JP2002069264A - Thermoplastic elastomer composition and rubber roller using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition that is excellent in moldability and durability, and provide a rubber roller formed from the composition that is used in an ink-jet printer or the like and especially exhibits good affinity with a recording liquid. SOLUTION: The thermoplastic elastomer composition is produced by mixing (A) a thermoplastic elastomer composition comprising a high-molecular weight styrene thermoplastic elastomer having a number average molecular weight of not less than 80,000, (B) a composition comprising a polar terminal-modified thermoplastic elastomer and/or a graft polymer of a polar polymer and a non- polar polymer and (C) a rubber compound comprising EPDM as the predominant component, wherein the rubber in the mixture is dynamically crosslinked and is dispersed in the thermoplastic elastomer. The rubber roller is produced by molding the thermoplastic elastomer composition into a roller of a tubular or cylindrical form.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic elastomer composition in which a dynamically crosslinked rubber is dispersed and a rubber roller formed from the composition, and more particularly to a paper feed for an ink jet printer which is required to have good compatibility with a recording liquid. It is preferably used for a roller.

[0002]

2. Description of the Related Art A rubber roller is used for a paper feeding mechanism in an ink jet printer, a laser printer, an electrostatic copying machine, a plain paper facsimile machine, an automatic teller machine (ATM) and the like. Since the rubber roller needs to pick up and separate a conveyed object such as paper or film and feed the paper while separating, excellent flexibility and high abrasion resistance are required.

Among the paper feed rollers, a rubber roller for paper supply used in an ink jet printer is required to have a good affinity (compatibility) with a recording liquid (aqueous ink). This is because the ink jet recording liquid contains a large amount of polar components such as water and polyhydric alcohol, and if the affinity with the recording liquid (polarity) is low, the ink may not reach the portion that comes into contact with the rubber roller during paper feeding. This is because the inconvenience of poor recording liquid application and roller marks remains.

[0004] As a rubber roller of this type, the applicant of the present invention disclosed in Japanese Patent Application No. 11-372620, a hydrogenated styrene-based thermoplastic elastomer and an olefin-based resin were mixed with a rubber component, and the rubber component was converted into a resin. A rubber roller comprising a thermoplastic elastomer composition in which rubber is dispersed in the hydrogenated styrene-based thermoplastic elastomer and an olefin-based resin by dynamic crosslinking with a crosslinking agent is provided.

[0005] In the above thermoplastic elastomer composition, the amount of halogen addition is specified as 0.25 to 1.5% by weight as a resin crosslinking agent, or a combination of a halogenated resin crosslinking agent and a non-halogenated resin crosslinking agent is used in combination. By doing so, the dynamic crosslinking speed is controlled so that the crosslinking of the rubber component is completed when the mixing of the rubber and the resin has progressed to some extent. By this method, the moldability and the dispersibility of the rubber are ensured, and the rubber component in the resin can be increased. As described above,
By improving the dispersibility of the rubber, the flexibility of the molded rubber roller is increased without impairing the durability, the transportability at the time of paper feeding is improved, and the wear resistance is also improved. Further, by increasing the rubber component, it is possible to further increase the conveying force at the time of paper feeding, to achieve durability and to reduce the generation of wear powder.

In the same manner as described above, Patent Document 2 discloses that rubber is dynamically crosslinked in two or more kinds of thermoplastic elastomers.
No. 837741 discloses an ethylene-α-olefin copolymer rubber, a crystalline ethylene-propylene block copolymer resin, a low-molecular-weight propylene homopolymer resin having a number average molecular weight of 2,000 to 20,000, and a mineral oil-based softener, A thermoplastic elastomer composition dynamically crosslinked using a resin crosslinking agent is provided.

[0007]

However, in the above-mentioned prior application filed by the present applicant, the crosslinking speed is controlled to be low in order to increase the dispersibility of the rubber, so that the crosslinking density is low. For this reason, there is a problem that the mechanical properties are deteriorated, and especially the durability is deteriorated, and the paper passing performance is deteriorated when used as a paper feed roller. Further, since there is a limit to the increase of the rubber component, there is a problem that generation of abrasion powder cannot be significantly reduced and durability cannot be sufficiently improved. If the crosslinking speed is increased by increasing the crosslinking speed in order to solve the above problem, there is a problem that the dispersibility of the rubber component is deteriorated and the flexibility is reduced. On the other hand, in the thermoplastic elastomer composition disclosed in Japanese Patent No. 2837741 described later, polypropylene is used as a low molecular weight component. Since polypropylene is not an elastomer, mechanical properties (particularly, flexibility) are used.
There is a problem that lowers.

In each of the above thermoplastic elastomer compositions, a non-polar material such as an olefin resin is used, but no consideration is given to compatibility with a recording liquid such as an aqueous ink (polar). Therefore, using a rubber roller as a paper feed roller for an ink jet printer, super fine glossy paper, photo print paper, color OH
When printing on P paper or the like, there is a case where the recording liquid spreads poorly on a portion contacted by a roller when the paper is fed, and a roller mark remains on that portion to disturb the image. Therefore, it is required that the rubber roller made of the thermoplastic elastomer composition has good affinity with the water-soluble recording liquid (polarity).

The present invention has been made in view of the above problems, and has been used as a paper feed roller in an ink jet printer or the like, has a good affinity for a recording liquid, particularly a polar aqueous ink, and has been printed on paper with the recording liquid. A first object is to provide a rubber roller that does not sometimes leave a roller mark on a printed portion. Another object of the present invention is to provide a thermoplastic elastomer composition which is excellent in flexibility, abrasion resistance, durability and moldability and is excellent as a material for forming the rubber roller.

[0010]

In order to solve the above-mentioned problems, the present invention provides a thermoplastic elastomer composition (A) containing a high-molecular-weight styrene-based thermoplastic elastomer having a number average molecular weight of 80,000 or more; A composition (B) comprising a modified thermoplastic elastomer and / or a polar-nonpolar graft polymer is mixed with a rubber compound (C) containing EPDM as a main component, and the rubber in the mixture is dynamically crosslinked. There is provided a thermoplastic elastomer composition which is dispersed in the thermoplastic elastomer.

As described above, in the present invention, since the composition (B) comprising the polar terminal-modified thermoplastic elastomer and / or the polar-non-polar graft polymer is contained, the rubber roller comprising the elastomer composition is used in an ink jet printer. When used as a paper feed roller for printing, affinity with a recording liquid, particularly, a polar aqueous ink is improved, and a good image can be obtained without leaving any roller marks. The presence of the polar portion and the non-polar portion improves the affinity between the aqueous ink (polar) and the material (non-polar) such as olefin resin and EPDM. As the polar terminal modification, those modified to hydroxyl groups are preferable, but other polar groups may be used as long as there is no problem with compatibility with the olefin resin, styrene-based thermoplastic elastomer, EPDM, or the like that is the skeleton of the material. May be.

The thermoplastic elastomer composition (A) contains a terminal-unmodified low-molecular-weight styrene-based thermoplastic elastomer having a number average molecular weight of 70,000 or less, and the rubber compound (C) contains 100% by weight of rubber. % Or less oil based on the above (A)
(B) A resin composition (D) containing 50% by weight or less of an olefin-based resin as a main component relative to 100% by weight of rubber of the rubber compound (C), and a mixture of the rubber compound (C) and the rubber compound (C). 500% by weight or less of a softening agent (E) with respect to 100% by weight of rubber of C), and a resin crosslinking agent (F)
May be included.

In particular, as described above, regardless of whether the terminal is modified or unmodified, the rubber contains a low-molecular-weight styrene-based thermoplastic elastomer having a number average molecular weight of 70,000 or less, more preferably 60,000 or less. Dispersion by dynamic cross-linking in the thermoplastic elastomer prevents deterioration of the dispersibility of the rubber component that occurred when only a high-molecular-weight thermoplastic elastomer was used. With good dispersibility, processability is greatly improved.

The reason why the number average molecular weight of the high molecular weight styrene-based thermoplastic elastomer in the above (A) is 80,000 or more is because of its mechanical properties (abrasion resistance and durability), and preferably 150,000. The number is more preferably 250,000 or more. On the other hand, the reason why the number average molecular weight of the terminal unmodified low molecular weight thermoplastic elastomer contained in (A) is 70,000 or less, preferably 10,000 to 60,000 is that the moldability and processability are improved, This is because the dispersibility of the polymer is improved. In the case of using both, preferred combinations can be appropriately selected by those skilled in the art. For example, a styrene-ethylene-ethylene / propylene-styrene copolymer having a molecular weight of 80,000 or more (S
EEPS) and styrene-ethylene having a molecular weight of 70,000 or less /
Propylene-styrene copolymer (SEPS) or SEE
PS is particularly preferred. In addition, styrene-ethylene-styrene copolymer (SES), SEPS, SEEPS, styrene-ethylene / butylene-styrene copolymer (SE
BS) etc. can be used as appropriate.

As the high-molecular-weight styrene-based thermoplastic elastomer, the terminal-unmodified low-molecular-weight thermoplastic elastomer, and the polar-terminal-modified thermoplastic elastomer, hydrogenated styrene-based thermoplastic elastomers are suitably used.

The hydrogenated styrene-based thermoplastic elastomer has a double bond saturated by hydrogenation, has a low hardness and a large friction coefficient. Because the double bond is gone,
Since the rubber composition is not crosslinked by reacting with a crosslinking agent during dynamic crosslinking, the crosslinking of the rubber is not hindered, and the elastomer composition after dynamic crosslinking exhibits the desired plasticity. Therefore, in the present invention, it is preferable to use a styrene-based thermoplastic elastomer which has been hydrogenated to such an extent that it is not crosslinked during dynamic crosslinking. Examples of the hydrogenated styrene-based thermoplastic elastomer include styrene-ethylene-styrene copolymer (SES), styrene-ethylene / propylene-styrene copolymer (SEPS), and styrene-ethylene-ethylene / propylene-styrene copolymer. (SEEPS), styrene-ethylene / butylene-styrene copolymer (SE
BS) and the like.

The polar terminal-modified thermoplastic elastomer in the above (B) is, for example, a hydroxyl group-modified low molecular weight SEE
PS and others. The polar-non-polar graft polymer in the above (B) includes, for example, polyethylene glycol-grafted polyethylene. By containing the polar terminal-modified thermoplastic elastomer in the above (B), the affinity with the polar recording liquid is improved due to the influence of hydroxyl terminal.
In addition, by containing a polar-non-polar graft polymer, a polar portion is introduced, and the affinity with an inkjet recording liquid (polar) is improved.

Examples of the softener include oils and plasticizers. As the oil, for example, a known synthetic oil composed of a mineral oil such as a paraffinic, naphthenic, or aromatic hydrocarbon or a hydrocarbon oligomer, or a process oil can be used. As the synthetic oil, for example, an oligomer of α-olefin, an oligomer of butene, and an amorphous oligomer of ethylene and α-olefin are preferable. Examples of the plasticizer include dioctyl phthalate (DO)
P), dibutyl phthalate (DBP), dioctyl sepate (DOS), dioctyl adipate (DOA), and the like can be used as long as the compatibility with the non-polar rubber or the like deteriorates and no roller mark remains.

When the softener is an oil, it is added in an amount of not more than 600% by weight, preferably 25 to 400% by weight, based on 100% by weight of the rubber. The reason why the amount of the oil is set to 600% by weight or less is that if it exceeds 600% by weight, the oil bleeds from the surface of the dynamically crosslinked product or the oil inhibits the crosslinking, so that the rubber component is not sufficiently crosslinked and the physical properties are not increased. Is reduced.
When the softening agent is a plasticizer, 15 to 400% by weight, preferably 25 to 200% by weight is added.

It is preferable to mix the resin mixture (D) containing the above-mentioned olefin resin as a main component, because the abrasion resistance can be improved. As the olefin resin in the resin mixture (D) containing the olefin resin as a main component, any commercially available olefin resin can be used, and polyethylene, polypropylene, ethylene ethyl acrylate resin, ethylene vinyl acetate resin, ethylene methacrylic acid can be used. Resins, ionomer resins and the like. The resin mixture (D) is
Further, it may contain a polyester resin, chlorinated polyethylene or the like.

Resin composition (D) containing an olefin resin as a main component with respect to 100% by weight of rubber (excluding softener)
Is preferred because it can improve wear resistance. More preferably, it is 40% by weight or more.
% By weight or less, more preferably 4% by weight or more and 35% by weight
It is as follows.

As the rubber component other than EPDM in the rubber compound containing EPDM (ethylene-propylene-diene rubber) as the main component (C), a diene rubber is preferable, and natural rubber (NR) and butadiene rubber (BR) are used. ,
Styrene butadiene rubber (SBR), isoprene rubber (IR), acrylonitrile-butadiene rubber (NB
Diene rubbers such as R) are preferably used. This is because a diene rubber can be used in combination with a thermoplastic resin to use a crosslinking agent that crosslinks the diene rubber but does not crosslink the thermoplastic resin.

In the present invention, the rubber compound is E
Most preferably, the PDM is set to 100%. EPDM
Since the main chain is composed of a saturated hydrocarbon and does not contain a double bond in the main chain, the molecular main chain hardly breaks even when exposed to an environment such as a high-concentration ozone atmosphere or light irradiation for a long time. Therefore, the weather resistance of a final product, for example, a roller can be improved. EPDM includes a non-oil-extended type EPDM comprising only a rubber component and an oil-extended type EPDM containing a confidential oil together with a rubber component. In the present invention, it is preferable to use an oil-extended type.

In addition, butyl rubber, BR, isoprene rubber, SBR, chloropropylene rubber (CR),
One or more selected from NR, acrylonitrile-butadiene rubber, acrylic rubber, and ethylene propylene rubber (EPR) may be blended. When EPDM and other rubber are blended, EPD in total rubber
The ratio of M is preferably at least 50% by weight, more preferably at least 80% by weight.

The weight ratio of the styrene-based thermoplastic elastomer: (B) in the above (A) is in the range of 95: 5 to 1:99. When the weight ratio goes out of 95: 5,
The effect of improving roller marks cannot be obtained. On the other hand, if the ratio is out of the range of 1:99, the mechanical strength of the roller is reduced, and the generation of abrasion powder may occur. The weight ratio is preferably 90:10 to 5:95, more preferably 80: 2.
0 to 15:85. The optimum ratio can be appropriately selected depending on the purpose of use and other components used.

The polar-non-polar graft polymer in the above (B) is based on the total weight of the polymer in the above mixture (excluding the softener, the crosslinking agent, the filler, the processing aid, the zinc white, etc.).
The range is from 3% by weight to 15% by weight. polarity-
If the amount of the non-polar graft polymer is less than 3% by weight based on the total polymer weight, there is a problem that the polarity is insufficient and generation of roller marks cannot be suppressed. If the amount is more than 15% by weight, the thermoplastic elastomer is used. There is a problem that the whole composition becomes brittle and is unsuitable as a roller. The polymer referred to here is EPDM, SEEPS, SEPS,
Refers to a polar-non-polar graft polymer, PP and the like.

As the dynamic crosslinking agent, a resin crosslinking agent is preferably used. The resin cross-linking agent is a synthetic resin that causes a cross-linking reaction of the rubber by heating or the like, and is preferable because the problem of bloom that occurs when sulfur and a vulcanization accelerator are used in combination does not occur. In particular, when a phenol resin is used as the resin crosslinking agent, the paper feeding performance can be improved.

Other resin crosslinking agents include melamine
Examples thereof include formaldehyde resin, triazine / formaldehyde condensate, hexamethoxymethyl / melamine resin, and the above-mentioned phenol resin is particularly preferable. Specific examples of the phenol resin include various phenol resins synthesized by a reaction of a phenol such as phenol, alkylphenol, cresol, xylenol, and resorcin with an aldehyde such as formaldehyde, acetaldehyde, and furfural. In particular, an alkylphenol / formaldehyde resin obtained by reacting an alkylphenol having an alkyl group bonded to the ortho-position or para-position of benzene with formaldehyde has excellent compatibility with rubber, is rich in reactivity, and has a long crosslinking reaction start time. Is preferable because it can be performed relatively quickly. The alkyl group of the alkylphenol / formaldehyde resin is usually an alkyl group having 1 to 10 carbon atoms, and specific examples include a methyl group, an ethyl group, a propyl group, and a butyl group. Further, a modified alkylphenol resin obtained by addition-condensation of sulfurized-p-tert-butylphenol and an aldehyde, or an alkylphenol / sulfide resin can also be used as a resin crosslinking agent. The compounding amount of the resin crosslinking agent is preferably from 1% by weight to 50% by weight, particularly preferably from 8% by weight to 15% by weight, based on 100% by weight of rubber.

In the present invention, the dynamic crosslinking includes chlorine, bromine,
The reaction may be performed in the presence of halogen such as fluorine and iodine.
In order to allow halogen to be present during dynamic crosslinking, a halogenated resin crosslinking agent may be used, or a halogen-donating substance may be blended in the elastomer composition. Examples of the halogenated resin crosslinking agent include those obtained by halogenating each of the above addition condensation type resins. Above all, halogenated phenolic resins in which at least one halogen atom is bonded to the aldehyde unit of the phenolic resin, particularly halogenated alkylphenol formaldehyde resins, have excellent compatibility with rubber, are highly reactive, and have a high crosslinking reaction time. Is preferable because it can be performed relatively quickly.

Examples of the halogen-donating substance include tin chloride such as stannic chloride, ferric chloride, and cupric chloride. Examples of the halogenated resin include chlorinated polyethylene. These halogen donors may be used alone or in combination of two or more.

A crosslinking activator may be used in order to properly carry out the crosslinking reaction. Metal oxides are used as the crosslinking activator, and zinc oxide and zinc carbonate are particularly preferred.

The thermoplastic elastomer composition of the present invention may optionally contain a filler in order to improve the mechanical strength. As the filler, for example,
Examples of the powder include silica, carbon black, clay, talc, calcium carbonate, and titanium oxide. When a filler is compounded, it is preferable that the filler be 30% by weight or less based on 100% by weight of rubber. If the proportion of the filler exceeds the above range, the flexibility of the rubber may be reduced.

Further, the thermoplastic elastomer composition includes:
Further, an antioxidant, a wax and the like can be blended. Examples of anti-aging agents include, for example, imidazoles such as 2-mercaptobenzimidazole and phenyl-α-
Amines such as naphthylamine, N, N'-di-6-naphthyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, di-t-butyl-p-cresol, styrenated phenol and the like Phenols.

The above-mentioned thermoplastic elastomer composition of the present invention has durability, elasticity and flexibility, is excellent in moldability, and has good affinity with a polar recording liquid. Widely available. In particular, it is necessary to pick up and separate thin paper or film and feed paper while taking advantage of the above-mentioned excellent characteristics. Ink-feed printers, laser printers, electrostatic copiers, plain paper facsimile machines, ATM, etc. It is suitable as a rubber roller for printing, and has a good affinity for a recording liquid, especially a polar recording liquid, so that it can be used favorably in a high-quality ink jet printer.

Accordingly, the present invention provides a rubber roller characterized in that the polymer composition containing the thermoplastic elastomer composition is formed into a roller shape.

The rubber roller of the present invention can be manufactured, for example, by the following method. After the thermoplastic elastomer composition is swollen in the softener, the olefin resin-based pellets are mixed, kneaded, and extruded into pellets. The pellets, rubber, resin cross-linking agent, and other compounding agents are put into a rubber kneading device such as a twin-screw extruder, open roll, Banbury mixer, kneader, and the like, and heated to 160 to 220 ° C. for about 1 to 20 minutes. After kneading and dynamic vulcanization, the mixture is extruded from a rubber kneading device. The extruded rubber composition is formed into a pellet, and is used as an injection molding machine (injection molding machine).
Into a tube. After polishing the surface of this molded product, it is possible to cut it into required dimensions to obtain a rubber roller. Note that, instead of the injection molding machine, a rubber roller can be formed by extruding into a tube shape by a single screw extruder for resin and cutting the same. In the case of extrusion, in particular, the composition of the present invention is excellent in moldability and flowability. Therefore, by extruding and cutting at high speed, productivity can be greatly improved.

The hardness of the rubber roller is generally from 15 to 45 as measured by a JIS6301 type A hardness type.
Preferably, it is in the range of 20 to 40. Within this range, even if the rubber roller is pressed against paper or film with a relatively small pressing force, the rubber roller is sufficiently deformed, and a large contact area with paper or film can be obtained.

The rubber roller is formed in a cylindrical shape and has a thickness of 0.5 mm to 8 mm, preferably 1 mm to 5 m.
m. This depends on the strength of the rubber roller, but if the thickness is too small, it is difficult to form a large contact area with the paper even if the rubber roller is deformed. on the other hand,
If the thickness is too large, the pressing force of the rubber roller against the paper must be increased in order to deform the roller, and the mechanism for pressing the rubber roller against the paper increases in size.

[0039]

Embodiments of the present invention will be described below. The paper feed rubber roller of the present invention is formed into a cylindrical roller from a thermoplastic elastomer comprising the following composition,
The shaft center is pressed into the hollow portion, or both are fixed by bonding with an adhesive.

The thermoplastic elastomer composition comprises: (A) a high-molecular-weight styrene-based thermoplastic elastomer having a number average molecular weight of 80,000 or more, and, if necessary, a terminal having a number average molecular weight of 10,000 to 70,000. Unmodified low molecular weight styrene-based thermoplastic elastomer (B) Polymer composed of a polar terminal-modified thermoplastic elastomer and / or a polar-non-polar graft polymer (C) Rubber compound mainly composed of diene rubber such as EPDM (D ) A resin composition containing an olefin-based resin as a main component. (E) A softener. (F) A rubber composition containing a resin cross-linking agent (and a cross-linking accelerator). The rubber is dynamically cross-linked by a resin cross-linking agent. Rubber is dispersed in a mixture of a hydrogenated styrene-based thermoplastic elastomer and an olefin-based resin.

SEEPS is used for the high-molecular-weight hydrogenated styrene-based thermoplastic elastomer (A) and SEPS is used for the low-molecular-weight hydrogenated styrene-based thermoplastic elastomer. As an elastomer, one end hydroxyl group-modified SEEPS
As a polymer comprising a polar-non-polar graft polymer, polyethylene oxide graft polyethylene, polypropylene as an olefin resin (D), and EP as a rubber compound (C).
DM was used, a phenolic resin crosslinking agent was used as the resin crosslinking agent (F), and zinc oxide was used as the crosslinking activator. Furthermore, paraffin oil is used as a softening agent (E) to be blended for the purpose of adjusting hardness and the like.

(Examples) Examples 1 to 7 and Comparative Examples 1 to
With respect to No. 5, a thermoplastic elastomer composition having the composition shown in Tables 1 and 2 below was prepared, and the product was extruded into a roller shape (circular tubular shape), cut, fitted into a shaft core, and then fitted with a rubber roller. Was manufactured.

[0043]

[Table 1]

[0044]

[Table 2]

The numerical values in the table are% by weight. The abbreviation T
PE represents a thermoplastic elastomer. The materials used are as follows. EPDM (rubber): ESPRENE 670F manufactured by Sumitomo Chemical
(Paraffin oil (PW-380) 100% oil exhibition) High molecular weight hydrogenated styrene-based TPE: SEEPS (Mn = 300,000),
Kuraray's Septon 4077 low molecular weight hydrogenated styrene-based TPE: SEPS (Mn = 51,000),
Septon 2002, polar terminal-modified hydrogenated styrene-based TPE: SEEPS (Mn = 54,000, Mw = 60,000) at one end, Kuraray, Septon
HG252 Polar-non-polar graft polymer (polar-non-polar graft compound): polyethylene oxide grafted polyethylene, Sumitomo Chemical Sumigard 300G Olefin resin: polypropylene, Nippon Polychem,
Novatec PP BC6 Softener 1: Paraffin oil (non-polar oil), manufactured by Idemitsu Kosan, Diana Process Oil PW-380 Softener 2: Maleic acid-modified paraffin oil (polar oil), manufactured by Mitsui Chemicals, Lucant A-6002 Crosslinking activator : Zinc oxide, manufactured by Mitsui Kinzoku Mining Co., Ltd., zinc oxide 2
Species Resin cross-linking agent 1: Taoka Chemical's Tacchiroll 250-III Resin cross-linking agent 2: Taoka Chemical's Tacchiroll 201

The rubber roller was manufactured as follows.
After the thermoplastic elastomer composition is swollen in a softener, it is mixed with an olefin resin-based pellet by a twin-screw extruder, a kneader or a Banbury mixer or the like.
Kneading at a temperature of from 0 ° C. to 220 ° C. for 1 to 20 minutes to produce pellets comprising a mixture (compound) of a thermoplastic elastomer composition, an olefin resin, and a softener,
Thereafter, the pellets and necessary additives such as rubber, a reactive phenol resin as a resin crosslinking agent, a crosslinking activator, zinc white, an antioxidant and a filler are added to a twin screw extruder HTM3.
8 (manufactured by IBEC Co., Ltd.)
The rubber was dynamically crosslinked by kneading for 1 to 20 minutes while heating at a temperature of ° C, and then extruded. Next, the extruded kneaded rubber composition was pelletized, and the pellet was formed into a tube by an extruder. After that, cut and
A rubber roller having an outer diameter of 30 mm, an inner diameter of 25 mm, and a width of 15 mm was produced.

Examples 1 to 7 In each of Examples 1 to 7, the following components were mixed at the compounding ratio shown in Table 1, and the rubber in the mixture was dynamically crosslinked to obtain a uniform mixture. Was dispersed. (A) a high-molecular-weight styrene-based thermoplastic elastomer having a number-average molecular weight of 80,000 or more, and if necessary, a terminal-unmodified low-molecular-weight styrene-based thermoplastic elastomer having a number-average molecular weight of 10,000 to 70,000, (B) a polymer comprising a polar end-modified thermoplastic elastomer and / or a polar-nonpolar graft polymer,
(C) Rubber compound mainly composed of diene rubber such as EPDM (D) Olefin resin, (E) Softener (F) Resin cross-linking agent, Cross-linking activator

[Comparative Examples 1 to 5] On the other hand, as shown in Table 2, Comparative Examples 1 to 5
The mixing ratios other than the resin crosslinking agent and the crosslinking activator were changed respectively.

Comparative Example 1 A high molecular weight hydrogenated styrene-based TPE was added, and paraffin oil was used as a softening agent. The low molecular weight styrene-based thermoplastic elastomer having the number average molecular weight of the component (B) and the component (A) of 10,000 to 70,000 was not used for both the terminal-modified product and the unmodified product. (Comparative Example 2) A polar terminal-modified hydrogenated styrene-based TPE was added, and a paraffin oil was added as a softening agent. No high molecular weight styrene-based TPE having a number average molecular weight of 80,000 or more was added. (Comparative Example 3) High molecular weight hydrogenated styrene-based TP of (A)
E, a polar-non-polar graft polymer (polar-non-polar graft compound) of (B), and paraffin oil as a softener of (E) were added. However, the content of the polar-non-polar graft polymer (polar-non-polar graft compound) was set to 17.5% by weight or more in a specified range or more. Comparative Example 4 Maleic acid-modified paraffin oil (polar oil) was used as a softening agent other than that contained in the oil-extended rubber (Esprene 670F). The component (B) was not added. (Comparative Example 5) High molecular weight hydrogenated styrene-based TP of (A)
E and low molecular weight terminal unmodified hydrogenated styrene-based TPE were added, and maleic acid-modified paraffin oil (polar oil) was added as a softening agent other than that contained in the oil-extended rubber (Esprene 670F). The component (B) was not added.

The rubber rollers of Examples 1 to 7 and Comparative Examples 1 to 5 were tested and evaluated for generation of abrasion powder (durability test) and presence or absence of roller marks. The evaluation results are shown in Tables 1 and 2 described above.

(Durability Test) The presence or absence of wear powder was tested by the following method. Actual machine (Seiko Epson PM-
The paper feed roller composed of the rubber roller of the example and the comparative example is attached to the 770C machine), plain paper (P paper (PPC paper) manufactured by Fuji Xerox Co., Ltd.) is set in the feeder, and a plain print command is repeatedly sent. After printing 5,000 sheets, a special inkjet recording paper (Seiko Epson Super Fine glossy paper MJA4SP3)
The paper was passed through to count the number of abrasion powders adhering to the paper. Then, the average value of the two paper feed rollers was calculated.
The following four-stage evaluation was performed based on the average value of the worn powder.

A: Very good. The number of wear powders (average) is 2 or less. ：: good. The number (average) of wear powder is more than 2 and less than 6. Δ: Possible. The number (average) of wear powder is 6 or more and less than 10. ×: Not possible. The number of wear powders (average) is 10 or more.

(Evaluation of Roller Marks) After the rubber rollers of the examples and comparative examples were cut to a width of 14.65 ± 0.15 mm,
After being washed and left at 60 ° C. for 2 hours, it was set on a Seiko Epson PM-770C machine. As the printing paper, glossy paper MJA4SP3 for exclusive use of Super Fine, also manufactured by Seiko Epson Corporation was used. With the rubber roller, printing paper, ink, etc. set, use the blue solid print command in the super fine image quality mode,
The printed image was evaluated on the following three scales. The ink used as the recording liquid is a polar aqueous ink (color ink cartridge IC5CL0, manufactured by Seiko Epson Corporation).
2W).

：: No roller mark. Δ: Slight roller marks are observed, but there is no practical problem unless it is a high-quality machine. ×: Roller marks were clearly recognized, and practical use was impossible.

The rubber roller of Comparative Example 1 containing only a high-molecular-weight, terminal-unmodified hydrogenated styrene-based TPE showed roller marks clearly and was not practical. In Comparative Example 2 using only the polar terminal-modified hydrogenated styrene-based TPE, the durability was deteriorated. In Comparative Example 3 in which the content of the polymer composed of the polar-nonpolar graft polymer was large, the durability was deteriorated,
Roller marks were clearly recognized, and it was not practical. In Comparative Example 4 in which a polar oil was used as a softening agent, roller marks were clearly observed, and the sample was not practical. If polar oil is added to non-polar rubber or resin, oil and rubber,
It is considered that the compatibility with the resin deteriorated. In Comparative Example 5 in which a mixed elastomer of a high-molecular-weight hydrogenated styrene-based TPE and a low-molecular-weight hydrogenated styrene-based TPE and a polar oil were added as a softening agent, roller marks were clearly observed as in Comparative Example 4, making it impractical. Met.

On the other hand, the high molecular weight hydrogenated styrene TPE of the component (A) and the polar terminal-modified hydrogenated styrene TPE
And the weight ratio of (A) :( B) is about 1: 3. The rubber roller of Example 1 is an excellent high-performance roller having excellent moldability, durability, and no roller marks. In addition, it was confirmed that the rubber rollers of the other Examples 2 to 7 were also sufficiently practical and excellent.

[0057]

As is clear from the above description, according to the present invention, a thermoplastic elastomer composition obtained by dynamically cross-linking a rubber with a cross-linking agent and dispersing the rubber in a styrene-based thermoplastic elastomer has a high molecular weight. A styrene-based thermoplastic elastomer, if necessary, a thermoplastic elastomer containing a low-molecular-weight styrene-based thermoplastic elastomer, a polymer composed of a polar terminal-modified thermoplastic elastomer and / or a polar-nonpolar graft polymer, and a softener, By using a combination of an olefin-based resin and a rubber containing EPDM as a main component, moldability is improved, and both flexibility and abrasion resistance / durability can be secured.
Good compatibility with polar recording liquids such as aqueous inks.

As an example of a molded product of the thermoplastic elastomer composition of the present invention, a rubber roller for feeding paper is extremely suitable for an injection printer or the like which needs to pick up and transport a conveyed material such as paper or film and feed the paper while separating it. It is useful, and even when printing on super fine glossy paper, photo print paper or color OHP paper in a high quality printer, a good image can be obtained without leaving any roller marks.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/10 C08L 23/00 C08L 23/00 23/16 23/16 51/08 51/08 61/00 61/00 91/00 91/00 B41J 3/04 101Z (72) Inventor Yoshihisa Mizumoto 3-6-9, Wakihama-cho, Chuo-ku, Kobe-shi, Hyogo Sumitomo Rubber Industries, Ltd. (72) Inventor Hideyuki Okuyama Hyogo 3-6-9 Wakihama-cho, Chuo-ku, Kobe, Japan F-term (reference) in Sumitomo Rubber Industries, Ltd. 2C056 EA07 HA28 HA32 4F070 AA08 AA13 AA15 AA40 AA52 AB01 AB08 AB09 AB11 AB16 AC43 AC85 AC86 AC94 AE02 AE08 EA04 GA08 GB09 GC03 4F07 AA12X AA15 AA15X AA20 AA28X AA32X AA33X AA41 AA51 AA71 AA75 AA77 AA78 AC10 AE04 AH16 AH17 BA01 BB05 BC05 4J002 AE05Z BB035 BB065 BB075 BB085 BB01 CCBCC BB015 BB015 BB035 BB015 CC0 EH146 FD010 FD02Z FD025 FD026 FD030 GM00

Claims (6)

[Claims] 1. A thermoplastic elastomer composition (A) containing a high molecular weight styrene-based thermoplastic elastomer having a number average molecular weight of 80,000 or more, and a polar terminal-modified thermoplastic elastomer and / or a polar-nonpolar graft polymer. The composition (B) is mixed with a rubber compound (C) containing EPDM as a main component, and the rubber in the mixture is dynamically crosslinked and dispersed in the thermoplastic elastomer. Thermoplastic elastomer composition. 2. The thermoplastic elastomer composition (A)
The rubber compound (C) contains 600% by weight or less of oil with respect to 100% by weight of rubber, and contains an unmodified low molecular weight styrene-based thermoplastic elastomer having a number average molecular weight of 70,000 or less. A mixture of the above (A), (B) and (C), and a resin composition (D) containing 50% by weight or less of an olefin resin as a main component relative to 100% by weight of rubber of the rubber compound (C). The thermoplastic elastomer composition according to claim 1, comprising a softener (E) in an amount of 500% by weight or less based on 100% by weight of the rubber of the rubber compound (C), and a resin crosslinking agent (F). 3. The thermoplastic elastomer composition according to claim 1, wherein the weight ratio of the styrene-based thermoplastic elastomer in (A) :( B) is in the range of 95: 5 to 1:99. object. 4. The polar-non-polar graft polymer in (B) is 100% by weight of the total polymer in the mixture except for a softening agent, a crosslinking agent, a filler, a processing aid, zinc white, etc. The thermoplastic elastomer composition according to any one of claims 1 to 3, wherein the content of the thermoplastic elastomer is from 3% by weight to 15% by weight. 5. A rubber roller formed by molding the thermoplastic elastomer composition according to claim 1 into a roller shape. 6. The rubber roller according to claim 5, which is used as a paper feed roller for an ink jet printer.