JPH04174698A - Steering wheel - Google Patents

Abstract

PURPOSE:To prevent idle running without using a bonding agent, and also obtain an excellent soft feeling in the case of leather being wound, and make the work of leather winding smooth by getting rid of slidability, by forming a cover layer out of resin having the hardness of less than 45 at Shore A hardness. CONSTITUTION:A core material whose section is formed into a U-shape, and a cover layer that covers the outside of the core material, are equipped. The cover layer has at least two of a terminal polymer block A consisting of a number average molecular weight 5000-125000 aromatic mono-alkenyl or mono- alkenylidene hydro-carbon polymer. 100 parts by weight of a block co-polymer which is added with hydrogen selectively and consists of a structure having at least one of a middle polymer block B consisting of a number average molecular weight 10000-800000 partially or wholly hydrogen added aliphatic conjugate diene hydro-carbon polymer, is obtained.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a steering wheel.

The present invention relates to a steering wheel that is easy to operate and has a good grip feel.

<Conventional technology> Conventional steering wheel grips with a high-quality feel and good feel are typically made by coating the rim core mold with foamed polyurethane resin, but the molding cycle is long and the pin It has the disadvantage of being extremely expensive due to many factors such as the large number of defects caused by holes occurring in extremely important parts of the design, and the fact that it cannot be recycled. In addition, products coated with PVC resin had drawbacks such as bleeding, stickiness, slipping of the grip, and heavy weight due to the addition of a softening agent.

Under the above circumstances, there has been a problem in that it has been difficult to provide a steering wheel that is lightweight, soft, has good operability, and has a luxurious feel.

<Problems to be Solved by the Invention> The present invention attempts to solve the above-mentioned problems, and uses a U-shaped ring as the core material, preferably a resin having a Shore A hardness of 45 or less. It forms a coating layer to prevent slippage without using adhesives, and when the leather is wrapped, a very good soft feel is obtained. Furthermore, there is no slippage during the leather wrapping process, making it easy to wrap the leather. The purpose of this invention is to provide a steering wheel that is smooth and has good workability.

<Means for Solving the Problems> The present invention includes a core material formed in a U-shape and a synthetic resin coating layer covering the outside of the core material.

The coating layer.

(a) At least two terminal polymer blocks A each consisting of an aromatic monoalkenyl or monoalkenylidene hydrocarbon polymer having a number average molecular weight of 5,000 to 125,000.
and has a number average molecular weight of 10,000 to 800,0
00 partially or fully hydrogenated aliphatic conjugated diene hydrocarbon polymer consisting of a structure having at least one intermediate polymer block B consisting of a partially or completely hydrogenated aliphatic conjugated diene hydrocarbon polymer
100 parts by weight of the block copolymer.

(b) Mooney viscosity at 100°C (ML, +, 100
'C) is 150 to 350 per 100 weight of olefin copolymer rubber, 20 to 150 of a mineral oil softener is added.
Oil-extended olefin copolymer rubber containing 50 to 4 parts by weight
00 parts by weight.

(c) 2 to 100 parts by weight of polyolefin resin.

(b) 50 to 350 parts by weight of a mineral oil softener, and.

(c) Antistatic agent for polyolefin 0.05-10
parts by weight, and the composition is formed by first adding a mixture of at least the entire amount of component (b) and a part or the entire amount of component (c) among components (b) to (c) to an organic permeate. A core material and a covering layer characterized by being a thermoplastic elastomer composition that is partially crosslinked by heat treatment in the presence of an oxide, and then blended with this partially crosslinked product, component (a), and the remaining components. This relates to a steering wheel that is integrally molded with.

The present invention further relates to a steering wheel in which the coating layer is wrapped with genuine leather or synthetic leather.

The present invention will be described in detail below.

First, the core material formed in a U-shape will be explained.

If the core material is composed of a conventional round pipe ring 7 (Fig. 3) or solid round ring 8 (Fig. 4), and the covering layer is made of soft synthetic resin, use adhesive etc. However, the coating layer may slip due to changes over time.

Therefore, when using soft resin for the coating layer.

By using a U-shaped ring 2 formed by bending a plate material (band plate) into a U-shape with several rollers as a core material (Fig. 2), the above-mentioned problem of idling can be prevented, and It is also possible to reduce the weight of the ring portion.

Next, the coating layer of the present invention will be explained in detail.

(i) The monomer constituting the aromatic monoalkenyl or monoalkenylidene hydrocarbon polymer block A of the hydrogenated block copolymer (a) used in the present invention is styrene, α-methylstyrene, or The monomer forming the aliphatic conjugated diene hydrocarbon polymer block B is butadiene or isoprene.

A typical example of such hydrogenated block copolymerization has a styrene-ethylene/butylene-styrene structure, and is called by the abbreviation 5EBS, and is manufactured by Shell Chemical Company in the United States as Kraton-G.
There is one commercially available under the trade name (KRATON-G).

(ii) Next, the olefin copolymer rubber used in the present invention is 2, for example, ethylene-propylene copolymer rubber, ethylene-propylene-nonconjugated diene rubber,
Ethylene-butene-nonconjugated diene rubber, propylene-
Like butadiene copolymer rubber, it is an amorphous random elastic copolymer rubber containing olefin as a main component. Among these.

Particularly preferred is ethylene-propylene non-conjugated diene rubber. As the non-conjugated diene, dicyclopentadiene, 1,
Examples include 4-hexadiene, cyclooctadiene, methylene norbornene, and ethylidene norbornene, with ethylidene norbornene being particularly preferred.

As a more specific example, the propylene content is 10 to 5
Ethylene-propylene-ethylidene norbornene copolymer rubber (hereinafter referred to as r
It's called EPDMJ. ), and its 100°C Mooney viscosity (ML+, 100°C) is from 150 to 350, preferably from 170 to 300.

When the propylene content is less than 10% by weight, flexibility is lost, and when it is more than 55% by weight, mechanical properties are reduced. If the ethylidenenorbornene content is less than 1% by weight, the mechanical properties will deteriorate. If it is more than 30% by weight, the appearance of the steering wheel coating layer will deteriorate. Mooney viscosity at 100°C (MLl+41oo°C).

If it is lower than 150, the sticky feeling in the steering wheel coating layer will worsen.

However, the Mooney viscosity (ML, +4100°C) is 150
Using EPDM of ~350 improves the sticky feel and also improves the mechanical properties. Note that EPDM manufactured by a known method can be used.

(iii) Oil-extended olefin copolymer ``rubber'' of the present invention (
The mineral oil softener used in b) is a high-boiling petroleum distillate blended for the purpose of improving processability and mechanical properties, and includes paraffinic, naphthenic, or aromatic softeners. , paraffinic ones are particularly preferably used. If the amount of aromatic components increases, the staining property becomes stronger, which is not preferable.

(iv) In the present invention, the oil-extended olefin copolymer rubber (b) contains 20 to 150 parts by weight, preferably 30 to 120 parts by weight of a mineral oil softener per 100 parts by weight of the olefin copolymer rubber. It is something to do. If it is less than 20 parts by weight, it is necessary to add a large amount of mineral oil-based softener (d) in the next step in order to obtain a very flexible product with Shore A hardness of 45 or less, resulting in worsening of the sticky feeling. do. On the other hand, if the amount is more than 150 parts by weight, the plasticity increases significantly, and even after forming a partially crosslinked product, problems such as mutual adhesion occur, making handling difficult.

A known method is used for oil spreading of EPDM. For example, using equipment such as a roll or Pan Bali mixer,
Obtained by mechanically kneading PDM and a mineral oil softener to extend the oil, or by adding a predetermined amount of mineral oil softener to an EPDM solution and then removing the solvent by a method such as steam stripping. There are methods. Among these, a preferred oil extension method is a method using an EPDM solution, and E
It is easier to operate the PDM solution by using an EPDM solution obtained by polymerization.

(v) Polyolefin resin used in the present invention (
c) is polypropylene or propylene and carbon number 2
It is a copolymer with α-olefin or more. Specific examples of α-olefins having two or more carbon atoms include ethylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 1-decene, 3-methyl-1-pentene, Examples include 4-methyl-1-pentene and 1-octene.

The melt flow rate of these polymers is 0.1 to 100.
g/10 minutes, preferably in the range of 0.5 to 50 g/10 minutes. Even if the melt flow rate is smaller than 0.1 g/10 minutes, problems arise in moldability.

In addition, in a partially crosslinked product obtained by heat-treating part or all of the oil-extended olefin copolymer rubber (b) and polyolefin resin (c) of the present invention in the presence of an organic peroxide, the amount of the polyolefin resin (e) If it is less than 5% by weight, the fluidity will decrease and the appearance of the steering wheel coating layer will be poor.

(vi) An organic peroxide for partially crosslinking a mixture consisting of part or all of the oil-extended olefin copolymer rubber (b) and the polyolefin resin (c).

2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane-3,1,3-bis-(t -butylperoxyisopropylene)benzene, 1,1-di(t-butylperoxy)3.5.5-)limethylcyclohexane, 2,5-dimethyl-2,5-di(peroxybenzoyl)hexyne- 3. Dicumyl peroxide, etc.

Among these, 2°5-
Dimethyl-2,5-di(t-butylperoxy)hexane is preferred.

The amount of organic peroxide added is a total of 100% of the oil-extended olefin copolymer rubber (b) and polyolefin resin (c).
It can be selected within the range of 0.005 to 2.0 parts by weight, preferably 0.01 to 0.6 parts by weight. 0
．． If it is less than 0.05 parts by weight, the effect of the crosslinking reaction is small:,2
．． If it exceeds 0 parts by weight, it will be difficult to control the reaction and it will not be economically advantageous.

(f) In the present invention. When producing a partially crosslinked mixture of a part or all of the oil-extended olefin copolymer rubber (b) and the polyolefin resin (c), N,N-m-phenylene bismaleide, Toluylene bismaleimide, P-quinone dioxime, nitrobenzene, diphenylguanidine.

Peroxide crosslinking aids such as trimethylolpropane,
or divinylbenzene, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate 2
Polyfunctional vinyl monomers such as trimethylolpropane trimethacrylate and allyl methacrylate can be used. By blending such a compound, a homogeneous and mild crosslinking reaction and a reaction between the olefin copolymer rubber and the polyolefin resin occur, thereby making it possible to improve the mechanical properties.

The amount of peroxide crosslinking aid or polyfunctional vinyl monomer added is 10% of the mixture consisting of part or all of the oil-extended olefin copolymer rubber (b) and the polyolefin resin (c).
With respect to 0 parts by weight, it can be selected within the range of o, oi to 4.0 parts by weight. Preferably it is 0.05 to 2.0 parts by weight. If the amount is less than 0.01 part by weight, the effect is difficult to appear.

Exceeding 4.0 parts by weight is not economically advantageous.

(vffi) Oil-extended olefin copolymer rubber of the present invention (
b) and a part or all of the polyolefin resin (c), a hydrogenated block copolymer (a), a mineral oil softener (d), etc. The mineral oil-based softener (d) is a high-boiling petroleum distillate blended for the purpose of improving processability and mechanical properties, and includes paraffinic, naphthenic, or aromatic softeners. system is particularly preferably used. The more aromatic components there are, the more contaminating the product becomes.

Undesirable.

The mineral oil softener (d) may be the same as the mineral oil softener in the oil-extended olefin copolymer rubber (b), or may have a different viscosity.

(ix) Specific examples of the antistatic agent (e) for polyolefins added in the present invention include the following.

That is, (a) cationic compounds such as primary amine salts, tertiary amines, quaternary ammonium compounds, and pyridine derivatives.

(b) Sulfated oil 2 soap, sulfated ester oil, sulfated amide oil, olefin sulfate ester salts, fatty alcohol sulfate ester salts, alkyl sulfate ester salts, fatty acid ethyl sulfonates, alkylnaphthalene sulfonates,
Anionic products such as alkylbenzene sulfonates, succinic ester sulfonates, and phosphate ester salts.

(c) Partial fatty acid ester of polyhydric alcohol, ethylene oxide adduct of fatty alcohol, ethylene oxide adduct of fatty acid, ethylene oxide adduct of fatty amine or fatty acid amide, ethylene oxide adduct of alkylphenol, ethylene oxide of alkylnaphthol appendix.

Nonionic products such as ethylene oxide adducts of partial fatty acid esters of polyhydric alcohols and polyethylene glycol.

) Amphoteric compounds such as carboxylic acid derivatives and imidacillin derivatives.

Generally, non-ionic compounds, such as polyoxyethylene alkylamine, polyoxyethylene alkyl amide or their fatty acid esters, glycerin fatty acid esters, etc. are particularly preferred.

The above antistatic agent (c) may be a single type or a mixture of two or more types. Also, the amount added is 1
Hydrogenated block copolymer (a) of the present invention 100
It is added in an amount of about 0.05 to 10 parts by weight, preferably about 0.1 to 8 parts by weight.

If the addition ratio is higher than this, leaching will occur on one surface.

This is not preferable because it causes a decrease in physical properties. This antistatic agent (
By adding c), a steering wheel without a sticky feeling can be obtained.

In addition, adhesion of dust due to the elimination of sticky feeling, bleeding of softener, etc. is reduced, and the charging property, which is the original function of the antistatic agent, is reduced, and the adhesion of dust due to charging is also reduced.

(X) The thermoplastic elastomer composition that is the coating layer of the present invention contains an antioxidant and a weathering agent, if necessary.

Lubricant 2 Sub-materials such as colored pigments and inorganic fillers can be blended. However, blending a large amount of inorganic filler is not preferable because it impairs the advantage of the thermoplastic elastomer that is the coating layer being lighter than PVC resin and increases the weight of the steering wheel.

Next, integral molding of the core material and the covering layer will be explained.

The core metal assembly, in which the iron boss, spokes, U-shaped ring, etc. are integrally assembled by welding, is inserted into the mold of an injection molding machine, and the resin of the nine inventions is injected to form a coating layer.

In the present invention, the genuine leather to be wrapped on the soft resin coating layer is made of leather from adult cows, calves, etc.

Synthetic leather is a sheet made of urethane as the main material and a backing fabric laminated with leather-like ties on the surface.

These leathers or sheets are unrolled from the state they were wrapped around the steering wheel, then punched out as a jig, and sewn with polyester thread at the joint inside the grip.

<Example> An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the overall appearance of a steering wheel according to the present invention, in which 1 is a grip portion, 5 is a horn pad portion of the steering wheel, and 6 is an emblem portion.

FIG. 2 shows a sectional view taken along the line AA' in FIG. 1, and 2 is a U-shaped ring, although it is not visible in the grip in FIG. 3 is a soft synthetic resin which is a covering layer. Although it is not visible in Figure 1, there is a spoke part inside the horn pad part.

Further, two pieces of leather or synthetic leather 4 are provided on the upper side of the covering layer 3.

Figures 3 and 4 show views corresponding to the AA' cross-sectional view of the conventional example. FIG. 3 shows a sectional view of a grip portion of a conventional example, in which a pipe ring 7 is used. FIG. 4 also shows a sectional view of a grip portion of a conventional example, in which a solid ring 8 is used.

If such a structure is used and the covering layer is formed of a soft synthetic resin.

Even if an adhesive is used, the coating layer may slip due to changes over time. -Using the U-shaped ring that was used in the invention of powertrains prevented the problem of idling.

The coating layer 3 used had a composition similar to the following. That is, ■ Mooney viscosity (ML++4 ioo°C), 24
2. Propylene content: 28%, EPDM with an iodine value of 12
per 100 parts by weight of EPDM in a hexane solution of Idemitsu Kosan, Diana Process Oil P as a mineral oil softener.
100 parts by weight of W380 was added, and then the solvent was removed by steam stripping to create oil-extended EPDM.

200 parts by weight of this oil-extended EPDM and melt flowray)
(according to JIS K7210, 230℃) is 3g/1
0 min propylene-butene copolymer (butene content: 23
25 parts by weight (% by weight) and 2.5 parts by weight of N,N-metaphenylene bismaleimide were mixed in a Banbury mixer.
After kneading for 7 minutes at 70-200°C.

A pellet masterbatch was created using an extruder.

Next, 0.32 parts by weight of 2,5-dimethyl-2,5-di(tertiary-butylperoxy)hexane per 100 parts by weight of the masterbatch was uniformly blended using a Henschel mixer.

This blend was dynamically heat-treated at 250+10° C. for 70 seconds using a twin-screw kneader capable of producing strong mixing force.

■ For 100 parts by weight of a block copolymer having an A-B-A structure consisting of polystyrene block A with a number average molecular weight of 31,000 and fully hydrogenated butadiene block B with a number average molecular weight of 130,000, Heat treated product 26
Propylene-ethylene random copolymer (ethylene content: 4.7%) 0 parts by weight, melt flow rate 7 10
Using a Banbury mixer, 150 parts by weight of Idemitsu Kosan Diana Process Oil PW90150 as a mineral oil softener, 156 parts by weight of stearyl jetanolamine as an antistatic agent, and 0.78 parts by weight of stearic acid monoglyceride were mixed and kneaded using a Banbury mixer. I used the one I made. .

The Mooney viscosity (ML, +, 100°C) in (2) was calculated using the following formula for the viscosity of EPDM (MLI) in accordance with ASTM D-927-57T.

1°'(ME,')=0.0066 (APHR)M
LI, Viscosity ML2 of EPDM, Viscosity ΔPHR of oil-extended EPDM: Amount of oil extended per 100 parts by weight of EPDM The obtained steering wheel had a very good soft feel and good operability.

<Effects of the Invention> As described above, according to the present invention, it is lightweight, soft,
Moreover, it is possible to provide a steering wheel with good operability and a luxurious feel.

[Brief explanation of drawings]

FIG. 1 is a plan view of a steering wheel according to the invention. FIG. 2 is a sectional view taken along the line AA' in FIG. FIGS. 3 and 4 are views corresponding to a cross-sectional view taken along line AA' of a conventional steering wheel. The symbols in the figure are as follows. 1... Grip part 2... U-shaped ring 3... Coating layer 4... Leather tail... Horn pad part 6... ...Emblem part Figure 1 Figure 2 Figure 3

Claims (3)

[Claims] (1) A core material having a U-shaped cross section and a coating layer covering the outside of the core material, the coating layer having: (a) a number average molecular weight of 5,000 to 125,000; A partially or completely hydrogenated polymer having at least two terminal polymer blocks A consisting of an aromatic monoalkenyl or monoalkenylidene hydrocarbon polymer and having a number average molecular weight of 10,000 to 800,000. Selectively hydrogenated block copolymer 100 consisting of a structure having at least one intermediate polymer block B consisting of an aliphatic conjugated diene hydrocarbon polymer
Parts by weight, (b) Mooney viscosity at 100°C (ML_1_+_4100
℃) is 150 to 350 per 100 parts by weight of olefin copolymer rubber, 20 to 150 parts of mineral oil softener is added.
Oil-extended olefin copolymer rubber containing 50 to 4 parts by weight
00 parts by weight, (c) 2 to 100 parts by weight of a polyolefin resin, (d) 50 to 350 parts by weight of a mineral oil softener, and (e) 0.05 to 10 parts by weight of an antistatic agent for polyolefins. and the composition first comprises component (b).
-(e), a mixture of at least the entire amount of component (b) and a part or the entire amount of component (c) is heat-treated in the presence of an organic peroxide to partially crosslink it, and then this partially crosslinked product and the component A steering wheel characterized by being a thermoplastic elastomer composition formed by blending (a) and the remaining components. (2) The steering wheel according to claim 1, wherein the hardness of the coating layer is 45 or less in Shore A hardness based on ASTM-D-2240. (3) A steering wheel characterized in that the coating layer according to claim 1 or 2 is wrapped with genuine leather or synthetic leather.