JPS6397649A - Rubber roll for business machine - Google Patents

Abstract

PURPOSE:To provide the title rubber roll which does not cause bleedout and has excellent rubber elasticity from a thermoplastic elastomer material consisting of a specified hydrogenated block copolymer, a softener for non- aromatic rubbers and a polystyrene resin. CONSTITUTION:100pts.wt. hydrogenated block copolymer (A) obtd. by hydrogenating a block copolymer consisting of at least two polymer blocks A mainly composed of an arom. vinyl compd. (e.g., styrene) and at least one polymer block B mainly composed of a conjugated diene compd. (e.g., butadiene) is mixed with 20-300pts.wt. softener (B) for non-arom. rubbers (e.g., paraffinic process oil) and 20-300pts.wt. polystyrene resin (C) (e.g., polystyrene) to obtain a thermoplastic elastomer material. Part or the whole of the desired rubber roll for business machines is formed from said material.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a shim roll for office equipment made of a thermoplastic nidistomer material that does not bleed out and has excellent elasticity (compression set) and surface smoothness. Regarding.

[Conventional technology]

In recent years, office automation has progressed, and office equipment supplies,
For example, copy machines, computers, word processors,
Facsimile machines have become general-purpose office equipment. These office machines were created using advanced technology, and although they have been further improved, in order to keep good records, these office machines mechanically use rubber rolls in the paper feed section. , this shim roll has become an important part of office equipment.

Traditionally, these shim rolls have been made of vulcanized materials such as silicone gum, styrene/butadiene copolymer comb, polyphthalene copolymer comb, and ethylene/propylene copolymer comb.

However, these shim rolls made of vulcanized rubber are
Because large amounts of sulfur, vulcanization accelerators, vulcanization accelerators, mold release agents, softeners, various inorganic fillers, etc. are blended during manufacturing, long-term use may cause the blends to bleed out, causing adhesion to recording paper, etc. Paper feeding performance may deteriorate, or due to poor surface smoothness, paper feeding performance may deteriorate, or print distortion may occur.
At present, there are many problems such as insufficient image stability. For this reason, these are made of vulcanized rubber and run! Several proposals have been made for the purpose of improving the problems of muroll, among which, for example,
No. 8853 proposes a rubber roll molded from a thermoplastic elastomer made of a hydrogenated block copolymer having a specific structure, oil, and polyolefin resin. Compared to conventional rubber rolls made of vulcanized rubber, the rubber roll proposed here does not contain vulcanization compounding agents such as sulfur, so the treedness of the compounding agents has been improved.

(Problems to be Solved by the Invention) However, since the rubber roll obtained by this proposal uses polyolefin resin in combination, ethylene and butylene, which are the so-called soft segments of the hydrogenated block copolymer provided, are Due to the good compatibility between the copolymerized portion and the polyolefin resin, it has the disadvantage of substantially hardening this soft segment region, which limits the blending of the polyolefin resin to be added, resulting in poor surface smoothness of the rubber roll. The e-lance of hardness and rubber elasticity (compression set) was still insufficient, and therefore the print and image stability due to the 2 ml paper feed performance was insufficient.

The present invention was made in order to solve the problems that were difficult to solve with the conventionally known thermoplastic nidistomer compositions described above. This was made based on the desire for a rubber roll that improves the decrease in rubber elasticity (compression set) due to the increase in hardness of the composition due to the above-mentioned polyolefin resin blended, and has further excellent surface smoothness. This request was fully achieved by a thermoplastic nidistomer material consisting of a specific component that had not been previously known as a rubber roll forming material, resulting in a shim roll for office equipment with excellent surface smoothness and elasticity (compression set). This is what was discovered.

(Means for Solving Problems) That is, the present invention provides: (a) a polymer block A mainly composed of at least two vinyl aromatic compounds; a polymer block B mainly composed of at least one conjugated diene compound; Hydrogenated block copolymer obtained by hydrogenating a block copolymer consisting of 10011j@part (b) 20 to 300 parts by weight of a non-aromatic softener (c) 20 to 300 parts by weight of polystyrene resin The present invention provides a rubber roll for office equipment, which is partially or entirely constructed of a thermoplastic elastomer material comprising:

The present invention will be described in detail below.

The hydrogenated block copolymer used as the (&) component in the present invention is a polymer block A mainly composed of at least two vinyl aromatic compounds and a polymer mainly composed of at least one conjugated diene compound. It is obtained by hydrogenating a block copolymer consisting of block B, for example, A-B-A, B-A-B-A, (A-B-)1S
i, a hydrogenated vinyl aromatic compound-conjugated diene compound block copolymer having a structure such as A-B-A-B-A. This hydrogenated block copolymer is
Vinyl aromatic compound is 5 to 60 times, preferably 10 times
Containing ~50% by weight, and further referring to the block structure, polymer block A containing a vinyl aromatic compound as a living body contains a vinyl aromatic compound polymer block or a vinyl aromatic compound in an amount exceeding 50% by weight, preferably 70 il.
It has a structure of a copolymer block of a vinyl aromatic compound containing t% or more and a hydrogenated conjugated diene compound, and further includes a polymer block B mainly composed of a hydrogenated conjugated diene compound. , hydrogenated conjugated diene compound polymer block, or hydrogenated conjugated diene compound in an amount exceeding 50% by weight, preferably 70% by weight.
It has a structure of a copolymer block of a hydrogenated conjugated diene compound containing qb or more and a vinyl aromatic compound. In addition, the polymer block A mainly composed of these vinyl aromatic compounds and the polymer block B mainly composed of a hydrogenated conjugated diene compound are hydrogenated conjugated diene compounds in the molecular chains of each polymer block. Alternatively, the distribution of the vinyl aromatic compound may be random, highly birded (monomer component increases or decreases along the molecular chain), partially block-like, or any combination thereof, and the vinyl aromatic compound is When there are two or more polymer blocks each consisting mainly of a polymer block and the hydrogenated conjugated citric compound, each polymer block may have the same structure, It may have a different structure.

Examples of the vinyl aromatic compound constituting the hydrogenated block copolymer include styrene, α-methylstyrene, vinyltoluene, and p@a-butylstyrene. Alternatively, two or more types can be selected, and styrene is preferred among them. Further, as the conjugated diene compound before hydrogenation constituting the hydrogenated conjugated diene compound, for example, one or two types from butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylto-3-butadiene, etc. The above are selected, among which butadiene, isoprene and combinations thereof are preferred. The microstructure of a polymer block mainly composed of a conjugated diene compound before hydrogenation can be arbitrarily selected; for example, in a polybutadiene block, the 1,2-microstructure is 20
-50t4, preferably 25-45t4.

Further, the number average molecular weight of the hydrogenated block copolymer used in the present invention having the above structure is s, ooo to 1.000,
000, preferably io, ooo~soo, ooo
, more preferably in the range of 30.000 to soo, ooo, and the molecular weight distribution [ratio of weight average molecular weight (Mv) to number average molecular weight (Me) (My/mn)] is 1
It is less than or equal to 0. Furthermore, the molecular structure of the hydrogenated block copolymer may be linear, branched, radial, or any combination thereof.

These block copolymers may be produced by any method as long as they have the structure described above. For example,
3798, a vinyl aromatic compound-conjugated diene compound block copolymer is synthesized in an inert solvent using a lithium catalyst, and then the vinyl aromatic compound-conjugated diene compound block copolymer is synthesized using a lithium catalyst or the like. As a method for producing hydrogenated products of polymers, for example, Japanese Patent Publication No. 42
Although it can also be obtained by the method described in Japanese Patent Publication No. 8704 and Japanese Patent Publication No. 43-6636, titanium-based water exhibits particularly excellent weather resistance and heat deterioration resistance of the hydrogenated block copolymer obtained. Hydrogenated block copolymers synthesized using an added catalyst are most preferred, for example, as disclosed in JP-A-59-133
The hydrogenated block copolymer used in the present invention is synthesized by hydrogenation in the presence of a titanium-based hydrogenation catalyst in an inert solvent by the method described in JP-A No. 203 and JP-A-60-79005. can do. At that time, the aliphatic double bonds based on the conjugated diene compound of the vinyl aromatic compound-conjugated diene compound block copolymer are hydrogenated at least to the SOW, and the polymer block mainly composed of the conjugated diene compound is morphologically olefinic. The compound can be converted into a polymer block.

Further, hydrogenation of aromatic double bonds based on the vinyl aromatic compound copolymerized into the polymer block A1 mainly composed of a vinyl aromatic compound and, if necessary, the polymer block B mainly composed of a conjugated diene compound. Although there is no particular restriction on the hydrogenation rate, it is preferable that the hydrogenation rate is 20 inches or less. The amount of unhydrogenated aliphatic double bonds contained in the hydrogenated block copolymer can be easily determined using an infrared spectrophotometer, nuclear magnetic resonance apparatus, or the like.

Next, the non-aromatic shim softening agent used as component (b) in the present invention is an essential component for making the resulting composition into a flexible male gum-like composition. Mineral oil or liquid synthetic low molecular weight softeners are suitable.

Among these, mineral oil-based shim softeners, called process oils or extender oils, which are generally used to soften, increase volume, and improve processability of shims, are a mixture of aromatic rings, naphthenic rings, and paraffin chains. Those in which the number of carbon atoms in the paraffin chain accounts for 50 or more out of all carbons are called paraffin series, and those in which the number of carbon atoms in the naphthene term is 3
Those containing 0 to 45% are considered to be 7-tene, and those having more than 30 aromatic carbon atoms are considered to be aromatic. The mineral oil-based softening agent used as component (b) of the present invention is preferably one of the above-mentioned categories, 7-tene-based and tracheine-based, and aromatic-based softeners having an aromatic carbon number of 30 or more are The composition with the component ta+ is unfavorable in terms of dispersibility and solubility. These non-aromatic systems! The properties of the softener for rubber include a kinematic viscosity of 20 to 500 cst at 37.8°C.
.

Pour point is -10~-15℃ and flash point is 170~30
Indicates 0°C. As the synthetic softener, polybutene, low molecular weight polybutadiene, etc. can be used, but the mineral oil-based softener for rubber gives better results.

The amount of the softener (b) is 20 to 300 parts by weight per 100 parts by weight of the component (-), preferably 30 parts by weight.
~200 parts by weight. If the amount exceeds 30Q]i parts, the softener tends to bleed out, and the final product may become sticky, and its mechanical properties will also deteriorate. In addition, when the content is less than 20 parts by weight,
The resulting composition slows down to a resin composition, increases hardness,
In addition to losing flexibility, this is also unfavorable from an economic point of view.

Next, the polystyrene resin used as component (C) of the present invention is used to improve processability during molding and to adjust the hardness of the resulting rubber roll. Compared to the rubber roll blended with the additive block copolymer, more polystyrene resin is added to obtain a rubber roll with the same hardness than when only polyolefin resin is added, in order to give a rubber roll with lower hardness than the same amount of polyolefin added. It becomes possible to add resin, and as a result, a rubber roll with excellent surface smoothness can be provided.

As the polystyrene resin provided here, those obtained by known radical polymerization methods and ionic polymerization methods can be suitably used.
Its number average molecular weight is s, ooo~soo, ooo,
Preferably, it can be selected from the range of io, ooo to 200.000, and the molecular weight distribution [ratio of weight average molecular weight (My) to number average molecular t (Mn) (M-72n>) is preferably 5 or less. Specifically, for example, polystyrene, polystyrene reinforced with polystyrene, polyα-methylstyrene, $p-113i styrene, and styrene-containing! Examples include styrene-butadiene block copolymers containing 60% by weight or more, and two or more types of these may be used. Similarly, a copolymer obtained by polymerizing a mixture of monomers constituting these polymers may also be used.

The amount of component (c) mentioned above can be suitably selected in the range of 20 to 300 parts by weight, especially 30 to 150 parts by weight, based on 100 parts by weight of the hydrogenated block copolymer of component (a).
Parts by weight are preferred. If the amount exceeds 300 parts by weight, the hardness of the resulting rubber roll will become too high and the rubber elasticity (compression set) will deteriorate, which is not preferable. If the amount is less than 20i-i parts, the resulting rubber roll will have good rubber elasticity, but the processability during molding 2 and surface smoothness will deteriorate, which is not preferable.

(a) to (c) that can be provided for the present invention listed above
) In addition to the components, an inorganic filler and a polyolefin resin can be added as necessary.

The inorganic filler, which can be added as needed, not only has the benefit of reducing product costs as a filler, but also has the benefit of having a positive effect on quality improvement (compression set, elongation). The amount added varies depending on the need, but the ingredients (
a) 300 parts by weight or less, preferably 20 to 250 parts by weight per 100 parts. Examples of inorganic fillers include calcium carbonate, carmen black, talc, clay, magnesium hydroxide, mica, norium sulfate, natural silicic acid, synthetic silicic acid (white carmen), and titanium oxide. Channel black, furnace black, etc. can be used.

Among these inorganic fillers, talc, calcium carbonate and 7 Arnes Black are economically advantageous and preferred. It is also possible to add a conductive filler to impart conductivity; for example, conductive carmen such as Ketjenblack may be used.

Furthermore, polyolefin resins, which can be added as needed, are effective in adjusting the hardness, improving molding processability, and heat resistance of the resulting rubber roll, such as polyethylene, ultra-high molecular weight high-density ethylene, isotactic polypropylene, etc. , copolymers of propylene and small amounts of other α-olefins, such as propylene-ethylene copolymers, propylene-1-hexene copolymers, propylene-4-methyl-1
Examples include pentene copolymers, poly-4-methyl-1-pentene, polybutene-1, and the like. MFR (ASTM-
D-1238-L conditions, 230°C) is 0.1 to 50 g/
10 minutes, particularly in the range of 0.5 to 30 g/10 minutes.

The rubber roll of the present invention can be molded from a thermoplastic elastomer that is a composite of each of the above-mentioned components, but if necessary, flame retardants, glass fibers, carzene rut fibers, antioxidants, heat-resistant stabilizers, ultraviolet absorbers, hindered amines, etc. A light stabilizer, a coloring agent, etc. can be added.

(a) to (c) that can be provided to the rubber roll of the present invention
) As a method for compounding a thermoplastic elastomer mainly composed of components, methods used in the production of ordinary resin compositions or in the production of composite materials can be adopted. ζ Lee mixer, heating roll,
Blinder 1 Can be combined using a melting mixer such as various kneaders. At this time, there is no restriction on the order in which each component is added; for example, all the components may be premixed using a mixer such as a Henschel mixer or blender, and then melted and compounded using the above-mentioned mixer, or any components may be premixed and a master nozzle may be added. An addition method can be adopted in which the components are melted and composited, and then the remaining components are added and the remaining components are melted and composited.

〔Effect of the invention〕

The TM roll of the present invention has excellent TM elasticity (compression set) and surface smoothness, so it can be used in various office equipment,
For example, it provides excellent performance in recording paper feeding performance, printing, and image stability in copying machines, computers, facsimile machines, word processors, etc., and there is no bleed-out of compounds found in vulcanized rubber.

〔Example〕

The present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

In addition, in these Examples and Comparative Examples, the test methods used for various evaluations are as follows.

(1) Hardness [-] JIS-6301. A type (21 tensile strength (h/i) and elongation [ch] JIS-6301, a 2-inch thick injection sheet was used as the sample, and a 3-odd shape dumbbell was used as the test piece.

(3) Compression set [chi] JIS-6301.25 degrees deformation for 22 hours at 70°C (4) Surface smoothness JIS-B 6501, measured using a surface roughness meter (5) Extrusion processability A piece of rubber having an inner diameter of 12W and an outer diameter of 26cm was extrusion molded at 200°C using a 90cm diameter single-screw extruder, and the roughness of the surface of the pipe-shaped rubber roll component, the presence or absence of surging, etc. were comprehensively evaluated.

(6) Dimensional Accuracy The cylindricity of the pipe obtained in item (5) above was measured at both ends and the center using a laser micrometer, and those with a deviation of 9/9 within 3/100 were accepted.

) Bleed-out presence or absence (2) The injection sheet of 2cm thick obtained in section
After leaving it in a gear oven at ℃ for 2 hours, cool it to room temperature.
The presence or absence of bleed-out of the formulation from the sheet was determined.

In addition, the blended components are as follows.

(1) <Component (a-1)> Has a structure of hydrogenated polybutadiene-polystyrene-hydrogenated polybutadiene-polystyrene,
30% bound styrene, number average molecular weight 179. Goo
, molecular weight distribution 1.05, 1.05 of polybutadiene before hydrogenation.
A hydrogenated block copolymer having a 2-vinyl bond content of 41 units and a hydrogenation rate of 99 units was synthesized using a T1 hydrogenation catalyst described in JP-A-60-79005, and the component (a-1 ).

Structure f+(a-2)> It has a structure of polystyrene-hydrogenated polybutadiene-polystyrene, the amount of bound styrene is 23, and the number average molecule? , 193, OOO1 molecular weight distribution 1.06 The 1,2-vinyl bond amount of polybutadiene before hydrogenation is 34 units,
A hydrogenated block copolymer with a hydrogenation rate of 98% was produced in JP-A-59-1.
Component (a-2) was synthesized using the Ti-based hydrogenation catalyst described in Japanese Patent No. 33203.

<Component (a-a)> (Polystyrene-hydrogenated polybutadiene + TS
It has the structure i, the amount of bound styrene is 19, the number average molecular weight is 219,000, the molecular weight distribution is 1.37, the amount of 1,2-vinyl bonds in polybutadiene before hydrogenation is 43, and the hydrogenation rate is 99.
The hydrogenated block copolymer of H was synthesized using a Ti-based hydrogenation catalyst described in JP-A-59-133203, and was used as component (a-3).

<Component (a-4)> KRA having a polystyrene-hydrogenated polybutadiene-polystyrene structure and a bound styrene content of 33-
TON-G1651 (manufactured by Shell Chemical Company) (a-
4) As a component.

(2) Component (b) Diana Process Oil PW-380 manufactured by Idemitsu Kosan Co., Ltd.
[) Rough-in process oil, kinematic viscosity +381.6
cst (40°C), 30.1 est (I Q QC
), average molecule t746, ring analysis value; C^=0chi, CN=
27%, Cp = 73 thi] (3) Component (c) Styron 6ssr manufactured by Asahi Kasei Co., Ltd./Restyrene resin, VF
RtG)=s g/l o min] Examples 1 to 6. Comparative example 1
~3 Mix each component shown in Table 1 with a Henschel mixer,
The mixture was melt-kneaded in a diameter twin screw extruder at 220°C to obtain thermoplastic nidistomer pellets with good surface texture.

This material was injection molded to create a sheet sample for physical properties.
Furthermore, extrusion molding was performed to create a pipe-shaped pimlole part. Various evaluations were performed and the results are listed in Table 1. In addition,
In the comparative example, polypropylene (Asahi Polypro M-1300s manufactured by Asahi Kasei Corporation) was used instead of polystyrene as the component (c).

These results revealed that the male roll parts obtained using the thermoplastic nidistomer material of the present invention are excellent in BIM elasticity (compression set) and surface smoothness. On the other hand, the comparative example using polypropylene has hardness, rubber elasticity (
(compression set) and poor surface smoothness.

(Margin below)

Claims (1)

[Claims] (1) (a) Hydrogenating a block copolymer consisting of a polymer block A mainly composed of at least two vinyl aromatic compounds and a polymer block B mainly composed of at least one conjugated diene compound. 100 parts by weight of hydrogenated block copolymer (b) 20 to 300 parts by weight of non-aromatic rubber softener (c) 20 to 300 parts by weight of polystyrene. A rubber roll for office equipment characterized by