include isopropyl alcohol (IPA), methanol, ethanol, propanol, butanol, and the like.

[0043] [1.2. Reaction] [1.2.1. Reaction conditions] First, under the condition of excess NCO groups, a polyol and a polyisocyanate are reacted to obtain an NCO group-terminated urethane prepolymer. Next, the NCO groups of the NCO group-terminated urethane prepolymer are blocked with an ultraviolet curable monoalcohol and a non-ultraviolet curable monoalcohol, thereby obtaining the urethane prepolymer according to the present invention.

[0044] In the present invention, the reaction conditions between the polyol and the polyisocyanate are not particularly limited, and optimal conditions can be selected according to the purpose. Similarly, the reaction conditions between the NCO group-terminated urethane prepolymer and the ultraviolet curable monoalcohol and the non-ultraviolet curable monoalcohol are not particularly limited, and optimal conditions can be selected according to the purpose.

[0045] [1.2.2. Raw material formulation] The urethane prepolymer according to the present invention needs to satisfy the following formulas (1) to (4). 0.30 ≦ Y1 / X ≦ 0.70 …(1) 0.10 ≦ Y2 / X ≦ 0.50 …(2) 0.05 ≦ Y3 / X ≦ 0.40 …(3) 1.00 ≦ (Y1 + Y2 + Y3) / X ≦ 1.05 …(4) However, X is the number of moles of NCO groups contained in the polyisocyanate, Y1 is the number of moles of OH groups contained in the polyol, Y2 is the number of moles of OH groups contained in the ultraviolet curable monoalcohol, Y3 is the number of moles of OH groups contained in the non-ultraviolet curable monoalcohol.

[0046] In addition, the ultraviolet semi-curable urethane prepolymer according to the present invention preferably further satisfies the following formula (5). 0.00 ≦ Y 31 / Y3 ≦ 1.00 …(5) However,[[]] Y3 represents the number of moles of OH groups contained in the non-ultraviolet curable monool, Y 31 represents the number of moles of OH groups contained in the conductive monool.

[0047] [A. Formula (1)] In formula (1), Y1 / X represents the ratio of the number of moles of OH groups in the polyol to the total number of moles of NCO groups. If Y1 / X becomes too small, unreacted polyisocyanate may remain excessively. Therefore, Y1 / X needs to be 0.30 or more. Y1 / X is preferably 0.35 or more, 0.40 or more, 0.45 or more, 0.46 or more, or 0.47 or more. On the other hand, if Y1 / X becomes too large, unreacted polyol may remain excessively. Therefore, Y1 / X needs to be 0.70 or less. Y1 / X is preferably 0.65 or less, 0.60 or less, 0.55 or less, 0.54 or less, or 0.53 or less.

[0048] [B. Formula (2)] In formula (2), Y2 / X represents the ratio of the number of moles of OH groups in the ultraviolet curable monool to the total number of moles of NCO groups. If Y2 / X becomes too small, the hardness of the polymer obtained by photopolymerizing the urethane prepolymer may become excessively low. Therefore, Y2 / X needs to be 0.10 or more. Y2 / X is preferably 0.15 or more, 0.20 or more, 0.22 or more, or 0.24 or more. On the other hand, if Y2 / X becomes too large, the hardness of the polymer after photopolymerization may become excessively high. Therefore, Y2 / X needs to be 0.50 or less. Y2 / X is preferably 0.45 or less, 0.40 or less, 0.38 or less, or 0.36 or less.

[0049] [C. Formula (3)] In formula (3), Y3 / X represents the ratio of the number of moles of OH groups in the non-UV-curable monoalcohol to the total number of moles of NCO groups. If Y3 / X becomes too small, the hardness of the polymer after photopolymerization may become excessively high. Therefore, Y3 / X needs to be 0.05 or more. Y3 / X is preferably 0.10 or more, or 0.15 or more. On the other hand, if Y3 / X becomes too large, the hardness of the polymer after photopolymerization may excessively decrease. Therefore, Y3 / X needs to be 0.40 or less. Y3 / X is preferably 0.35 or less, 0.30 or less, 0.25 or less, or 0.20 or less.

[0050] [D. Formula (4)] In formula (4), (Y1 + Y2 + Y3) / X represents the ratio of the number of moles of OH groups contained in the raw materials to the number of moles of NCO groups. Ideally, it is preferable that all NCO groups contained in the NCO-group-terminated urethane prepolymer are blocked with the UV-curable monoalcohol and the non-UV-curable monoalcohol. However, if the blending ratio of the raw materials is inappropriate, unreacted OH groups or NCO groups may remain.

[0051] If there are unreacted NCO groups, the environmental load may increase. Therefore, (Y1 + Y2 + Y3) / X needs to be 1.00 or more. On the other hand, if the unreacted OH groups become excessive, there is a risk that low-molecular-weight components will bleed out from the polymer after photopolymerization. Therefore, (Y1 + Y2 + Y3) / X needs to be 1.05 or less. (Y1 + Y2 + Y3) / X is preferably 1.04 or less, or 1.03 or less.

[0052] [E. Formula (5)] In formula (5), Y 31 / Y3 represents the ratio of the number of moles of OH groups in the conductive monoalcohol to the number of moles of OH groups in the non-UV-curable monoalcohol. Y 31 / Y3 may be zero. However, if Y 31 / Y3 becomes too small, the volume resistivity of the polymer after photopolymerization may excessively increase. Therefore, Y31 / Y3 is preferably 0.10 or more. Y 31 / Y3 is more preferably 0.12 or more, or 0.14 or more. On the other hand, Y 31 / Y3 may be 1.00. However, Y 31 Even if / Y3 is made larger than necessary, there is no difference in effect and no practical benefit. Also, Y 31 If / Y3 becomes too large, it may lead to higher costs. Therefore, Y 31 / Y3 is preferably 0.90 or less. Y 31 / Y3 is more preferably 0.70 or less, 0.50 or less, or 0.30 or less.

[0053] [2. OA Roller] Fig. 1 shows a front view (left figure) and a cross-sectional view taken along line A-A' (right figure) of the OA roller according to the present invention. In Fig. 1, the OA roller 10 includes a shaft 12, a base material layer 14 formed on the outer peripheral surface of the shaft 12, a primer layer 16 formed on the outer peripheral surface of the base material layer 14, and an elastomer layer 18 formed on the outer peripheral surface of the primer layer 16 and is provided with. An OC layer (not shown) may further be formed on the surface of the elastomer layer 18.

[0054] [2.1. Shaft] In the present invention, the material of the shaft 12 is not particularly limited. The shaft 12 may be made of a conductive material or a non-conductive material. Examples of the material of the shaft 12 include, for example, (a) metals such as stainless steel, aluminum alloy, copper alloy, and magnesium alloy, (b) a composite material in which a conductive material is dispersed in a matrix made of resin, (c) a composite material in which a conductive film is formed on the surface of resin, (d) non-conductive resin, and so on. In particular, the shaft 12 is preferably a metal shaft. This is because a metal shaft has higher conductivity and strength and lower cost compared to shafts made of other materials.

[0055] The diameter and length of the shaft 12 are not particularly limited, and optimal values can be selected according to the purpose. The shaft 12 may be a solid shaft or a hollow shaft.

[0056] [2.2. Substrate layer] A substrate layer 14 is formed on the outer peripheral surface of the shaft 12. In the present invention, the substrate layer 14 contains a foamed resin and a pigment that absorbs ultraviolet rays and is dispersed in the foamed resin. The substrate layer 14 may consist only of the foamed resin and the pigment, or may further contain an ion conductive material A in addition to these.

[0057] [2.2.1. Materials] [A. Foamed resin] In the present invention, the type of the foamed resin is not particularly limited. Examples of the material of the foamed resin include polyurethane, silicone rubber, ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), natural rubber, styrene-butadiene rubber (SBR), butadiene rubber, isoprene rubber, polynorbornene rubber, butyl rubber, chloroprene rubber, acrylic rubber, epichlorohydrin rubber (ECO), ethylene-vinyl acetate copolymer (EVA), and the like.

[0058] Among these, the foamed resin is preferably foamed polyurethane. The OA roller 10 repeatedly makes contact with and separates from the object at high speed during use, and accordingly repeatedly deforms and recovers. At this time, if the restoring force on the surface of the OA roller 10 is weak, the OA roller 10 and the next object may come into contact with the surface remaining concave, and horizontal white streaks or color unevenness may occur in the image. Since the foamed polyurethane has a greater restoring force than other materials, there is an advantage that such white streaks and color unevenness are less likely to occur. Further, the foamed polyurethane also has an advantage of excellent wear resistance.

[0059] In the present invention, the density of the foamed resin is not particularly limited, and an optimal value can be selected according to the purpose. Generally, if the density becomes too small, it may be difficult to hold the primer raw material on the surface of the base material layer 14 when the liquid primer raw material is applied to the surface of the base material layer 14. Therefore, the density is preferably 35 kg / m 3 or more. On the other hand, if the density becomes too large, it may be difficult to produce the foamed resin. Therefore, the density is preferably 800 kg / m 3 or less. The density is more preferably 720 kg / m 3 or less. In the present invention, the "density of the base material layer 14" refers to the density of the foamed resin containing the pigment and, if necessary, the ion conductive material A added.

[0060] The air bubbles contained in the foamed resin are preferably closed cells. This is because when the primer layer 16 is formed on the surface of the base material layer 14, it is difficult for the raw material of the primer layer 16 to penetrate into the inside of the foamed resin. Furthermore, the surface of the base material layer 14 preferably has small irregularities. This is because the smaller the irregularities on the surface of the base material layer 14, the easier it is to fill the concave portions on the surface of the base material layer 14 with the primer.

[0061] [B. Pigment] The base material layer 14 contains a pigment dispersed in the foamed resin. "The pigment is dispersed in the foamed resin" means that (a) the pigment is filled in the gaps between the polymer chains constituting the foamed resin, and / or (b) the pigment is filled in the air bubbles of the foamed resin .

[0062] The pigment is mainly added to color the base material layer 14 in a desired color, to make the discoloration (yellowing) of the foamed resin less noticeable, and to control the conductivity of the base material layer 14. In the present invention, the pigment is made of a material that absorbs ultraviolet rays. The pigment may be a material having high conductivity or a material not having high conductivity. Examples of the pigment include (a) carbon, (b) metal powders such as aluminum, copper, and nickel, (c) conductive metal oxide powders such as tin oxide, titanium oxide, and zinc oxide, and the like. In particular, carbon is preferred as the pigment. This is because the yellowing becomes less noticeable due to the base material layer 14 being colored black, and the conductivity of the base material layer 14 can be controlled relatively easily.

[0063] There are various materials of carbon with different shapes and conductivities. Examples of carbon include (a) carbon blacks with large structures such as acetylene black and ketjen black, which have a large function of increasing the conductivity of the base material layer 14 (hereinafter, these are collectively referred to as "conductive carbon" as well), (b) carbon blacks with small structures such as furnace black, which have a small function of increasing the conductivity of the base material layer 14 (hereinafter, these are collectively referred to as "pigment carbon" as well), (c) graphite powder, (d) carbon fiber and the like.

[0064] [C. Ionic Conductive Material A] When the OA roller 10 is used as a transfer roller, for example, the base material layer 14, the primer layer 16, and the elastomer layer 18 need to have a predetermined conductivity. If the conductivity required for the OA roller 10 can be obtained only by adding a pigment to the base material layer 14 and optimizing the primer layer 16 and the elastomer layer 18 (including optimizing the thickness of each layer), the ionic conductive material A is not necessarily required. On the other hand, if the conductivity required for the OA roller 10 cannot be obtained only by adding a pigment to the base material layer 14 and optimizing the primer layer 16 and the elastomer layer 18, it is preferable to add the ionic conductive material A to the base material layer 14.

[0065] In the present invention, the material of the ionic conductive material A added to the base material layer 14 is not particularly limited. Examples of the ionic conductive material A include the following. (a) Perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluoroacid salts, sulfates, ethyl sulfates, carboxylates, sulfonates and other ammonium salts of tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (for example, lauryltrimethylammonium), hexadecyltrimethylammonium, octadecyltrimethylammonium (for example, stearyltrimethylammonium), benzyltrimethylammonium, modified fatty acid dimethylethylammonium, etc.

[0066] (b) Perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluoroacid salts, trifluoromethylsulfates, sulfonates of alkali metals and alkaline earth metals such as lithium, sodium, potassium, calcium, magnesium, etc. (c) Salts having imidazolium-based ions, pyridinium-based ions, pyrrolidinium-based ions, piperidinium-based ions, phosphonium-based ions as cation species, and having halogen-based ions such as chlorine, bromine, iodine, etc., borate-based ions such as tetrafluoroborate ion, phosphate-based ions such as hexafluorophosphate ion, sulfate-based ions such as bis(trifluoromethanesulfonyl)imide ion as anion species.

[0067] [2.2.2. Content] The content of the pigment contained in the base material layer 14 is not particularly limited, and an optimal content can be selected according to the type of pigment, the presence or absence of the ionic conductive material A, the use of the roller 10 for OA, etc. Similarly, when the base material layer 14 contains the ionic conductive material A, the content of the ionic conductive material A is not particularly limited, and an optimal content can be selected according to the type of pigment, the use of the roller 10 for OA, etc.

[0068] Generally, if the content of the pigment is too small, yellowing is likely to be prominent, or the desired conductivity may not be obtained. Therefore, the content of the pigment is preferably 0.4 mass% or more. On the other hand, if the content of the pigment is excessive, the viscosity of the raw material containing it may increase excessively, and it may be difficult to manufacture the base material layer 14. Also, if the content of the pigment is excessive, the base material layer 14 may become brittle. Therefore, the content of the pigment is preferably 19.6 mass% or less.

[0069] The content of the ionic conductive material A is not particularly limited, and an optimal content can be selected according to the purpose. Generally, the higher the content of the ionic conductive material A, the higher the conductivity obtained. On the other hand, if the content of the ionic conductive material A is excessive, the mechanical properties of the base material layer 14 may deteriorate. Specifically, the content of the ionic conductive material A is preferably 0.01 mass% or more and 10.0 mass% or less.

[0070] [2.2.3. Thickness] The thickness of the base material layer 14 is not particularly limited, and an optimal thickness can be selected according to the purpose. The thickness of the base material layer 14 is usually about 1 mm to 10 mm.

[0071] [2.3. Primer layer] A primer layer 16 is formed on the outer peripheral surface of the base material layer 14. The primer layer 16 is inserted between the base material layer 14 and the elastomer layer 18 in order to suppress poor curing of the elastomer layer 18.

[0072] [2.3.1. Material] In the present invention, the primer layer 16 contains a first ultraviolet curable elastomer. The "first ultraviolet curable elastomer" refers to an elastomer obtained by photopolymerizing a raw material containing a urethane prepolymer according to the present invention. The first ultraviolet curable elastomer is preferably an elastomer obtained by applying a raw material solution A containing a urethane prepolymer (ultraviolet semi-curable urethane prepolymer) according to the present invention to the surface of the base material layer 14, irradiating the coating film made of the raw material solution A with ultraviolet rays, and performing photopolymerization. Details of the urethane prepolymer (ultraviolet semi-curable urethane prepolymer) are as described above, and thus the description is omitted.

[0073] The raw material solution A for forming the primer layer 16 may contain only the urethane prepolymer, or may contain other components. Examples of other components include (a) A polythiol having a thiol group for causing an en-thiol reaction with a photopolymerizable functional group of the urethane polymer, (b) An antioxidant for suppressing oxidation of the primer layer 16, (c) A light stabilizer for suppressing photo-oxidative degradation of the primer layer 16, (d) An antifoaming agent for suppressing generation of bubbles in the primer layer 16, (e) A photoinitiator for generating radicals, (f) An ionic conductive material C for imparting conductivity to the primer layer 16 and the like.

[0074] The types of the polythiol, antioxidant, light stabilizer, antifoaming agent, and photoinitiator are not particularly limited, and an optimal material can be selected according to the purpose. Also, details of the ionic conductive material C are the same as those of the ionic conductive material A, and thus the description is omitted.

[0075] However, the primer layer 16 needs to contain no pigment that absorbs ultraviolet rays. This is because if the primer layer 16 contains a pigment that absorbs ultraviolet rays, it will not only be difficult to cure the raw material solution A for forming the primer layer 16 by ultraviolet rays, but also be difficult to cure the raw material solution B for forming the elastomer layer 18 formed on the primer layer 16 by ultraviolet rays. Note that the primer layer 16 may be made of a foamed material or a non-foamed material. However, when the primer layer 16 is made of a foamed material, if the raw material of the elastomer layer 18 soaks into the bubbles in the primer layer 16 and the raw material of the elastomer layer 18 comes into contact with the base material layer 14, the curing of the raw material may be insufficient. In order to suppress such infiltration of the raw material, the primer layer 16 is preferably made of a non-foamed material.

[0076] [2.3.2. Thickness] As described later, the primer layer 16 is formed by applying the raw material solution A for forming the primer layer 16 on the surface of the base material layer 14 and curing the coating film. In this case, since the base material layer 14 contains bubbles, a part of the raw material solution A may soak into the bubbles in the base material layer 14, and the raw material solution A may cure in the bubbles. In the present invention, the "thickness of the primer layer 16" refers to the distance from the outermost surface of the base material layer 14 to the outermost surface of the primer layer 16, and does not include the thickness of the region where the raw material solution A soaks into the bubbles in the base material layer 14 and cures.

[0077] The thickness of the primer layer 16 affects the performance and cost of the OA roller 10. If the thickness of the primer layer 16 becomes too thin, poor curing of the elastomer layer 18 may occur when forming the elastomer layer 18. Therefore, the thickness of the primer layer 16 is preferably more than 0 mm. More preferably, the thickness is 0.2 mm or more. On the other hand, even if the thickness of the primer layer 16 is made thicker than necessary, there is no difference in effect and no practical benefit. Therefore, the thickness of the primer layer 16 is preferably 0.8 mm or less.

[0078] [2.4. Elastomer layer] An elastomer layer 18 is formed on the outer peripheral surface of the primer layer 16. The elastomer layer 18 is formed to suppress the shortage of the electrostatic force caused by the unevenness of the base material layer 14. In the present invention, the elastomer layer 18 contains a second ultraviolet curable elastomer. The elastomer layer 18 may consist only of the second ultraviolet curable elastomer, or may further contain an ion conductive material B in addition to this.

[0079] [2.4.1. Materials] [A. Second ultraviolet curable elastomer] The elastomer layer 18 contains a second ultraviolet curable elastomer. The second ultraviolet curable elastomer is not particularly limited as long as it can be cured using ultraviolet rays. The second ultraviolet curable elastomer includes those having relatively high conductivity and those having relatively low conductivity. Any of them may be used as the material of the elastomer layer 18.

[0080] The elastomer layer 18 is particularly A raw material solution B containing a second urethane prepolymer having an allyl group, a vinyl ether group, an acrylate group, or a methacrylate group as a terminal functional group and a polythiol having a thiol group is applied to the surface of the primer layer, The coating film made of the raw material solution B is irradiated with ultraviolet rays to cause an ene-thiol reaction Those containing an elastomer obtained in this way are preferred. In order to effectively carry out the reaction between an allyl group or the like and a thiol group, it is preferable to add a photopolymerization initiator to the raw material solution B.

[0081] Specifically, the second urethane prepolymer is preferably produced by the same method as the urethane prepolymer (ultraviolet semi-curable urethane prepolymer) according to the present invention, except that the raw materials are blended so that Y3 / X is less than 0.05. Y3 / X is preferably 0.01 or less. Examples of the material of the elastomer layer 18 other than those described above include, for example, a composition containing a (meth)acrylate oligomer and an ultraviolet polymerization initiator.

[0082] [B. Ion conductive material B] As described above, when the OA roller 10 is applied to, for example, a transfer roller, the base material layer 14, the primer layer 16, and the elastomer layer 18 need to have a predetermined conductivity. If the conductivity required for the OA roller 10 can be obtained only by optimizing the material of the second ultraviolet curable elastomer constituting the elastomer layer 18 and optimizing the base material layer 14 and the primer layer 16 (including optimizing the thickness of each layer), the ion conductive material B is not necessarily required. On the other hand, when the conductivity required for the OA roller 10 cannot be obtained only by optimizing the material of the second ultraviolet curable elastomer and optimizing the base material layer 14 and the primer layer 16, it is preferable to add the ion conductive material B to the elastomer layer 18.

[0083] In the present invention, the material of the ion conductive material B added to the elastomer layer 18 is not particularly limited. When the base material layer 14 contains the ion conductive material A, the ion conductive material B may be the same material as the ion conductive material A or a different material. Since other points regarding the ion conductive material B are the same as those of the ion conductive material A, the description thereof is omitted.

[0084] [2.4.2. Content] When the elastomer layer 18 contains the ion conductive material B, the content of the ion conductive material B is not particularly limited, and an optimum content can be selected according to the type of the second ultraviolet curable elastomer, the use of the OA roller 10, and the like.

[0085] Generally, if the content of the ion conductive material B is too small, the conductivity may decrease. Therefore, the content of the ion conductive material B is preferably 0.05 mass% or more. On the other hand, when the content of the ionic conductive material B becomes excessive, the mechanical properties of the elastomer layer 18 may deteriorate. Therefore, the content of the ionic conductive material B is preferably 10.0 mass% or less.

[0086] [2.4.3. Thickness] The thickness of the elastomer layer 18 is not particularly limited, and an optimal thickness can be selected according to the purpose. Generally, when the thickness of the elastomer layer 18 becomes too thin, the elastomer layer 18 may peel off when polishing the surface of the elastomer layer 18 after curing the elastomer layer 18. Therefore, the thickness of the elastomer layer 18 is preferably 0.5 mm or more. On the other hand, even if the thickness of the elastomer layer 18 is made thicker than necessary, there is no difference in the effect and no practical benefit. Therefore, the thickness of the elastomer layer 18 is preferably 5.0 mm or less. The thickness is more preferably 4.0 mm or less.

[0087] [2.5. OC Layer] An OC layer (not shown) may be further formed on the surface of the elastomer layer 18. Here, the "OC layer" refers to a layer (surface coating layer) formed on the surface of the elastomer layer 18 for the purpose of imparting antifouling properties to the OA roller 10. The material of the OC layer is not particularly limited, and an optimal material can be used according to the purpose. Examples of the material of the OC layer include aqueous urethane paints. Also, the thickness of the OC layer is not particularly limited, and an optimal thickness can be selected according to the purpose. Specifically, the thickness of the OC layer is preferably 0.5 μm to 40 μm.

[0088] [2.6. Conductivity (Volume Resistivity) of OA Roller] The "volume resistivity" refers to a value calculated from the current value flowing between the outermost surfaces of the shaft 12 - OA roller 10 when a current is passed between the outermost surfaces of the shaft 12 - OA roller 10 under the conditions of temperature: 22°C ± 3°C, relative humidity: 55% ± 5%, and voltage: 100V. The volume resistivity of the OA roller 10 can be controlled by the composition and thickness of each layer.

[0089] The volume resistivity of the OA roller 10 is not particularly limited, and an optimum value can be selected according to the purpose. Specifically, the volume resistivity of the OA roller 10 is preferably 3 (logΩ) or more and 10 (logΩ) or less.

[0090] [2.7. Applications] The OA roller 10 according to the present invention can be used in various applications. The OA roller 10 according to the present invention can be used, for example, as a transfer roller, a charging roller, a toner supply roller, a developing roller, a fixing roller, a paper feed roller, a paper discharge roller, and the like.

[0091] [3. Manufacturing method of OA roller] The OA roller 10 according to the present invention (a) A base material layer 14 is formed on the outer peripheral surface of the shaft 12, (b) A primer layer 16 is formed on the outer peripheral surface of the base material layer 14, (c) An elastomer layer 18 is formed on the outer peripheral surface of the primer layer 16, (d) If necessary, an OC layer is further formed on the outer peripheral surface of the elastomer layer 18 and can be manufactured thereby.

[0092] [3.1. First step] First, a base material layer 14 is formed on the outer peripheral surface of the shaft 12 (first step). In the present invention, the method for forming the base material layer 14 is not particularly limited. Examples of the method for forming the base material layer 14 include (a) A cylindrical foam containing a foamed resin is produced, a shaft is inserted into the through-hole of the foam, and the foam and the shaft are adhered, (b) A shaft is erected at the center of a cylindrical mold, a raw material of a foamed resin is poured into the gap between the inner wall surface of the mold and the shaft, and the raw material is foamed and cured in the mold, and the like.

[0093] Also, as a method for manufacturing a foam containing a pigment and / or an ionic conductive material A, for example, (a) A method of adding a pigment and / or an ionic conductive material A to a raw material of a foamable resin in advance and foaming and curing the raw material; (b) A method of producing a foam using a raw material of a foamable resin that does not contain a pigment and an ionic conductive material A, immersing the foam in a dispersion liquid in which the pigment and / or the ionic conductive material A is dispersed, pulling the foam out of the dispersion liquid, and drying it; etc.

[0094] The composition of the raw material for producing the foamable resin is not particularly limited, and an optimal composition can be selected according to the type of the foamable resin. For example, when the foamable resin is made of foamed polyurethane, it is preferable to use a raw material in which a polyol, an isocyanate, a foam stabilizer, a resinification catalyst, a pigment, and an ionic conductive material A are blended at a predetermined ratio. By mechanically foaming and curing by mixing such a raw material with a mixer while blowing an inert gas, a foam made of foamed polyurethane containing a predetermined amount of a pigment and an ionic conductive material A can be produced.

[0095] Alternatively, a raw material in which a polyol, an isocyanate, a foam stabilizer, a resinification catalyst, a foaming agent, a foaming catalyst, a pigment, and an ionic conductive material A are blended at a predetermined ratio may be used. When such a raw material is poured into a mold and heated to a predetermined temperature, foaming and curing occur, and a foam made of foamed polyurethane containing a predetermined amount of a pigment and / or an ionic conductive material A can be produced.

[0096] [3.2. Second Step] Next, a primer layer 16 is formed on the outer peripheral surface of the base material layer 14. The primer layer 16 can be formed, for example, (a) by applying a raw material solution A containing a raw material of a first ultraviolet-curable elastomer (specifically, the urethane prepolymer according to the present invention) to the surface of the base material layer 14; (b) irradiating the coating film made of the raw material solution A with ultraviolet rays to cause photopolymerization; and thereby forming it. The formation conditions of the primer layer 16 are not particularly limited, and the optimal conditions can be selected according to the purpose.

[0097] [3.3. Third step] Next, an elastomer layer 18 is formed on the outer peripheral surface of the primer layer 16. The elastomer layer 18 can be formed, for example, (a) by applying a raw material solution B containing a raw material of a second ultraviolet curable elastomer to the surface of the primer layer 18, (b) irradiating the coating film made of the raw material solution B with ultraviolet rays to cause photopolymerization Thereby it can be formed.

[0098] The composition of the raw material solution B for forming the elastomer layer 18 is not particularly limited, and it is preferable to select an optimal composition according to the type of the second ultraviolet curable elastomer. For example, when the elastomer layer 18 contains an elastomer obtained by photopolymerizing a second urethane prepolymer and a polythiol, the raw material solution B contains (a) a second urethane prepolymer having an allyl group, a vinyl ether group, an acrylate group, or a methacrylate group as a terminal functional group, (b) a polythiol having a thiol group, (c) a photopolymerization initiator, and (d) an ionic conductive material B which are preferably blended in a predetermined ratio.

[0099] The second urethane prepolymer having an allyl group, a vinyl ether group, an acrylate group, or a methacrylate group as a terminal functional group can be produced by adding a compound having an allyl group, a vinyl ether group, an acrylate group, or a methacrylate group to an NCO group-terminated urethane prepolymer synthesized from a polyol and an isocyanate. Examples of the polythiol include esters of mercaptocarboxylic acids and polyhydric alcohols, fatty acid polythiols, aromatic polythiols, and the like. Examples of the photoinitiator include acetophenone-based compounds, benzophenone-based compounds, thioxanthone-based compounds, and the like.

[0100] When a raw material solution B containing a second urethane prepolymer and a polythiol is applied to the surface of the primer layer 16 and the coating film is irradiated with ultraviolet light, the ene-thiol reaction proceeds. As a result, the coating film cures to obtain an elastomer layer 18. After curing, the surface of the elastomer layer 18 is polished using a cylindrical grinding machine to adjust the shape.

[0101] [3.4. Fourth Step] Next, if necessary, an OC layer (surface coating layer) is formed on the surface of the elastomer layer 18. The method for forming the OC layer is not particularly limited, and an optimal method can be selected according to the purpose.

[0102] [5. Function] When a UV-curable monoalcohol is added to an NCO group-terminated urethane prepolymer, a UV-curable urethane prepolymer is obtained. When such a UV-curable urethane prepolymer is directly applied to the outer peripheral surface of a base material layer containing a pigment that absorbs ultraviolet light and a foaming resin, and the coating film is irradiated with ultraviolet light, the surface of the coating film becomes a sufficiently cured layer (cured layer).

[0103] However, in the vicinity of the interface between the base material layer and the coating film, a layer with insufficient curing (incompletely cured layer) is formed. This is considered to be because in the vicinity of the interface between the base material layer and the coating film, the pigment absorbs ultraviolet light or the pigment shields ultraviolet light, so that a sufficient amount of ultraviolet light is not irradiated to the coating film in the vicinity of the interface. Furthermore, when a frictional force acts on the surface of the obtained cured layer, the cured layer easily peels off from the surface of the base material layer. This is considered to be because the hardness difference between the cured layer and the incompletely cured layer is large.

[0104] On the other hand, when the NCO groups of the NCO group-terminated urethane prepolymer are blocked with an ultraviolet curable monoalcohol and a non-ultraviolet curable monoalcohol, a urethane prepolymer (ultraviolet semi-curable urethane prepolymer) in which the hardness of the polymer does not become excessively high even when irradiated with ultraviolet light and subjected to photopolymerization can be obtained. This is presumably because an appropriate amount of the non-ultraviolet curable monoalcohol is bonded to the ends of the urethane prepolymer, so that the molecular weight of the polymer does not become excessively high.

[0105] When such an ultraviolet semi-curable urethane prepolymer is directly applied to the outer peripheral surface of a base material layer containing a pigment that absorbs ultraviolet light and a foamed resin, and the coating film is irradiated with ultraviolet light, the surface of the coating film hardens, but a layer with a lower hardness than the hardened layer (semi-hardened layer) is formed. Therefore, even if an incompletely cured layer is generated in the vicinity of the interface between the base material layer and the coating film, the hardness difference between the semi-hardened layer and the incompletely cured layer becomes smaller. Furthermore, since the semi-hardened layer is composed of a polymer with a smaller molecular weight than the polymer contained in the hardened layer, it exhibits tackiness.

[0106] When such an ultraviolet semi-curable urethane prepolymer is applied to the surface of the base material layer and irradiated with ultraviolet light, a primer layer with an appropriately low hardness and exhibiting tackiness can be obtained. Furthermore, when an ultraviolet curable urethane prepolymer is applied to the surface of the primer layer and irradiated with ultraviolet light, an elastomer layer having sufficient hardness can be obtained. Even when a frictional force acts on the laminate of the base material layer / primer layer / elastomer layer thus obtained, the elastomer layer is difficult to peel off. This is presumably because the primer layer having appropriate hardness and tackiness functions as an adhesive layer.

[0107] The urethane prepolymer (ultraviolet semi-curable urethane prepolymer) according to the present invention can be cured by irradiation with ultraviolet light. Therefore, when this is used for forming the primer layer of an OA roller, the manufacturing time of the OA roller can be shortened.

[0108] In addition, when forming a primer layer using a non-UV-curable elastomer such as a thermosetting elastomer or a moisture-curing elastomer, it is necessary to add an ion conductive material to the raw material of the non-UV-curable elastomer in order to reduce the volume resistivity of the primer layer. However, generally, it is difficult to uniformly disperse the ion conductive material in the raw material of the non-UV-curable elastomer. On the other hand, in the UV semi-curable urethane prepolymer according to the present invention, when the ratio of the conductive monoalcohol in the non-UV-curable monoalcohol is increased or decreased, the conductivity of the primer layer and the OA roller including the same can be easily controlled.

[0109] Furthermore, since the urethane prepolymer (UV semi-curable urethane prepolymer) according to the present invention can be used without dilution with a solvent, it is possible to suppress the bleed-out of the solvent and / or low molecular weight additives, and the environmental risk caused thereby.

Examples

[0110] (Examples 1 to 9, Comparative Examples 1 to 14) [1. Preparation of Samples] [1.1. Preparation of Substrate Layer] [1.1.1. ENDUR (Machine-Foamed Polyurethane Foam)] As the material for the substrate layer, ENDUR (pigment-free, pigment carbon-added, or conductive carbon-added) manufactured by Inoac Corporation was used. A hole for inserting a shaft was made in the material. The shaft was inserted into the hole of the material, and the material and the shaft were adhered. Furthermore, cylindrical polishing of the material surface was performed to obtain a substrate layer. The thickness of the substrate layer was 3.5 to 5.5 mm.

[0111] [1.1.2. UEM-55 (Slab Urethane Foam A)] As the material for the base material layer, UEM-55 manufactured by Inoac Corporation was used. A hole for inserting a shaft was made in the material. Then, for some of the base material layers, a pigment (conductive carbon) was added to the material by an impregnation method. A shaft was inserted into the hole of the material, and the material and the shaft were adhered. Furthermore, cylindrical polishing of the material surface was performed to obtain the base material layer. The thickness of the base material layer was 3.5 to 5.5 mm.

[0112] [1.1.3. EP-70 (Slab Urethane Foam B)] As the material for the base material layer, EP-70 manufactured by Inoac Corporation was used. A hole for inserting a shaft was made in the material. Then, a pigment (conductive carbon) was added to the material by an impregnation method. A shaft was inserted into the hole of the material, and the material and the shaft were adhered. Furthermore, cylindrical polishing of the material surface was performed to obtain the base material layer. The thickness of the base material layer was 3.3 to 5.5 mm.

[0113] [1.1.4. NBR-based Rubber] Acrylonitrile-butadiene rubber (NBR), epichlorohydrin rubber, pigment, foaming agent, crosslinking agent, vulcanization accelerator, vulcanization accelerator assistant, and processing assistant were mixed at a predetermined ratio to obtain a raw material composition. By extruding the obtained raw material composition, a cylindrical molded body (hereinafter also referred to as "precursor of the base material layer") was adhered to the surface of the shaft. Separately, acrylonitrile-butadiene rubber (NBR), vulcanization assistant, mold release agent, vulcanizing agent, and vulcanization accelerator were mixed at a predetermined ratio to obtain a raw material composition. The raw material composition was extruded to obtain a cylindrical molded body (hereinafter also referred to as "precursor of the elastomer layer").

[0114] The cylindrical precursor of the elastomer layer was set in a cylindrical roll forming mold. Then, a shaft with a precursor of the base material layer formed thereon was inserted into the precursor of the elastomer layer. In this state, the precursor of the elastomer layer and the precursor of the base material layer were heated at 160 °C for 40 minutes to crosslink and foam the raw material composition. After cooling, the shaft with the base material layer and the elastomer layer was taken out of the mold. Next, the outer peripheral surface of the elastomer layer was polished with a cylindrical grinding machine to obtain an elastomer layer with a thickness of 2 mm.

[0115] [1.1.2. Preparation of the primer layer] [A. Examples 1 to 9] For Examples 1 to 9, a primer layer was formed on the surface of the base material layer using an ultraviolet semi-curable urethane prepolymer. Table 1 shows the types of raw materials contained in the raw material solutions A1 and A2 used for forming the primer layer, and the compositions of the raw material solutions A1 and A2. Note that A1 is a raw material solution containing a total of about 2 mass% of non-ultraviolet curable monoalcohol. Also, A2 is a raw material solution containing a total of 7 mass% of non-ultraviolet curable monoalcohol.

[0116] First, a polyol, a polyisocyanate, and a resinification catalyst were mixed at a predetermined ratio and reacted to obtain an NCO group-terminated urethane prepolymer. Next, a predetermined amount of a conductive monoalcohol, a non-conductive monoalcohol, and an ultraviolet curable monoalcohol were added to the obtained NCO group-terminated urethane prepolymer and reacted to obtain an ultraviolet semi-curable urethane prepolymer. Further, a predetermined amount of an antioxidant, a light stabilizer, an antifoaming agent, and a photoinitiator were added to the ultraviolet semi-curable urethane prepolymer and mixed to obtain the raw material solutions A1 and A2. These raw material solutions A1 and A2 were applied to the surface of the base material layer, and the coating film was irradiated with ultraviolet rays to be cured. At that time, the application amounts of the raw material solutions A1 and A2 were adjusted to change the thickness of the primer layer. The thickness of the obtained primer layer was 0.2 mm, 0.4 mm, or 0.8 mm.

[0117] [B. Comparative Examples 1 to 7] For Comparative Examples 1 to 7, no primer layer was formed on the surface of the base material layer.

[0118] [C. Comparative Examples 8 to 14] For Comparative Examples 8 to 14, a primer layer was formed using a solvent-volatile urethane-based primer (manufactured by Tosoh Corporation, Niporan (registered trademark) 5230). A predetermined amount of the urethane-based primer was applied to the outer peripheral surface of the base material layer and dried. At that time, the coating amount of the urethane-based primer was adjusted to change the thickness of the primer layer. The thickness of the obtained primer layer was 0.2 to 0.8 mm. Regarding Comparative Example 14, a primer layer was formed using a solvent-volatile urethane-based primer to which an ionic conductive material C was added. As the ionic conductive material C, "Cation IN" manufactured by NOF Corporation was used. The addition amount of the ionic conductive material C (non-ultraviolet curable monoalcohol) was set to an amount such that it was 0.15 mass% with respect to the total mass of the dried primer layer.

[0119] [1.1.3. Preparation of Elastomer Layer] [A. Examples 1 to 9, Comparative Examples 1 to 6, Comparative Examples 8 to 14] Next, an elastomer layer was formed on the outer peripheral surface of the primer layer. A UV-curable raw material was used for forming the elastomer layer. Table 1 shows the types of raw materials contained in the raw material solutions B1 and B2 used for forming the elastomer layer, and the compositions of the raw material solutions B1 and B2.

[0120] First, a polyol, a polyisocyanate, and a resinification catalyst were mixed at a predetermined ratio and reacted to obtain an NCO group-terminated urethane prepolymer. Next, a predetermined amount of a conductive monoalcohol and a UV-curable monoalcohol were added to the obtained NCO group-terminated urethane prepolymer and reacted to obtain a UV-curable urethane prepolymer. Further, a predetermined amount of an antioxidant, a light stabilizer, an antifoaming agent, and a photoinitiator were added to the UV-curable urethane prepolymer and mixed to obtain a raw material solution B1. In addition, a raw material solution B2 containing a UV-curable urethane prepolymer was obtained in the same manner as the raw material solution B1, except that a conductive monoalcohol was not used.

[0121] Raw material solution B1 and raw material solution B2 were mixed so that the mass ratio was 2:1. A predetermined amount of polythiol was added thereto to obtain raw material solution B. This raw material solution B was applied to the surface of the primer layer or the surface of the base material layer, and the coating film was irradiated with ultraviolet rays to be cured. After curing, the outer peripheral surface was polished with a cylindrical polishing machine to obtain an elastomer layer with a thickness of 2 mm.

[0122] [B. Comparative Example 7] Regarding Comparative Example 7, as described above, the base material layer and the elastomer layer were integrally formed.

[0123] [1.1.4. Preparation of OC layer] Except for Comparative Example 2 and Comparative Example 7, after forming the elastomer layer, an OC layer (surface coating) was formed on the outer peripheral surface of the elastomer layer. The OC layer was formed by applying BONDERITE (registered trademark) S-FN T-862A AN manufactured by Henkel Japan so that the film thickness was 5 to 40 μm and drying it.

[0124]

Table 1

[0125] [2. Test method] [2.1. Volume resistivity] The volume resistivity of the roller after forming the base material layer was measured. The measurement conditions were temperature: 22°C ± 3°C, relative humidity: 55% ± 5%, and voltage: 100V.

[0126] [2.2. Adhesion] Using a cylindrical grinding machine, the adhesion of the elastomer layer was evaluated. While rotating the OA roller, the surface of the elastomer layer of the OA roller was ground with a grindstone. Whether the elastomer layer peeled off during the grinding test was evaluated. The grinding conditions were as follows. Grinding device: Cylindrical grinding machine "LEO-600-4" manufactured by Mizutani Seisakusho Co., Ltd. Grindstone: High-speed grindstone #40 Grindstone rotation speed: 6000 rpm Work rotation direction: COUNTER Work rotation speed: 400 rpm Traverse speed: 250 mm / min

[0127] [2.3. Molding time] The total time required for curing the primer layer and the elastomer layer was measured.

[0128] [2.4. Bleed] When the OA roller was energized, it was visually evaluated whether low molecular weight substances bled. The energization conditions were 1000 V × 100 hours of energization.

[0129] [3. Results] The results are shown in Tables 2 to 4. In Tables 2 to 4, the history of each sample is also shown. From Tables 2 to 4, the following can be understood.

[0130] Regarding "adhesion", "○" indicates that the elastomer layer did not peel off during the grinding test, "×" indicates that the elastomer layer peeled off during the grinding test.

[0131] Regarding "molding time", "○" indicates that the total time required for curing is 5 minutes or less, "△" indicates that the total time required for curing is more than 5 minutes and 4 hours or less, "×" indicates that the total time required for curing is more than 4 hours and 8 hours or less, "××" indicates that the total time required for curing is more than 8 hours.

[0132] Regarding "bleed", "○" indicates that low molecular weight substances did not bleed when the OA roller was energized, "×" indicates that low molecular weight substances bled when the OA roller was energized.

[0133] (1) In Comparative Examples 1 and 2, the adhesion of the elastomer layer was good. However, in Comparative Examples 1 and 2, since no pigment was added to the base material layer, the volume resistivity of the base material increased. (2) In Comparative Examples 3 to 6, the elastomer layer peeled off during the grinding test. Also, in Comparative Examples 3 to 6, bleeding of low molecular weight substances was observed. This is considered to be because the raw material of the ultraviolet curable elastomer was directly applied to the surface of the base material layer containing carbon.

[0134] (3) In Comparative Example 7, the molding time exceeded 5 minutes. Also, in Comparative Example 7, bleeding of low molecular weight substances was observed. This is considered to be due to bleeding (oozing) of the oil contained as a plasticizer, or blooming (chemical attack) of hydrin·sulfur·halide. (4) In Comparative Examples 8 to 14, the molding time exceeded 5 minutes. This is considered to be because a solvent volatile type urethane primer was used as the primer layer. Also, in Comparative Example 14, bleeding of low molecular weight substances was observed. The bled low molecular weight substances are considered to be an ion conductive material added later to the solvent volatile type urethane primer.

[0135] (5) In all of Examples 1 to 9, the adhesiveness of the elastomer layer was good and the molding time was 5 minutes or less. Furthermore, in Examples 1 to 9, bleeding of low molecular weight substances was not observed.

[0136]

Table 2

[0137]

Table 3

[0138]

Table 4

[0139] As described above in detail for the embodiments of the present invention, the present invention is not limited to the above embodiments at all, and various modifications are possible without departing from the gist of the present invention.

Industrial Applicability

[0140] The roll for OA according to the present invention can be used for a transfer roller, a charging roller, a toner supply roller, a developing roller, a fixing roller, a paper feed roller, a paper discharge roller, etc.

Explanation of Signs

[0141] 10 Roll for OA 12 Shaft 14 Base material layer 16 Primer layer 18 Elastomer layer

Claims

1. obtained by reacting a polyol and a polyisocyanate to form an NCO-group-terminated urethane prepolymer and then sealing the NCO groups of the NCO-group-terminated urethane prepolymer with an ultraviolet-curable monoalcohol and a non-ultraviolet-curable monoalcohol, a urethane prepolymer satisfying the following formulas (1) to (4). 0.30 ≤ Y 1 / X ≤ 0.70...(1) 0.10 ≤ Y 2 / X ≤ 0.50...(2) 0.05 ≤ Y 3 / X ≤ 0.40 …(3) 1.00 ≤ (Y 1 + Y 2 + Y 3 ) / X ≤ 1.05... (4) However, X is the number of moles of NCO groups contained in the polyisocyanate, Y 1 is the number of moles of OH groups contained in the polyol, Y 2 is the number of moles of OH groups contained in the ultraviolet curable monool, Y 3 is the number of moles of OH groups contained in the non-UV curable monoalcohol.

2. The urethane prepolymer according to claim 1, wherein the non-ultraviolet-curable monoalcohol contains a conductive monoalcohol composed of an ionic compound.

3. a shaft, a base material layer formed on the outer peripheral surface of the shaft, a primer layer formed on the outer peripheral surface of the base material layer, and an elastomer layer formed on the outer peripheral surface of the primer layer are provided, the base material layer contains a foamed resin and a pigment that absorbs ultraviolet rays and is dispersed in the foamed resin, the primer layer contains a first ultraviolet-curable elastomer, the elastomer layer contains a second ultraviolet-curable elastomer, the first ultraviolet-curable elastomer contains an elastomer obtained by photopolymerizing a raw material containing the urethane prepolymer according to claim 1 roller for OA.

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