Paper feed roll

Abstract

To provide a paper feed roll allowing for realizing hardness decrease while suppressing bleed out of plasticizer.SOLUTION: A paper feed roll 10 comprises a shaft body 12 and an elastic-body layer 14 formed on an outer peripheral surface of the shaft body 12. The elastic-body layer 14 contains binder polymer consisting of polyether polyurethane containing polyether polyol and polycarbonate polyol as polyol components and plasticizer having an ester group, thus having JIS-A hardness of 25 degree or higher and 55 degree or lower.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a paper feed roll that is suitably used in electrophotographic devices such as copying machines, printers, and facsimiles that employ an electrophotographic system. [Background technology]

[0002] As a paper feed roll, one having an elastic layer made of an elastic material such as a crosslinked rubber on the outer circumferential surface of a shaft such as a core metal is known. For example, Patent Document 1 discloses a paper feed roll using polyether polyurethane as the elastic material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4356801 Summary of the Invention [Problem to be solved by the invention]

[0004] By making the elastic layer low hardness, the paper feed roll can expand the nip area with the paper and increase the friction coefficient to improve the paper conveying force. In order to make the elastic layer low hardness, it is effective to add a plasticizer to the elastic layer. However, in a paper feed roll using polyether polyurethane as the elastic material, the plasticizer added to the elastic layer is likely to bleed out, which may cause a problem of transfer to the paper.

[0005] The problem to be solved by the present invention is to provide a paper feed roll that can realize low hardness while suppressing the bleeding out of a plasticizer. [Means for solving the problem]

[0006] The paper feed roll of the present invention comprises a shaft body and an elastic layer formed on the outer peripheral surface of the shaft body, the elastic layer containing a binder polymer composed of polyether polyurethane containing polyether polyol and polycarbonate polyol as polyol components, and a plasticizer having an ester group, and has a JIS-A hardness of 25 degrees or more and 55 degrees or less.

[0007] The content of the polycarbonate polyol in the polyol component is preferably 3% by mass or more and 60% by mass or less. The plasticizer having an ester group preferably has a polyether chain. The content of the plasticizer having an ester group is preferably 30 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the binder polymer. The polyether polyol preferably has a polytetramethylene ether chain. The polycarbonate polyol preferably has a polyether chain. The polyether chain is preferably a polytetramethylene ether chain. The JIS-A hardness of the elastic layer is preferably 30 degrees or more and 40 degrees or less. Effect of the Invention

[0008] The paper feed roll according to the present invention comprises a shaft body and an elastic layer formed on the outer peripheral surface of the shaft body, and the elastic layer contains a binder polymer composed of polyether polyurethane containing polyether polyol and polycarbonate polyol as polyol components, and a plasticizer having an ester group, and has a JIS-A hardness of 25 degrees or more and 55 degrees or less, thereby making it possible to achieve a low hardness while suppressing bleed-out of the plasticizer.

[0009] When the content of the polycarbonate polyol in the polyol component is 3% by mass or more and 60% by mass or less, low hardness can be achieved while effectively suppressing bleeding out of the plasticizer.

[0010] When the plasticizer having an ester group has a polyether chain, the compatibility with the polyol component constituting the binder polymer is improved, and bleeding out of the plasticizer is further suppressed.

[0011] When the content of the plasticizer having an ester group is 30 parts by mass or more and 60 parts by mass or less relative to 100 parts by mass of the binder polymer, the bleed-out of the plasticizer is suppressed despite the relatively large content of the plasticizer, and since the content of the plasticizer is large, the effect of reducing hardness is excellent.

[0012] When the polyether polyol has a polytetramethylene ether chain, the molecular skeleton has excellent toughness and good abrasion resistance.

[0013] When the polycarbonate polyol has a polyether chain, the compatibility with a plasticizer having a polyether chain and an ester group is improved, and the bleeding out of the plasticizer is further suppressed. In this case, when the polyether chain is a polytetramethylene ether chain, the molecular skeleton has excellent toughness and good abrasion resistance.

[0014] When the JIS-A hardness of the elastic layer is 30 degrees or more and 40 degrees or less, a low hardness can be achieved while effectively suppressing the bleeding out of the plasticizer. [Brief description of the drawings]

[0015] [Figure 1] 1A is a schematic diagram showing the appearance of a paper feed roll according to one embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line AA thereof. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The paper feed roll according to the present invention will be described in detail below. Fig. 1 is a schematic external view (a) of the paper feed roll according to one embodiment of the present invention, and a cross-sectional view (b) taken along line AA thereof.

[0017] The paper feed roll 10 according to one embodiment of the present invention includes a shaft body 12 and an elastic layer 14 formed on the outer peripheral surface of the shaft body 12. The elastic layer 14 is a layer (base layer) that serves as the base of the paper feed roll 10. The elastic layer 14 is a layer that appears on the surface of the paper feed roll 10.

[0018] The shaft body 12 may be a solid body or a hollow body (cylinder) made of metal or resin. Metal materials include iron, stainless steel, and aluminum. The elastic layer 14 may be bonded to the shaft body 12 via an adhesive layer (primer layer). The adhesive, primer, and the like may be made conductive as necessary.

[0019] The elastic layer 14 contains a binder polymer composed of polyether polyurethane containing polyether polyol and polycarbonate polyol as polyol components, and a plasticizer having an ester group. The elastic layer 14 contains polyether polyol as a polyol component, so that mechanical properties are ensured and the elastic layer 14 has excellent abrasion resistance. Note that the polyether polyol as a polyol component does not include polycarbonate polyol as a polyol component having a polyether chain (polycarbonate polyol having a polyether chain).

[0020] The polyether polyurethane binder polymer is made of a cured product of a urethane composition. The urethane composition contains a polyol component and an isocyanate component.

[0021] Polyether polyols have two or more ether bonds and two or more hydroxyl groups in the molecule. Suitable examples of polyether polyols include those obtained by ring-opening polymerization or copolymerization of cyclic ethers. Examples of cyclic ethers include ethylene oxide, propylene oxide, trimethylene oxide, butylene oxide, α-methyltrimethylene oxide, 3,3'-dimethyltrimethylene oxide, tetrahydrofuran, dioxane, and dioxamine. Specific examples of polyether polyols include polytetramethylene ether glycol (PTMG), polypropylene glycol (PPG), and polyethylene glycol (PEG).

[0022] The polyether polyol is preferably one having a polytetramethylene chain, from the viewpoint of excellent toughness of the molecular skeleton, good abrasion resistance, etc. Examples of polyether polyols having a polytetramethylene chain include polytetramethylene ether glycol (PTMG).

[0023] The polyether polyol preferably has a number average molecular weight (Mn) of 1000 to 3500. More preferably, the number average molecular weight (Mn) is 1500 to 2500. When the number average molecular weight (Mn) of the polyether polyol is 1000 or more, the physical properties of the polyurethane can be ensured. When the number average molecular weight (Mn) of the polyether polyol is 3500 or less, the viscosity increase of the urethane prepolymer can be suppressed, and the moldability can be improved. The number average molecular weight is the molecular weight converted into standard polystyrene by gel permeation chromatography (GPC).

[0024] In the polyol component, the content of polyether polyol is preferably 40% by mass or more and 97% by mass or less. When the content of polyether polyol is 40% by mass or more, mechanical properties are ensured and the abrasion resistance is excellent. From the above viewpoint, the content of polyether polyol is more preferably 50% by mass or more, and even more preferably 60% by mass or more. On the other hand, when the content of polyether polyol is 97% by mass or less, the effect of suppressing the bleeding out of the plasticizer is excellent. From the above viewpoint, the content of polyether polyol is more preferably 95% by mass or less, and even more preferably 93% by mass or less.

[0025] Polycarbonate polyol has two or more carbonate bonds and two or more hydroxyl groups in a molecule. As the polycarbonate polyol, polycarbonate diol is preferable from the viewpoint of low hardness, elastic recovery, etc. As the polycarbonate polyol, one obtained by a condensation reaction of a polyol and a carbonate compound is preferable. Examples of the carbonate compound include dialkyl carbonate, diaryl carbonate, and alkylene carbonate. The polyol constituting the polycarbonate polyol may be a non-polymerizable (low molecular weight) polyol such as hexanediol and butanediol, or a polymerizable (high molecular weight) polyol such as polyether polyol. Examples of the polyol constituting the polycarbonate polyol include diols such as hexanediol and butanediol, triols such as 2,4-butanetriol, polytetramethylene ether glycol (PTMG), polypropylene glycol (PPG), and polyethylene glycol (PEG).

[0026] The polycarbonate polyol preferably has a number average molecular weight (Mn) of 1000 to 3500. More preferably, the number average molecular weight (Mn) is 1500 to 2500. When the number average molecular weight (Mn) of the polyether polyol is 1000 or more, the physical properties of the polyurethane can be ensured. Also, when the number average molecular weight (Mn) of the polyether polyol is 3500 or less, the viscosity increase of the urethane prepolymer can be suppressed, and the moldability can be improved. The number average molecular weight is the molecular weight converted into standard polystyrene by gel permeation chromatography (GPC).

[0027] As the polycarbonate polyol, those having a polyether chain are preferred from the viewpoints of improving compatibility with a plasticizer having a polyether chain and an ester group, and further suppressing the bleeding out of the plasticizer, etc. Furthermore, among the polyether chains, polytetramethylene ether chains are preferred from the viewpoints of excellent toughness of the molecular skeleton and good abrasion resistance, etc.

[0028] Among the polyol components, the content of polycarbonate polyol is preferably 3% by mass or more and 60% by mass or less. When the content of polycarbonate polyol is 3% by mass or more, low hardness can be achieved while effectively suppressing the bleed-out of the plasticizer. From the above viewpoint, the content of polycarbonate polyol is more preferably 5% by mass or more, and even more preferably 7% by mass or more. On the other hand, when the content of polycarbonate polyol is 60% by mass or less, the resilience modulus preferred for a paper feed roll decreases. From the above viewpoint, the content of polycarbonate polyol is more preferably 50% by mass or less, and even more preferably 40% by mass or less.

[0029] As the polycarbonate polyol, one having a structure represented by the following chemical formula (1) is suitable. [ka]

[0030] In formula (1), l and m each represent the number of repeating units consisting of an integer of 1 or more, and R1 represents an alkylene group. In formula (1), l is 2 or more, and is a polycarbonate polyol having a polyether chain. l is preferably 2 or more, and more preferably 3 or more. R1 preferably has 2 to 4 carbon atoms, and more preferably has 4 carbon atoms.

[0031] Examples of isocyanates include 4,4'-diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), trimethylhexamethylene diisocyanate (TMHDI), tolylene diisocyanate (TDI), carbodiimide-modified MDI, polymethylene phenyl isocyanate (PAPI), orthotoluidine diisocyanate (TODI), naphthylene diisocyanate (NDI), xylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), paraphenylene diisocyanate (PDI), lysine diisocyanate methyl ester (LDI), dimethyl diisocyanate (DDI), etc. These may be used alone as the isocyanate component, or two or more may be used in combination. Among these, 4,4'-diphenylmethane diisocyanate (MDI) is particularly preferred from the standpoints of improved abrasion resistance, ease of handling, availability, cost, and the like.

[0032] The isocyanate may be an NCO-terminated urethane prepolymer obtained by reacting an isocyanate such as the above-mentioned MDI with a polyol. The urethane prepolymer used as the isocyanate is preferably NCO% in the range of 5 to 30 mass% in order to have an NCO terminal. The NCO% is calculated by the following formula.

[0033]

number

[0034] The amount of isocyanate blended is preferably set so that the NCO index (isocyanate index) is 110 or more from the viewpoints of easily improving abrasion resistance, easily securing strength, and being less prone to settling. The NCO index is more preferably 115 or more, even more preferably 120 or more, 125 or more, or 130 or more. On the other hand, from the viewpoints of not being too hard and being easy to mold, it is preferable to set the NCO index to 160 or less. The NCO index is more preferably 155 or less, even more preferably 150 or less, or 145 or less. The NCO index is calculated as the equivalent of an isocyanate group relative to the total equivalent of 100 of active hydrogen groups (hydroxyl groups, amino groups, etc.) that react with an isocyanate group.

[0035] The plasticizer having an ester group is preferably a plasticizer that can be blended with polyurethane, and examples of the plasticizer having an ester group include polyether ester, adipic acid ether ester, adipic acid polyester, adipic acid ester, sebacic acid ester, benzoic acid ester, azelaic acid ester, trimellitic acid ester, and phthalic acid ester.

[0036] As the plasticizer having an ester group, one having a polyether chain is preferable from the viewpoint of improving compatibility with the polyol component constituting the binder polymer and further suppressing the bleeding out of the plasticizer. Examples of the plasticizer having a polyether chain and an ester group include polyether ester, adipic acid ether ester, and benzoic acid ester. Among these, polyether ester is particularly preferable.

[0037] As the polyether ester plasticizer, one having a structure represented by the following chemical formula (2) is suitable. [ka]

[0038] In formula (2), n is the number of repeating units consisting of an integer of 2 or more, R2 is an alkyl group or an aryl group, and R3 is an alkylene group. R2 preferably has 4 or more carbon atoms. R3 preferably has 2 to 4 carbon atoms, and particularly preferably has 4 carbon atoms.

[0039] The polyether ester plasticizer preferably has a number average molecular weight of 400 to 2,000 from the viewpoint of moldability.

[0040] Examples of polyether ester plasticizers include ADEKA's Adekaizer RS-700, RS-735, RS-966, and RS-1000. Examples of adipic acid ether ester plasticizers include ADEKA's Adekaizer RS-107. Examples of adipic acid polyester plasticizers include ADEKA's Adekaizer PN-150, PN-170, P-200, and PN-350.

[0041] Examples of adipic acid esters include dioctyl adipate (DOA) and diisononyl adipate (DINA). Examples of sebacic acid esters include dioctyl sebacate. Examples of benzoic acid esters include ethylene glycol dibenzoate, diethylene glycol dibenzoate, propylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol dibenzoate, 1,4-cyclohexene dimethanol dibenzoate, and polyethylene glycol dibenzoate. Examples of azelaic acid esters include dioctyl azelate.

[0042] Examples of trimellitic acid esters include 2-ethylhexyl trimellitate, isononyl trimellitate, etc. Examples of phthalic acid esters include dioctyl phthalate (DOP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), dibutyl phthalate (DBP), etc.

[0043] The content of the plasticizer having an ester group is preferably 30 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the binder polymer. When the content is 30 parts by mass or more, the elastic layer can have an even lower hardness. From this viewpoint, the content is more preferably 35 parts by mass or more, and even more preferably 40 parts by mass or more. Also, when the content is 60 parts by mass or less, bleeding out of the plasticizer is easily suppressed. From this viewpoint, the content is more preferably 55 parts by mass or less, and even more preferably 50 parts by mass or less.

[0044] The urethane composition may contain a chain extender, a crosslinking agent, a catalyst, etc. Furthermore, the urethane composition may contain an ion conductive agent, a foaming agent, a surfactant, a flame retardant, a colorant, a filler, a stabilizer, a release agent, etc., as necessary.

[0045] The chain extender is a bifunctional compound such as a diol or diamine that can react with polyurethane. A number average molecular weight of 300 or less is preferable. Examples of the chain extender include diols such as 1,4-butanediol (1,4-BD), ethylene glycol (EG), 1,6-hexanediol (1,6-HD), diethylene glycol (DEG), propylene glycol (PG), dipropylene glycol (DPG), 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, xylene glycol, and triethylene glycol, and aromatic diamines such as 2,2',3,3'-tetrachloro-4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diphenylmethane, trimethylene-bis(4-aminobenzoate), and 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane. These may be used alone as a chain extender, or two or more may be used in combination. Among these, 1,4-butanediol (1,4-BD), ethylene glycol (EG), 1,6-hexanediol (1,6-HD), etc. are preferred from the viewpoints of ensuring physical properties and easily achieving improved moldability.

[0046] The crosslinking agent is a trifunctional or higher compound such as triol or triamine that can react with polyurethane. A number average molecular weight of 300 or less is preferable. Examples of the crosslinking agent include trimethylolpropane (TMP), glycerin, pentaerythritol, sorbitol, and 1,2,6-hexanetriol. These may be used alone as the crosslinking agent, or two or more may be used in combination. Among these, trimethylolpropane (TMP) is preferable from the viewpoint of ensuring physical properties and easily improving moldability.

[0047] The content of the chain extender in the urethane composition is not particularly limited as long as it is within a range that favorably promotes the urethane reaction. For example, it is preferably within a range of 1 to 5 parts by mass per 100 parts by mass of polyol. The content of the crosslinking agent in the urethane composition is not particularly limited as long as it is within a range that favorably promotes the urethane reaction. For example, it is preferably within a range of 1 to 5 parts by mass per 100 parts by mass of polyol.

[0048] The catalyst is not particularly limited, and examples thereof include amine compounds such as tertiary amines, organometallic compounds such as organotin compounds, etc. Examples of tertiary amines include trialkylamines such as triethylamine, tetraalkyldiamines such as N,N,N',N'-tetramethyl-1,3-butanediamine, aminoalcohols such as dimethylethanolamine, esteramines such as ethoxylated amines, ethoxylated diamines, bis(diethylethanolamine)adipate, triethylenediamine (TEDA), cyclohexylamine derivatives such as N,N-dimethylcyclohexylamine, morpholine derivatives such as N-methylmorpholine, N-(2-hydroxypropyl)-dimethylmorpholine, piperazine derivatives such as N,N'-diethyl-2-methylpiperazine, N,N'-bis-(2-hydroxypropyl)-2-methylpiperazine, etc. Examples of the organic tin compound include dialkyl tin compounds such as dibutyltin dilaurate and dibutyltin di(2-ethylhexoate), stannous 2-ethylcaproate, and stannous oleate. These may be used alone or in combination as a catalyst. Among these, triethylenediamine (TEDA) is preferably used from the viewpoints of resistance to hydrolysis and less contamination due to bleeding.

[0049] The content of the catalyst in the urethane composition is not particularly limited as long as it is within a range that favorably promotes the urethane reaction. For example, the content is preferably within a range of 0.01 to 5 parts by mass, and more preferably within a range of 0.1 to 3 parts by mass, relative to 100 parts by mass of the polyol.

[0050] The paper feed roll 10 can be produced by casting a urethane composition into a roll molding die in which a core metal that will become the shaft body 12 is set, and then reacting and curing the composition. Cast molding can be carried out in accordance with the prepolymer method, semi-one-shot method, or one-shot method. The urethane composition can be prepared by reacting a polyol component and an isocyanate component in advance to form an NCO-terminated urethane prepolymer, and then adding the polyol component, a chain extender, a crosslinking agent, a catalyst, etc.

[0051] The elastic layer 14 contains a plasticizer, and thus has a low hardness. Specifically, the elastic layer 14 has a JIS-A hardness of 25 degrees or more and 55 degrees or less. The JIS-A hardness of the elastic layer 14 is more preferably 30 degrees or more and 40 degrees or less. By making the elastic layer 14 have a lower hardness, the nip area with the paper can be expanded and the friction coefficient can be increased, thereby improving the paper conveying force.

[0052] The thickness of the elastic layer 14 is not particularly limited, but may be, for example, 1 to 10 mm.

[0053] According to the paper feed roll 10 having the above-mentioned configuration, the elastic layer 14 contains a binder polymer composed of polyether polyurethane containing polyether polyol and polycarbonate polyol as polyol components, and a plasticizer having an ester group, and has a JIS-A hardness of 25 degrees or more and 55 degrees or less, so that it is possible to achieve a low hardness while suppressing bleeding out of the plasticizer.

[0054] When the content of polycarbonate polyol in the polyol component is 3% by mass or more and 60% by mass or less, low hardness can be achieved while effectively suppressing the bleeding out of the plasticizer. When the plasticizer having an ester group has a polyether chain, the compatibility with the polyol component constituting the binder polymer is improved, and the bleeding out of the plasticizer is further suppressed. When the content of the plasticizer having an ester group is 30 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the binder polymer, the bleeding out of the plasticizer is suppressed despite the relatively large content of the plasticizer. In addition, since the content of the plasticizer is large, the effect of reducing hardness is excellent. When the polyether polyol has a polytetramethylene ether chain, the toughness of the molecular skeleton is excellent and the wear resistance is good. Then, the compatibility with the plasticizer having a polyether chain and an ester group is improved, and the bleeding out of the plasticizer is further suppressed. In this case, if the polyether chain is a polytetramethylene ether chain, the molecular skeleton has excellent toughness and good abrasion resistance.

[0055] A particularly suitable combination for the urethane composition constituting the binder polymer of the elastic layer 14 is one that contains a polyether polyol and a polycarbonate polyol having a polyether chain as the polyol component, and a plasticizer having a polyether chain and an ester group as the plasticizer.

[0056] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0057] For example, in the above embodiment, the paper feed roll 10 has a single-layer structure consisting of only the elastic layer 14, but if necessary, a surface layer may be formed on the outer peripheral surface of the elastic layer 14. The outer peripheral surface of the elastic layer 14 may be a flat surface or may have an uneven shape such as a grained shape. EXAMPLES

[0058] The present invention will be described in detail below using examples and comparative examples.

[0059] Example 1 <Preparation of urethane composition> Polytetramethylene ether glycol (PTMG) 65 parts by mass, polypropylene glycol (PPG) 25 parts by mass, polycarbonate diol having a polyether chain (PEPCD <1> After 10 parts by mass of the mixture was degassed and dehydrated under vacuum at 80°C for 1 hour, 25.5 parts by mass of isocyanate (MDI) was added and reacted at 80°C for 3 hours in a nitrogen atmosphere to obtain a urethane prepolymer. <1> The prepared urethane prepolymer was then <1> After vacuum degassing at 90°C for 30 minutes, the urethane prepolymer <1> Polyether ester (plasticizer) per 100 parts by weight <1> An uncrosslinked urethane composition was prepared by mixing 10 parts by mass of a copolymer of 1,4-butanediol (1,4-BD) with 3.0 parts by mass of a chain extender (1,4-butanediol (1,4-BD)), 2.0 parts by mass of a crosslinking agent (trimethylolpropane (TMP)), and 0.01 parts by mass of a catalyst (triethylenediamine (TEDA)) under reduced pressure and stirring for 2 minutes.

[0060] <Preparation of paper feed roll> A roll molding die in which a core metal (diameter 8 mm, made of SUS304) that would become the shaft was set was prepared and heated to 140°C. Next, the prepared urethane composition was poured into the die and subjected to a curing reaction at 140°C for 60 minutes to obtain a cured product. The obtained cured product was demolded and subjected to secondary curing at 110°C for 12 hours, and then the surface was polished to produce a paper feed roll in which an elastic layer (thickness 6 mm) was formed on the outer peripheral surface of the shaft.

[0061] (Examples 2 to 6) A urethane composition was prepared in the same manner as in Example 1 using the composition shown in Table 3. A paper feed roll was also produced in the same manner as in Example 1.

[0062] (Examples 7 to 16) Urethane prepolymer with the composition shown in Table 1 <1> Similarly, each urethane prepolymer <2> ~ <11> Using each of the prepared urethane prepolymers, urethane compositions were prepared in the same manner as in Example 1 according to the compositions shown in Table 3. Also, a paper feed roll was produced in the same manner as in Example 1.

[0063] (Comparative Examples 1 to 10) Urethane prepolymer with the composition shown in Table 2 <1> Each of the urethane prepolymers A to F was prepared in the same manner as in Example 1. Using each of the prepared urethane prepolymers, a urethane composition was prepared in the same manner as in Example 1 according to the composition shown in Table 4. Also, a paper feed roll was produced in the same manner as in Example 1.

[0064] The materials used are as follows: (Polyether polyol) ·PTMG: “PTG2000” manufactured by Hodogaya Chemical, Mn=2000 PPG: AGC "Exenol 2020", Mn=3000 (Polycarbonate polyol) PEPCD <1> :Mitsubishi Chemical "NT2002", Mn=2000 PEPCD <2> :Mitsubishi Chemical "NT2006", Mn=2000 PCD: Ube Industries "PH-200", Mn=2000 (Plasticizers with ester groups) Plasticizers <1> (Polyetherester plasticizer): ADEKA "Adeka Cizer RS-1000" Plasticizers <2> (Benzoic acid ester plasticizer): DIC "Monocizer PB10" Plasticizers <3> (Adipic acid ether ester plasticizer): ADEKA "Adeka Cizer RS-107"

[0065] The JIS-A hardness of the elastic layer of the fabricated paper feed roll was measured. Also, it was investigated whether the plasticizer of the fabricated paper feed roll bleeds out or not.

[0066] (JIS-A hardness) In accordance with JIS K 7321, the hardness of the outer peripheral surface of the elastic layer was measured with a type A durometer under a load of 9.8 N.

[0067] (bleed out) The paper feed roll was pressed against the paper (Red River) with a load of 150g and left in an environment of 32.5℃ x 85% RH for 48 hours. After that, the paper feed roll was removed from the paper and the marks transferred to the paper were evaluated. If there was no mark or the mark width was less than 1mm, it was evaluated as "Good", if the mark width was 1mm to less than 2mm, it was evaluated as "Good", and if the mark width was 2mm or more, it was evaluated as "Poor".

[0068] [Table 1]

[0069] [Table 2]

[0070] [Table 3]

[0071] [Table 4]

[0072] In Comparative Example 1, the elastic layer does not contain a plasticizer, and therefore the JIS-A hardness is as hard as 60. In Comparative Examples 2 to 10, the elastic layer contains a plasticizer and has a low hardness, but since the elastic layer is composed of a polyether polyurethane and a plasticizer having an ester group, the plasticizer bleeds out.

[0073] On the other hand, in the examples, the elastic layer is composed of a polyether-based polyurethane containing polyether polyol and polycarbonate polyol as polyol components, and a plasticizer having an ester group, so that the bleed-out of the plasticizer is suppressed while maintaining a low hardness. Also, a comparison of examples 2, 5, and 6 shows that the polyether ester-based plasticizer is particularly good in that it reduces the hardness more when the same amount is added.

[0074] Although the embodiments and examples of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments and examples, and various modifications are possible without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0075] 10 Paper feed roll 12 Axial body 14 Elastic layer

Claims

1. A shaft body and an elastic layer formed on an outer circumferential surface of the shaft body, The elastic layer comprises a binder polymer composed of polyether polyurethane containing polyether polyol and polycarbonate polyol as polyol components, and a plasticizer having an ester group, and has a JIS-A hardness of 25 degrees or more and 55 degrees or less.

2. The paper feed roll according to claim 1 , wherein the content of the polycarbonate polyol in the polyol component is 3% by mass or more and 60% by mass or less.

3. The paper feed roll according to claim 1 or 2, wherein the plasticizer having an ester group has a polyether chain.

4. The paper feed roll according to claim 1 , wherein the content of the plasticizer having an ester group is 30 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the binder polymer.

5. The paper feed roll according to claim 1 , wherein the polyether polyol has a polytetramethylene ether chain.

6. The paper feed roll according to claim 1 , wherein the polycarbonate polyol has a polyether chain.

7. 7. The paper feed roll of claim 6, wherein the polyether chains are polytetramethylene ether chains.

8. The paper feed roll according to any one of claims 1 to 7, wherein the elastic layer has a JIS-A hardness of 30 degrees or more and 40 degrees or less.

Images