JP2007002015A - Rubber-crosslinked material for paper delivery roll and paper-delivery roll using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber-crosslinked material for a paper delivery roll, having a good abrasion resistance and capable of reducing the decreasing ratio of its frictional coefficient μ and the shrinking amount of its roll outer diameter on transferring it from a normal temperature environment to a low temperature environment, and the rubber roll for paper delivery by using the same. <P>SOLUTION: This rubber-crosslinked material for the paper delivery roll, containing at least a polymer component is provided with that the polymer component contains an ethylene, propylene-diene copolymer, and the rubber-crosslinked material for the paper delivery roll satisfies the following formula (1) and also the following formula (2) and/or (3) under a prescribed viscoelasticity-measuring condition. tanδ(22°C)-(0.0031×E1(22°C)+0.0503)≤0---(1) A(E1)-(-0.0414×E1(22°C)+0.0750)≥0--------(2) B(E1)-(-0.0066×E1(22°C)+0.0200)≥0--------(3). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a rubber cross-linked product for paper feed rolls having good wear resistance and capable of reducing the reduction rate of the friction coefficient μ and the shrinkage amount of the outer diameter of the roll during transition from a normal temperature environment to a low temperature environment. And a paper feed roll using the same.

  Paper feed rolls used in OA equipment such as electrostatic copying machines, laser printers, facsimiles, and automatic deposit payment machines have high wear resistance and friction coefficient, and the wear resistance and friction coefficient are high. It is required to have excellent retention. Further, since ozone is generated during image formation by an electrostatic copying machine, a laser printer, a facsimile machine, etc., the rubber composition used for the paper feed roll is also required to be resistant to ozone deterioration. Therefore, as a rubber composition used for the paper feeding roll, there is a conventional rubber composition mainly composed of an ethylene propylene-diene copolymer (EPDM) which has excellent wear resistance and ozone resistance and is inexpensive. Has been used.

  However, in order to maintain paper feeding characteristics that are stable over a wide temperature range for a long period of time, it is necessary to further improve the wear resistance and the friction coefficient. In the paper feed roll, in general, the initial friction coefficient is larger and better as the hardness is smaller, while the wear resistance tends to be better as the hardness is larger and tan δ (loss tangent) is smaller. Therefore, a high coefficient of friction and high wear resistance are contradictory properties, and various studies have been made to achieve both properties.

  Specifically, for example, a method of increasing the crosslinking density of the rubber composition by increasing the amount of the crosslinking agent in the rubber composition for paper feed rolls can be mentioned. However, this method has a problem that a bloom of the crosslinking agent tends to occur. On the other hand, there is also a method of increasing the ethylene content of the ethylene propylene-diene copolymer or increasing the molecular weight of the ethylene propylene-diene copolymer using a rubber composition mainly composed of an ethylene propylene-diene copolymer. Can be mentioned. However, when the ethylene content of the ethylene propylene-diene copolymer is increased, there is a problem that the initial friction coefficient decreases due to an increase in rubber hardness, and the friction coefficient decreases due to an increase in rubber hardness under low temperature conditions, There are also problems such as an increase in compression set under low temperature conditions and shrinkage of the outer diameter of the roll under low temperature conditions. Further, when the molecular weight of the ethylene propylene-diene copolymer is increased, there is a problem that workability during extrusion and pressing is lowered.

  Patent Document 1 discloses zinc oxide having a mixing weight ratio of 1: 2 to 2: 1 with respect to 100 parts by weight of an ethylene propylene-diene copolymer having a Mooney viscosity ML1 + 4 (100 ° C.) ≧ 70 and an ethylene content ≧ 60 wt%. A crosslinkable rubber composition characterized by blending methacrylic acid in a total amount of 20 to 40 parts by weight, reinforcing furnace carbon black, and organic peroxide has been proposed. However, there is a problem that it is difficult to obtain sufficient wear resistance with peroxide crosslinking.

  Patent Document 2 discloses a rubber composition based on an ethylene propylene-diene copolymer having an iodine value of 20 or more, an iodine adsorption amount of 25% to 50% by weight of 40 mg / g or more, and DBP. A rubber composition comprising carbon black having an oil absorption of 100 ml / 100 g or more, 5 wt% to 20 wt% paraffinic process oil, and an organic peroxide as a crosslinking agent. Proposed. In the rubber composition, by setting the iodine value to 20 or more, the crosslink density is increased and the compression set is reduced, but the retention of the coefficient of friction during paper passing tends to be lowered. In addition, there is a problem that it is difficult to obtain sufficient wear resistance with peroxide crosslinking.

  In Patent Document 3, calcium silicate is used in an amount of 5 to 30% by weight with respect to 100 parts by weight of an ethylene-propylene-diene terpolymer rubber having an ethylene content of 55 to 95% by weight and a diene content of 10 to 20% by weight. A rubber composition having a Mooney viscosity ML1 + 4 (100 ° C.) of 50 or more has been proposed. In the rubber composition for rolls, the compression set can be reduced by adjusting the diene content within a predetermined range, but the retention of the coefficient of friction during paper feeding tends to decrease.

  In Patent Document 4, an EP (ethylene propylene) rubber having an average molecular weight of 300,000 or more and an ethylene content of 60 to 80% by weight as a main component is used, and a softener is added to 100 parts by weight of the EP rubber. There has been proposed a rubber composition for paper feed rollers, which is blended within a range of ˜190 parts by weight and blended within a range in which the amount of elemental sulfur is suppressed to 0.2% by weight or less. Although the abrasion resistance can be improved by setting the average molecular weight of the EP rubber to 300,000 or more, the workability is poor because the lower limit of the molecular weight specified is large, and it is necessary to add a large amount of softener. is there. However, since the wear resistance deteriorates as the blending amount of the softening agent is increased, this method cannot obtain a sufficient effect of improving the wear resistance.

Patent Document 5 discloses a paper sheet conveying member having a dynamic elastic modulus E ′ of 0.9 to 1.9 MPa under the conditions of a temperature of 25 ° C., a frequency of 15 Hz, and an extension ratio of 15 ± 2%. Rubber materials have been proposed. By setting the dynamic elastic modulus within a predetermined range, the rubber material for the paper sheet conveying member has a restoring force due to deformation of the rubber even when the adhesion force of the rubber surface is reduced due to adhesion of paper dust. The aim is to maintain the conveying force. However, since the restoring force depends on the rebound resilience or tan δ (loss tangent), there is a problem that a sufficient effect cannot be obtained in improving the retention of the friction coefficient only by controlling the dynamic elastic modulus of the rubber.
JP 11-199725 A JP 2000-248133 A Japanese Patent Application Laid-Open No. 10-114845 Japanese Patent Application Laid-Open No. 7-242799 JP 2001-171851 A

  The present invention solves the above problems, has good wear resistance and retention of the friction coefficient at the time of passing the paper, and the reduction rate of the friction coefficient μ and the outer diameter of the roll during the transition from the normal temperature environment to the low temperature environment. An object is to provide a paper feed roll having a small shrinkage.

The present invention is a rubber cross-linked product for paper feed rolls containing at least a polymer component, wherein the polymer component contains an ethylene propylene-diene copolymer, and the measured temperature in the rubber cross-linked product for paper feed rolls is: Dynamic elasticity measured under viscoelasticity measurement conditions of 84 ° C. to 52 ° C., heating rate: 2 ° C./min, measurement temperature interval: 4 ° C., measurement frequency f: 10 Hz, initial strain: 4 mm, amplitude: 0.1 mm The values of the rate E1 [MPa] and the loss tangent tan δ are expressed by the following formula (1),
tan δ (22 ° C.) − (0.0031 × E1 (22 ° C.) + 0.0503) ≦ 0 (1)
(In formula (1), E1 (22 ° C.) and tan δ (22 ° C.) are values of dynamic elastic modulus E1 [MPa] and loss tangent tan δ at 22 ° C., respectively.)
And the following formula (2) and / or formula (3),
A (E1) − (− 0.0414 × E1 (22 ° C.) + 0.0750) ≧ 0 (2)
(In Formula (2), A (E1) is an approximate straight line obtained by linear approximation using the method of least squares from the relationship between the measured temperature and the measured temperature of the dynamic elastic modulus E1 at 10 to 30 ° C.) And the slope of the approximate straight line where the correlation coefficient R ² ≧ 0.8 (unit: MPa / ° C.)),
B (E1) − (− 0.0066 × E1 (22 ° C.) + 0.0200) ≧ 0 (3)
(In Formula (3), B (E1) is an approximate straight line obtained by linear approximation using the method of least squares from the relationship between the measured temperature and the measured temperature of the dynamic elastic modulus E1 at 20 to 40 ° C. And the slope of the approximate straight line where the correlation coefficient R ² ≧ 0.8 (unit: MPa / ° C.)),
It is related with the rubber crosslinked material for paper feed rolls which satisfy | fills.

In the present invention, the rubber cross-linked product for paper feed roll is represented by the following formula (4),
T _max − (− 32 ° C.) ≦ 0 (4)
(In formula (4), T _max is the temperature (unit: ° C.) at which tan δ (loss tangent) takes the maximum value in the above viscoelasticity measurement conditions)
It is preferable to satisfy.

  In the rubber cross-linked product for paper feed rolls of the present invention, the ethylene unit content in the ethylene propylene-diene copolymer is preferably 50% by mass or more and 63% by mass or less.

  Moreover, it is also preferable that content of the ethylene propylene-diene copolymer in a polymer component is 50 mass% or more.

  Furthermore, the content of the ethylene propylene-diene copolymer in the polymer component is 90% by mass or more, and the content of the ethylene unit in the ethylene propylene-diene copolymer is 50% by mass or more and 62% by mass or less. It is also preferable.

  Furthermore, the content of the ethylene propylene-diene copolymer in the polymer component is 90% by mass or more, and the content of the ethylene unit in the ethylene propylene-diene copolymer is 50% by mass or more and 61% by mass or less. It is also preferable.

  In this invention, it is preferable that the compounding quantity of the softener with respect to 100 mass parts of a polymer component shall be 15 mass parts or less.

The rubber cross-linked product for paper feed rolls of the present invention is preferably formed by cross-linking with sulfur.
The present invention also relates to a paper feed roll using the rubber cross-linked product for paper feed roll as a rubber layer.

  According to the present invention, while having good wear resistance and retention of the friction coefficient at the time of paper passing, the reduction rate of the friction coefficient μ and the shrinkage amount of the outer diameter of the roll at the time of transition from the normal temperature environment to the low temperature environment. It becomes possible to obtain a small rubber cross-linked product for paper feed rolls and a paper feed roll using the same.

The present invention relates to a rubber cross-linked product for a paper feed roll having a polymer component containing an ethylene propylene-diene copolymer and having a predetermined viscoelastic property described later, and a paper feed roll using the same. The paper feed roll of the present invention is formed by inserting a shaft member made of, for example, metal or resin into a cylindrical rubber layer, and the rubber cross-linked product for the paper feed roll forming the rubber layer has a measurement temperature of − 84 ° C. to 52 ° C., temperature increase rate: 2 ° C./min, measurement temperature interval: 4 ° C., measurement frequency f: 10 Hz, initial strain: 4 mm, amplitude: 0.1 mm, sample size: width 4 mm × length 40 mm × thickness In the viscoelasticity measurement condition of 2 mm, the following formula (1),
tan δ (22 ° C.) − (0.0031 × E1 (22 ° C.) + 0.0503) ≦ 0 (1)
(In formula (1), E1 (22 ° C.) and tan δ (22 ° C.) are values of dynamic elastic modulus E1 [MPa] and loss tangent tan δ at 22 ° C., respectively)
And the following formula (2) and / or formula (3),
A (E1) − (− 0.0414 × E1 (22 ° C.) + 0.0750) ≧ 0 (2)
(In Formula (2), A (E1) is an approximate straight line obtained by linear approximation using the method of least squares from the relationship between the measured temperature and the measured temperature of the dynamic elastic modulus E1 at 10 to 30 ° C.) And the slope of the approximate straight line where the correlation coefficient R ² ≧ 0.8 (unit: MPa / ° C.)),
B (E1) − (− 0.0066 × E1 (22 ° C.) + 0.0200) ≧ 0 (3)
(In Formula (3), B (E1) is an approximate straight line obtained by linear approximation using the method of least squares from the relationship between the measured temperature and the measured temperature of the dynamic elastic modulus E1 at 20 to 40 ° C. And the slope of the approximate straight line where the correlation coefficient R ² ≧ 0.8 (unit: MPa / ° C.)),
Meet.

FIG. 1 is a diagram showing the relationship between E1 (22 ° C.) and tan δ (22 ° C.). The straight line in Fig. 1 is the following function:
tan δ (22 ° C.) = 0.0031 × E1 (22 ° C.) + 0.0503
Is shown. That is, the rubber cross-linked product for paper feed rolls used in the present invention has viscoelastic properties belonging to the straight line in FIG. 1 or a region where tan δ (22 ° C.) is smaller than the straight line.

  In general, in the paper feed roll, in order to sufficiently obtain the required performance such as wear resistance, the dynamic elasticity of the rubber cross-linked product in the rubber layer depends on the site in the paper feed device in which the paper feed roll is used. Set the rate appropriately within the appropriate range. As a guideline for adjusting the dynamic elastic modulus in this case, for example, the dynamic elastic modulus E1 (22 ° C.) at 22 ° C. is set to a set value (unit: MPa) ± 2 MPa of E1 (22 ° C.) considered to be optimum. And so on. In the development of paper feed rolls, how to improve wear resistance and friction coefficient retention within the appropriate dynamic elastic modulus (for example, E1 (22 ° C.)) set as described above. Is an issue.

  In the present invention, the balance of tan δ (22 ° C.) of the rubber cross-linked product for paper feed rolls at 22 ° C. with E1 (22 ° C.) optimized according to the part where the roller is used is shown in FIG. By setting it to be below the boundary indicated by a straight line, internal heat generation due to repeated deformation when used as a paper feed roll is suppressed, and rubber deformation is also reduced when the adhesion of the rubber surface is reduced due to paper dust adhesion. The reaction force due to is large, and this reaction force contributes to the paper conveying force. As a result, the abrasion resistance due to paper passing within the set value (unit: MPa) ± 2 MPa of E1 (22 ° C.) as an appropriate dynamic elastic modulus corresponding to the use part of the roller in the paper feeder. In addition, the coefficient of friction retention is good.

The rubber cross-linked product for a paper feed roll of the present invention has the following formula (5),
tan δ (22 ° C.) − (0.0031 × E1 (22 ° C.) + 0.04) ≦ 0 (5)
It is further preferable to satisfy The dotted line in FIG.
tan δ (22 ° C.) = 0.0031 × E1 (22 ° C.) + 0.04
Is shown. That is, it is preferable that the cross-linked rubber for paper feeding of the present invention has viscoelastic characteristics belonging to a region on the dotted line in FIG.

FIG. 2 is a diagram showing a relationship between E1 (22 ° C.) and A (E1), and FIG. 3 is a diagram showing a relationship between E1 (22 ° C.) and B (E1). The straight line in FIG. 2 is the following function:
A (E1) = − 0.0414 × E1 (22 ° C.) + 0.0750
Is shown. In addition, the straight line in FIG.
B (E1) = − 0.0066 × E1 (22 ° C.) + 0.0200
Is shown.

  That is, the rubber cross-linked product for a paper feed roll of the present invention has viscoelastic properties belonging to a region where A (E1) is larger than the straight line in FIG. 2 or the straight line in FIG. It is characterized by having any one of viscoelastic properties belonging to a region where B (E1) is large. In the present invention, A (E1) of the rubber cross-linked product is not less than the boundary indicated by the straight line in FIG. 2 in the balance with E1 (22 ° C.), or B (E1) of the rubber cross-linked product is E1 ( 22 [deg.] C.) in the balance with the straight line in FIG. In this case, since the interaction between the polymer main chains in the rubber cross-linked product for the paper feed roll is relatively small, in the paper feed roll, the rate of decrease in the friction coefficient μ during the transition from the normal temperature environment to the low temperature environment and The shrinkage of the diameter is reduced.

The rubber cross-linked product for a paper feed roll of the present invention has a measurement temperature: -84 ° C to 52 ° C, a temperature rising rate: 2 ° C / min, a measurement temperature interval: 4 ° C, a measurement frequency f: 10 Hz, an initial strain: 4 mm, and an amplitude. : 0.1 mm, sample size: width 4 mm x length 40 mm x thickness 2 mm, under the viscoelasticity measurement conditions, the following chemical formula (4)
T _max − (− 32 ° C.) ≦ 0 (4)
(In formula (4), T _max is the temperature at which tan δ (loss tangent) takes the maximum value under the above viscoelasticity measurement conditions)
It is preferable to satisfy. FIG. 4 is a diagram showing the relationship between E1 (22 ° C.) and T _max . That is, in the present invention, it is preferable that T _{max of the} rubber cross-linked product for paper feed rolls is set to −32 ° C. or less. In this case, the interaction between the polymer molecules of the rubber cross-linked product for paper feed rolls, particularly the crystallization arrangement of ethylene units in the ethylene propylene-diene copolymer, is relatively small, so even in use under low temperature conditions. The paper feed roll has a good coefficient of friction, and the roll outer diameter shrinkage when compared with the use at room temperature is small.

  The viscoelastic characteristics in the present invention, specifically, E1 (dynamic elastic modulus) and tan δ (loss tangent) are measured by a viscoelastic spectrometer. In addition, the value regarding the viscoelastic property in this specification is measured by the viscoelasticity spectrometer (VISCOELASTIC SPECTROMETER TYPE VES-F3) made from Iwamoto Seisakusho.

  Throughout this specification, the values of dynamic elastic modulus and loss tangent shall be values measured at a frequency of 10 Hz among the values measured at frequencies of 100, 80, 40, and 10 Hz. The viscoelastic property value at is measured from two measurement points close to the temperature, that is, from the measurement point adjacent to the high temperature side of the target temperature and the measurement value adjacent to the low temperature side. The substitute value is calculated by insertion.

Furthermore, T _max in this specification is a value calculated as follows. That is, in the measurement of tan δ (loss tangent), paying attention to a total of 5 measurement points, that is, the measurement point at which tan δ shows the maximum value and the two measurement points before and after that, the measurement temperature (unit: ° C.) The following quadratic function where x is x and tan δ is y:
y = ax ² + bx + c
To approximate. In the obtained quadratic approximate curve, x (temperature) (corresponding to −b / 2a) when y (tan δ) takes a maximum value is calculated as T _max (unit: ° C.).

  The polymer component employed in the rubber cross-linked product for paper feed rolls of the present invention contains an ethylene propylene-diene copolymer, but other rubbers include, for example, natural rubber, isoprene rubber, butadiene rubber, butyl rubber, and styrene butadiene rubber. Norbornene rubber, butadiene-nitrile rubber, chloroprene rubber, halogenated butyl rubber, acrylic rubber, epichlorohydrin rubber and the like can be preferably blended. These can be used alone or in combination of two or more.

  As the ethylene propylene-diene copolymer contained in the rubber cross-linked product for paper feed roll of the present invention, those having a relatively long chain branching structure are preferred. The ethylene propylene-diene copolymer having a relatively long chain branching structure forms a three-dimensional network structure with large gaps between the main chains, so that the crystallization arrangement of ethylene units in the ethylene propylene-diene copolymer Etc., the interaction between the polymer backbones is reduced. In addition, by having a long-chain branched structure, the entanglement points between polymer molecules increase, and the entanglement point has a role of a pseudo crosslinking point. For this reason, the use of an ethylene propylene-diene copolymer having a relatively long-chain branched structure effectively suppresses viscous flow, which is a major cause of deterioration in physical properties of rubber cross-linked products for paper feed rolls. Is advantageous. As a result, the loss tangent tan δ can be reduced while maintaining the dynamic elastic modulus E1, and high wear resistance can be maintained. Furthermore, by reducing the interaction between the main chains of the polymer molecules, it is possible to obtain a paper feed roll having a small reduction rate of the friction coefficient μ and a small amount of shrinkage of the outer diameter of the roll during the transition from the normal temperature environment to the low temperature environment. It becomes possible.

  As the ethylene propylene-diene copolymer having a relatively long chain branched structure, for example, using a dynamic viscoelasticity analyzer (Dynamic Mechanical Spectrometry = DMS), the phase angle at 0.1 rad / s and 100 rad / s Those having a difference of 35 or less, particularly 25 or less can be preferably employed.

  In the ethylene propylene-diene copolymer contained in the rubber cross-linked product for paper feed roll of the present invention, it is preferable that the ethylene unit and the propylene unit are randomly polymerized. In this case, as a result of suppressing the crystallization arrangement of the polymer main chain in a low temperature environment, there is an advantage that a decrease in the coefficient of friction and a shrinkage of the outer diameter of the roll are suppressed at a low temperature.

  In the present invention, the content of the ethylene unit in the ethylene propylene-diene copolymer is preferably adjusted to be 50% by mass or more and 63% by mass or less, further 62% by mass or less, and further 61% by mass. The following is preferable. When the ethylene unit content is 50% by mass or more, sufficient rotational mobility of the polymer main chain can be obtained, and a desired degree of crystallization arrangement of the polymer main chain during rubber stretching occurs. The mechanical strength of the object is increased and the wear resistance is improved. On the other hand, when the content of the ethylene unit is 63% by mass or less, excessive crystallization arrangement of the polymer main chain due to the ethylene unit is suppressed, and the decrease in the friction coefficient at low temperature and the shrinkage of the outer diameter of the roll are small. In addition, workability is also improved. In addition, content of the ethylene unit in an ethylene propylene-diene copolymer can be measured by ASTM D3900, for example.

  Moreover, it is preferable that content of the diene component in an ethylene propylene diene copolymer is 1.9 mass% or more and 13 mass% or less. When the content of the diene component is less than 1.9% by mass, the compression set characteristic and wear resistance of the rubber layer of the paper feed roll tend to decrease due to the low crosslinking density. When is more than 13% by mass, the weather resistance of the rubber layer tends to be lowered, and the retention of the friction coefficient due to paper passing tends to be lowered.

  In the present invention, in particular, the content of the ethylene propylene-diene copolymer is 90% by mass or more of the polymer component, and the content of the ethylene unit in the ethylene propylene-diene copolymer is 50% by mass or more and 61%. A polymer component having a mass% or less can be preferably used.

  Examples of the third component of the ethylene propylene-diene copolymer of the present invention include dicyclopentadiene, ethylidene norbornene, and 1,4-hexadiene, and ethylidene norbornene is particularly preferable. When ethylidene norbornene is used, the advantage of a high vulcanization rate is given.

  Examples of the ethylene propylene-diene copolymer having a long-chain branched structure used in the present invention include non-oil-extended rubbers such as “KELTAN 8340A” and “KELTAN 2340A” manufactured by DSM, and “KELTAN” manufactured by DSM. 7341A "(oil extended amount: 20 phr) and the like.

  The Mooney viscosity of the ethylene propylene-diene copolymer used in the present invention is preferably 80 or more and 150 or less, particularly preferably 85 or more and 150 or less in ML (1 + 4) (100 ° C.). Alternatively, ML (1 + 4) (125 ° C.) is preferably 55 or more and 110 or less, and particularly preferably 60 or more and 110 or less. When the Mooney viscosity is 80 or more at ML (1 + 4) (100 ° C.) or 55 or more at ML (1 + 4) (125 ° C.), the polymer molecular weight is sufficiently large, and the wear resistance is sufficiently secured. On the other hand, when Mooney viscosity is ML (1 + 4) (100 ° C.) of 150 or less, or ML (1 + 4) (125 ° C.) of 110 or less, there is an advantage that workability is good. The Mooney viscosity can be measured according to, for example, JIS K 6300.

  The ethylene propylene-diene copolymer used in the present invention may be a single copolymer or a mixture of two or more copolymers. When a mixture of two or more types of copolymers is used, the characteristic values defined in the present invention, such as ethylene unit content, branched structure, Mooney viscosity, are evaluated as average values calculated from the content ratio of each copolymer. The That is, when two or more ethylene propylene-diene copolymers are used in combination, those satisfying the above characteristic values and those not satisfying may be mixed, and the average of the total ethylene propylene-diene copolymers It suffices if the value satisfies the above characteristic value.

  In the present invention, when EPDM containing a softening agent such as oil-extended grade is used, the above Mooney viscosity value means only the value of the base polymer not containing the softening agent.

  It is preferable that E1 (22 degreeC) of the rubber crosslinked material for paper feed rolls of this invention shall be 1.5 MPa or more and 45 MPa or less. When E1 (22 ° C.) is less than 1.5 MPa, the rubber layer is greatly deformed with respect to the stress applied to the rubber layer, and it tends to be difficult to impart high wear resistance. When E1 (22 ° C.) is larger than 45 MPa, the contact area between the paper feed roll and the paper tends to be small, and it is difficult to ensure a good friction coefficient. The E1 (22 ° C.) of the rubber cross-linked product for paper feed rolls is preferably 2 MPa or more, more preferably 40 MPa or less, and particularly preferably 35 MPa or less.

  The rubber cross-linked product for paper feed rolls of the present invention can suppress an increase in hardness and E1 (dynamic elastic modulus) at a low temperature while reducing the blending amount of a softening agent that leads to a decrease in wear resistance. Thereby, there is an advantage that the rate of decrease in the coefficient of friction and the shrinkage amount of the outer diameter of the roll are reduced particularly when shifting from the normal temperature environment to the low temperature environment.

  The blending amount of the softening agent with respect to 100 parts by mass of the rubber cross-linked product for paper feed roll of the present invention is preferably 15 parts by mass or less, particularly preferably 5 parts by mass or less. The softener in the present invention includes an oil component and a plasticizer component. When the blending amount of the softening agent is more than 15 parts by mass, the wear resistance of the paper feed roll tends to be easily impaired. In the present invention, it is particularly preferable not to add a softener. For example, even an oil-extended polymer that contains a large amount of oil as a softening agent can be softened to the entire polymer component by mixing with other polymers that have a low softener content or no softening agent at all. What is necessary is just to set so that the compounding quantity of an agent may satisfy | fill the said.

  In addition, the compounding agent normally used in manufacture of a rubber product can be used suitably for the rubber crosslinked material for paper feed rolls of this invention. Specifically, for example, in addition to fillers such as carbon black, silica, titanium oxide, calcium carbonate, talc, and clay, and crosslinking agents, vulcanization accelerators, anti-aging agents, processing aids, and the like can be blended.

  As the crosslinking mechanism in the production of the rubber cross-linked product for paper feed rolls of the present invention, sulfur crosslinking, peroxide crosslinking, resin crosslinking and the like can be adopted, but sulfur crosslinking is preferably adopted. In this case, sulfur is preferably used as the crosslinking agent, and the amount of simple sulfur is preferably 1 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the polymer component. If the amount of elemental sulfur is 1 part by mass or more, the crosslink density is sufficiently secured and wear resistance is good. If it is 5 parts by mass or less, increase in compression set is prevented and sulfur bloom ( (Precipitation) is less likely to occur.

  The paper feed roll of the present invention can be used not only for paper but also for various recording materials such as plastic sheets such as OHP sheets, fabrics, and metal sheets.

[Example]
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

(Preparation of paper feed roll 1)
FIG. 5 is a diagram showing the shape of the paper feed roll 1. The compounding components shown in Table 1 and Table 2 are kneaded using a kneader, and vulcanized and molded in a predetermined mold at 160 ° C. for 30 minutes to form a rubber cross-linked product for a cylindrical paper feed roll. Got. The rubber layer 51 is inserted into a stainless steel shaft core 52 as shown in FIG. 5, the surface of the rubber layer is polished, and the paper of the examples and comparative examples composed of the rubber layer 51 and the shaft core 52. A feed roll 1 was produced. The rubber layer 51 has an outer diameter of 16 mm, an inner diameter of 8 mm, and a length of 10 mm.

(Preparation of paper feed roll 2)
FIG. 6 is a diagram showing the shape of the paper feed roll 2. The compounding components shown in Table 1 and Table 2 are kneaded using a kneader, and vulcanized and molded in a predetermined mold at 160 ° C. for 30 minutes to form a rubber cross-linked product for a cylindrical paper feed roll. Got. The rubber layer 61 is inserted into a stainless steel shaft core 62 as shown in FIG. 6, the surface of the rubber layer is polished, and the paper of the examples and comparative examples composed of the rubber layer 61 and the shaft core 62. A feed roll 2 was produced. The rubber layer has an outer diameter of 20 mm, an inner diameter of 10 mm, and a length of 30 mm.

（注１）８３４０Ａは、ＤＳＭ社製のエチレンプロピレン−ジエン共重合体（ＥＰＤＭ）「ＫＥＬＴＡＮ ８３４０Ａ」である。
（注２）ＥＰ１０３ＡＦは、ＪＳＲ社製のエチレンプロピレン−ジエン共重合体（ＥＰＤＭ）である。
（注３）ＥＰ２５は、ＪＳＲ社製のエチレンプロピレン−ジエン共重合体（ＥＰＤＭ）である。
（注４）ＥＰ５７Ｃは、ＪＳＲ社製のエチレンプロピレン−ジエン共重合体（ＥＰＤＭ）である。
（注５）５５０８は、ＤＳＭ社製のエチレンプロピレン−ジエン共重合体（ＥＰＤＭ）「ＫＥＬＴＡＮ ５５０８」である。
（注６）Ｅ５８６は、住友化学社製のエチレンプロピレン−ジエン共重合体（ＥＰＤＭ）である。
（注７）ＥＰ３５は、ＪＳＲ社製のエチレンプロピレン−ジエン共重合体（ＥＰＤＭ）である。
（注８）ＥＰ３７Ｆは、ＪＳＲ社製のエチレンプロピレン−ジエン共重合体（ＥＰＤＭ）である。
（注９）ステアリン酸は、花王社製の商品名「ルナックＳ−３０」である。
（注１０）酸化亜鉛は、正同化学社製の商品名「亜鉛華１号」である。
（注１１）炭酸カルシウムは、白石工業社製の「白艶華ＣＣ」である。
（注１２）ＧＰＦカーボンは、旭カーボン社製の商品名「旭＃５５」である。
（注１３）ＨＡＦカーボンは、旭カーボン社製の商品名「旭＃７０Ｈ」である。
（注１４）硫黄は、鶴見化学社製の商品名「粉末硫黄」である。
（注１５）ＤＭは、大内新興化学社製の商品名「ノクセラーＤＭ」である。
（注１６）ＴＥＴは、大内新興化学社製の商品名「ノクセラーＴＥＴ」である。
（注１７）ＴＲＡは、大内新興化学社製の商品名「ノクセラーＴＲＡ」である。
（注１８）ＢＺは、大内新興化学社製の商品名「ノクセラーＢＺ」である。
（注１９）ＴＴＣＵは、大内新興化学社製の商品名「ノクセラーＴＴＣＵ」である。

(Note 1) 8340A is an ethylene propylene-diene copolymer (EPDM) “KELTAN 8340A” manufactured by DSM.
(Note 2) EP103AF is an ethylene propylene-diene copolymer (EPDM) manufactured by JSR.
(Note 3) EP25 is an ethylene propylene-diene copolymer (EPDM) manufactured by JSR.
(Note 4) EP57C is an ethylene propylene-diene copolymer (EPDM) manufactured by JSR.
(Note 5) 5508 is an ethylene propylene-diene copolymer (EPDM) “KELTAN 5508” manufactured by DSM.
(Note 6) E586 is an ethylene propylene-diene copolymer (EPDM) manufactured by Sumitomo Chemical Co., Ltd.
(Note 7) EP35 is an ethylene propylene-diene copolymer (EPDM) manufactured by JSR.
(Note 8) EP37F is an ethylene propylene-diene copolymer (EPDM) manufactured by JSR.
(Note 9) Stearic acid is trade name “Lunac S-30” manufactured by Kao Corporation.
(Note 10) Zinc oxide is a trade name “Zinc Hana 1” manufactured by Shodo Chemical Co., Ltd.
(Note 11) Calcium carbonate is “Shiraka Hana CC” manufactured by Shiroishi Kogyo Co., Ltd.
(Note 12) GPF carbon is a trade name “Asahi # 55” manufactured by Asahi Carbon Co., Ltd.
(Note 13) HAF carbon is a product name “Asahi # 70H” manufactured by Asahi Carbon Co., Ltd.
(Note 14) Sulfur is a trade name “powder sulfur” manufactured by Tsurumi Chemical Co., Ltd.
(Note 15) DM is a trade name “Noxeller DM” manufactured by Ouchi Shinsei Chemical Co., Ltd.
(Note 16) TET is a trade name “Noxeller TET” manufactured by Ouchi Shinsei Chemical Co., Ltd.
(Note 17) TRA is a trade name “Noxeller TRA” manufactured by Ouchi Shinsei Chemical Co., Ltd.
(Note 18) BZ is the trade name “Noxeller BZ” manufactured by Ouchi Shinsei Chemical Co., Ltd.
(Note 19) TTCU is a trade name “Noxeller TTCU” manufactured by Ouchi Shinsei Chemical Co., Ltd.

(Characteristic evaluation)
<E1 (dynamic elastic modulus)>
The compounding ingredients shown in Table 1 and Table 2 were kneaded using a kneader and vulcanized using a sheet-like mold at 160 ° C. for 30 minutes to obtain a sheet-like rubber cross-linked product. . From this sheet, strip-shaped samples of width 4 mm × length 40 mm × thickness 2 mm of the examples and comparative examples were punched out. Using the above sample, a viscoelastic spectrometer (VISCOELASTIC SPECTROMETER TYPE VES-F3) manufactured by Iwamoto Seisakusho, the following conditions:
Measurement temperature: -84 ° C to 52 ° C
Rate of temperature increase: 2 ° C / min
Measurement temperature interval: 4 ° C
Measurement frequency: 100, 80, 40, 10 Hz
Initial strain: 4mm
Amplitude: 0.1 mm
Under the measurement conditions, E1 (dynamic elastic modulus) [MPa] was measured, and a measurement value at a measurement frequency of 10 Hz was employed. Here, for viscoelastic property values at temperatures other than the measurement point, the measurement values at two measurement points close to the temperature, that is, the measurement point adjacent to the high temperature side of the target temperature and the low temperature side The substitute value calculated by interpolation from the measured value at the measurement point was used. The results are shown in Table 3 and Table 4.

<Tan δ (loss tangent)>
About the sample produced above, tan-delta (loss tangent) was measured on the same conditions as said E1 (dynamic elastic modulus). The results are shown in Table 3 and Table 4.

<A (E1)>
In the measurement of E1 (dynamic elastic modulus), the least square method was used for the relationship between the measured value (unit: MPa) of E1 (dynamic elastic modulus) in the range of 10 ° C. to 30 ° C. and the measurement temperature. A (E1) is the value of the slope (unit: MPa / ° C.) of the approximate straight line obtained by the primary approximation (however, only those whose correlation coefficient R ² is R ² ≧ 0.8 is valid). Calculated.

<B (E1)>
In the measurement of E1 (dynamic elastic modulus), the least square method was used for the relationship between the measured value (unit: MPa) of E1 (dynamic elastic modulus) in the range of 20 ° C. to 40 ° C. and the measurement temperature. The value of the slope (unit: MPa / ° C.) of the approximate straight line obtained by the primary approximation (however, only those whose correlation coefficient R ^{2 of the} approximate straight line is R ² ≧ 0.8 is valid) is B (E1) Calculated.

<T _max >
In the above measurement of tan δ (loss tangent), attention is paid to a total of 5 measurement points, that is, the measurement point where tan δ shows the maximum value and two measurement points before and after the measurement point. ) Is x and tan δ is y.
y = ax ² + bx + c
Approximated by In the obtained quadratic approximate curve, x (temperature) (corresponding to −b / 2a) when y (tan δ) takes a maximum value was calculated as T _max (unit: ° C.).
The results are shown in Table 3, Table 4 and FIG.

<Tan δ (22 ° C.)-P1>
From the values of E1 and tan δ determined above, tan δ (22 ° C.) − P1 was calculated. However,
P1 = 0.0031 × E1 (22 ° C.) + 0.0503
It is. The results are shown in Table 3 and Table 4.

<A (E1) -P2>
A (E1) -P2 was calculated from the value of A (E1) obtained above. However,
P2 = −0.0414 × E1 (22 ° C.) + 0.0750
It is. The results are shown in Table 3 and Table 4.

<B (E1) -P3>
B (E1) -P3 was calculated from the value of B (E1) obtained above. However,
P3 = −0.0066 × E1 (22 ° C.) + 0.0200
It is. The results are shown in Table 3 and Table 4.

なお、表中におけるＭＬ（１＋４）（１００℃）、ＭＬ（１＋４）（１２０℃）、ＭＬ（１＋４）（１２５℃）の値は、ＩＳＯ２８９（ＡＳＴＭ Ｄ １６４６）、エチレン含量はＡＳＴＭ Ｄ ３９００：Ａ（ＩＩＳＲＰ）によって測定される値である。

In the table, ML (1 + 4) (100 ° C.), ML (1 + 4) (120 ° C.), ML (1 + 4) (125 ° C.) values are ISO289 (ASTM D 1646), and ethylene content is ASTM D 3900: A. It is a value measured by (IISRP).

<Decrease rate of friction coefficient μ during transition from normal temperature environment to low temperature environment>
FIG. 7 is a diagram illustrating a method for evaluating the wear coefficient. The paper feed roll 1 produced above is allowed to stand for at least half a day under the following LL condition or NN condition, and then the paper feed roll having the rubber layer 72 formed on the outer periphery of the shaft core 71 and the Teflon (registered trademark) plate 73. A paper 74 (Green 100 paper manufactured by Fuji Xerox Co., Ltd.) connected to the load cell 75 is sandwiched between them, and a vertical load W (unit: N) is applied to the paper by applying a load to the rotating shaft of the paper feed roll. A conveyance force F (unit: N) acting when the paper feed roll is rotated in the direction of arrow a at the following rotation speed, that is, the peripheral speed of the roll outer peripheral surface (hereinafter the same) is measured by the load cell 75. The formula of
Friction coefficient μ = F (unit: N) / W (unit: N)
From the above, the friction coefficient μ was calculated. The friction coefficient μ under the following conditions was determined as μ (A), μ (B), and μ (C), respectively.
μ (A)
Leave condition: LL condition (temperature 10 ° C, relative humidity 15%)
Vertical load W: 1N
Rotational speed: 30 mm / sec μ (B)
Leave condition: LL condition (temperature 10 ° C, relative humidity 15%)
Vertical load W: 2.55N
Rotational speed: 300mm / sec μ (C)
Standing condition: NN condition (temperature 22 ° C, relative humidity 55%)
Vertical load W: 2.55N
Rotational speed: as a rate of change of 300 mm / second μ, ratio μ (A) / μ (C) between μ (A) and μ (C), and ratio μ (B) between μ (B) and μ (C) / Μ (C) was determined as a percentage. As μ (A) / μ (C) and μ (B) / μ (C) are larger, the rate of decrease in the friction coefficient μ is smaller when left under LL conditions than when left under NN conditions. . The results are shown in Tables 5 and 6.

  FIG. 8 is a diagram showing the relationship between A (E1) -P2 and μ (A) / μ (C) in Examples and Comparative Examples, and FIG. 9 shows A (E1) − in Examples and Comparative Examples. It is a figure which shows the relationship between P2 and μ (B) / μ (C). FIG. 10 is a diagram showing the relationship between B (E1) -P3 and μ (A) / μ (C) in the examples and comparative examples, and FIG. 11 shows B (E1) in the examples and comparative examples. It is a figure which shows the relationship between -P3 and (micro | micron | mu) (B) / micro (C).

<Change in roll outer diameter during transition from normal temperature environment to low temperature environment>
The paper feed roll 1 produced as described above is allowed to stand for more than half a day in each of the LL condition (temperature 10 ° C., relative humidity 15%) and the NN condition (temperature 22 ° C., relative humidity 55%). , Measured using a laser dimension measuring machine ("LS-3100" manufactured by Keyence Corporation), and the outer diameter change amount as an index of the outer diameter change amount of the roll at the transition from the normal temperature environment to the low temperature environment,
Change in outer diameter (mm) = (roll outer diameter after leaving LL condition (mm)) − (roll outer diameter after leaving NN condition (mm))
It was evaluated by. The closer the value is to 0, the smaller the shrinkage of the outer diameter of the roll when left under the LL condition than when left under the NN condition. The roll outer diameter change amount was calculated as an average value of the measured values of the four paper feed rolls. The results are shown in Tables 5 and 6.

<Μ retention after passing paper>
The paper feed roll 2 produced above was left under NN conditions (temperature 22 ° C., relative humidity 55%) for 6 hours or more, and then the initial μ was measured by the evaluation method shown in FIG. That is, paper 74 (Green 100 paper of Fuji Xerox Co., Ltd.) connected to the load cell 75 is sandwiched between a paper feed roll in which a rubber layer 72 is formed on the outer periphery of the shaft core 71 and a Teflon (registered trademark) plate 73, and paper is fed. By applying a load to the rotating shaft of the roll, the rubber layer 72 was pressed with a vertical load W = 2.55 N on the paper. Next, a conveyance force F (unit: N) acting on the paper 74 when the paper feed roll is rotated in the direction of arrow a at a rotational speed of 300 mm / sec under the conditions of a temperature of 22 ° C. and a relative humidity of 55%. Is measured by the load cell 75, and the following formula:
Friction coefficient μ = F (unit: N) / W (unit: N)
The friction coefficient μ (initial μ) was determined according to

Next, the paper feed roll 2 was attached to the third tray of Fuji Xerox's Color Document 60, and at the room temperature, Fuji Xerox's Green100 paper (A4) was fed by 340000 sheets by cross feed. The coefficient of friction of the paper feed roll after passing the paper was measured by the same method as the above initial μ, and was defined as the residual μ after passing the paper. The μ retention after passing paper is expressed by the following formula:
Μ retention after passing (%) = (remaining μ after passing) / (initial μ) × 100
It was evaluated by. The closer the value is to 100%, the better the μ retention after paper passing. The results are shown in Tables 5 and 6.

<Change in outer diameter after passing paper>
About the paper feed roll 2 produced above, the roll outer diameter at the initial stage and after passing 340000 sheets was left under NN conditions using a laser dimension measuring machine ("LS-3100" manufactured by Keyence Corporation), and then the NN conditions were satisfied. The amount of change in the outer diameter (mm) after passing the paper is expressed by the following equation:
Change amount of outer diameter after passing paper (mm) = (Outer diameter of roll after passing paper (mm)) − (Outer diameter of initial roll (mm))
It was expressed by an index with Comparative Example 9 taken as 100. The smaller the value, the better the wear resistance of the roll. The results are shown in Tables 5 and 6.

表３、表４、および図１〜図３に示すように、実施例の紙送りロール用ゴム架橋物は、本発明における式（１)と式（２）および／または式（３）とを同時に満たしており、比較例のゴム架橋物は式（１)と式（２）および／または式（３）とを同時には満たしていない。

As shown in Tables 3 and 4 and FIGS. 1 to 3, the rubber cross-linked product for paper feed rolls of the examples has the formula (1) and the formula (2) and / or the formula (3) in the present invention. It is satisfy | filled simultaneously and the rubber crosslinked material of a comparative example does not satisfy | fill Formula (1), Formula (2), and / or Formula (3) simultaneously.

  As shown in Tables 5 and 6 and FIGS. 8 to 11, in the paper feed roll of the example, the value of μ (A) / μ (C) tends to be larger than that of the comparative example, and μ (B) / Μ (C) is equivalent or better. Further, the shrinkage amount of the outer diameter at the time of transition from the NN environment to the LL environment tends to be smaller than that of the comparative example. Therefore, in the Example, it turns out that the fall rate of a friction coefficient when changing to LL environment from NN environment is small, and the shrinkage | contraction amount of a roll outer diameter is small. Further, in the paper feed roll of the example, the retention rate of the friction coefficient μ after the paper passing and the amount of change in the outer diameter after the paper passing are also good. From these results, the paper feed roll using the rubber cross-linked product for the paper feed roll according to the present invention maintains a good wear resistance, while reducing the friction coefficient μ during the transition from the normal temperature environment to the low temperature environment and It can be seen that the shrinkage amount of the roll outer diameter is small.

Among them, Examples 1 to 5 and Examples in which the ethylene content in the ethylene propylene-diene copolymer is 62% by mass or less and satisfies the formula (1), formula (2) and / or formula (3) in the present invention. In 8-14, compared with Example 6 whose ethylene content in an ethylene propylene-diene copolymer is larger than 62 mass%, and _Tmax whose _Tmax is higher than -32 degreeC, the transition from a normal temperature environment to a low temperature environment is further carried out. It can be seen that the shrinkage of the outer diameter of the roll at that time is small.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The paper feed roll using the rubber cross-linked product for the paper feed roll of the present invention has good wear resistance, and the reduction rate of the friction coefficient μ and the shrinkage of the outer diameter of the roll at the transition from the normal temperature environment to the low temperature environment. Since the amount is small, good and stable paper feeding performance can be exhibited even when used under low temperature conditions.

It is a figure which shows the relationship between E1 (22 degreeC) and tan-delta (22 degreeC). It is a figure which shows the relationship between E1 (22 degreeC) and A (E1). It is a figure which shows the relationship between E1 (22 degreeC) and B (E1). It is a figure which shows the relationship between E1 (22 degreeC) and _Tmax . FIG. 3 is a diagram showing the shape of a paper feed roll 1 FIG. 3 is a diagram showing the shape of a paper feed roll 2 It is a figure explaining the evaluation method of a friction coefficient. It is a figure which shows the relationship between A (E1) -P2 and (mu) (A) / (mu) (C) of an Example and a comparative example. It is a figure which shows the relationship between A (E1) -P2 of an Example and a comparative example, and (mu) (B) / (mu) (C). It is a figure which shows the relationship between B (E1) -P3 of an Example and a comparative example, and (mu) (A) / (mu) (C). It is a figure which shows the relationship between B (E1) -P3 of an Example and a comparative example, and (mu) (B) / (mu).

Explanation of symbols

  51, 61, 72 Rubber layer, 52, 62, 71 Axle, 73 Teflon (registered trademark) board, 74 paper, 75 load cell.

Claims (9)

A rubber cross-linked product for paper feed rolls containing at least a polymer component, wherein the polymer component contains an ethylene propylene-diene copolymer, and the measurement temperature in the rubber cross-linked product for paper feed rolls is -84 ° C to 52 ° C. Dynamic elastic modulus E1 [MPa measured under viscoelasticity measurement conditions of ° C., heating rate: 2 ° C./min, measurement temperature interval: 4 ° C., measurement frequency f: 10 Hz, initial strain: 4 mm, amplitude: 0.1 mm ] And loss tangent tan δ have the following formula (1),
tan δ (22 ° C.) − (0.0031 × E1 (22 ° C.) + 0.0503) ≦ 0 (1)
(In formula (1), E1 (22 ° C.) and tan δ (22 ° C.) are values of dynamic elastic modulus E1 [MPa] and loss tangent tan δ at 22 ° C., respectively.)
And the following formula (2) and / or formula (3),
A (E1) − (− 0.0414 × E1 (22 ° C.) + 0.0750) ≧ 0 (2)
(In Formula (2), A (E1) is an approximate straight line obtained by linear approximation using the method of least squares from the relationship between the measured temperature and the measured temperature of the dynamic elastic modulus E1 at 10 to 30 ° C.) And the slope of the approximate straight line where the correlation coefficient R ² ≧ 0.8 (unit: MPa / ° C.)),
B (E1) − (− 0.0066 × E1 (22 ° C.) + 0.0200) ≧ 0 (3)
(In Formula (3), B (E1) is an approximate straight line obtained by linear approximation using the method of least squares from the relationship between the measured temperature and the measured temperature of the dynamic elastic modulus E1 at 20 to 40 ° C. And the slope of the approximate straight line where the correlation coefficient R ² ≧ 0.8 (unit: MPa / ° C.)),
A rubber cross-linked product for paper feed rolls that satisfies the requirements. The following formula (4),
T _max − (− 32 ° C.) ≦ 0 (4)
(In formula (4), T _max is the temperature (unit: ° C.) at which tan δ (loss tangent) takes the maximum value under the viscoelasticity measurement conditions)
The rubber cross-linked product for a paper feed roll according to claim 1, wherein   The rubber cross-linked product for paper feed rolls according to claim 1 or 2, wherein the ethylene unit content in the ethylene propylene-diene copolymer is 50 mass% or more and 63 mass% or less.   The rubber cross-linked product for a paper feed roll according to any one of claims 1 to 3, wherein the content of the ethylene propylene-diene copolymer in the polymer component is 50% by mass or more.   The content of the ethylene propylene-diene copolymer in the polymer component is 90% by mass or more, and the content of the ethylene unit in the ethylene propylene-diene copolymer is 50% by mass or more and 62% by mass or less. The rubber cross-linked product for a paper feed roll according to claim 1 or 2, wherein   The content of the ethylene propylene-diene copolymer in the polymer component is 90% by mass or more, and the content of the ethylene unit in the ethylene propylene-diene copolymer is 50% by mass or more and 61% by mass or less. The rubber cross-linked product for a paper feed roll according to claim 1 or 2, wherein   The rubber cross-linked product for a paper feed roll according to any one of claims 1 to 6, wherein a blending amount of the softening agent with respect to 100 parts by mass of the polymer component is 15 parts by mass or less.   The rubber cross-linked product for paper feed roll according to any one of claims 1 to 7, which is cross-linked by sulfur.   The paper feed roll which used the rubber crosslinked material for paper feed rolls in any one of Claims 1-8 for the rubber layer.

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