JP2000063592A - Automotive exterior material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automotive exterior material having excellent environmental deterioration resistance, abrasion resistance, durability and mechanical strength and having excellent touch (softness). SOLUTION: This automotive exterior material comprises a partially or perfectly cross-linked composition comprising (A) 1-99 pts.wt. of an ethylene.α- olefin copolymer produced from ethylene and a 6-12C α-olefin in the presence of a metallocene-based catalyst and (B) 1-99 pts.wt. of a propylenic resin, wherein the total amount of the components A and B is 100 pts.wt.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle exterior material. More specifically, the present invention relates to an automotive exterior material having excellent resistance to environmental degradation, abrasion resistance, durability, and mechanical strength, and excellent in tactile sensation (flexibility). [0002] Conventionally, bumpers, louver protectors and the like have been widely used as automotive exterior materials. However, a soft exterior material has a soft and good feel but a low mechanical strength, while a hard exterior material has
Tactile sensation (flexibility) is insufficient, which is problematic. Therefore, in addition to the above properties, environmental degradation resistance, wear resistance,
Also, the appearance of automotive exterior materials satisfying durability is expected. On the other hand, specific ethylene-propylene copolymers, ethylene-octene copolymers, and talc calanal polyolefin compositions for automobile exteriors (JP-A-10-13)
No. 9959). Since the materials disclosed in the above publications are not crosslinked, they have poor abrasion resistance or durability, especially compression set (C-Set), and the industry demands automotive exterior materials that can withstand practical use. [0004] In view of the above situation, the present invention does not have the above-mentioned problems, that is, it has an environmental degradation resistance, abrasion resistance, durability and mechanical strength. It is another object of the present invention to provide an automotive exterior material having excellent tactile sensation (flexibility). The present inventors have conducted intensive studies on automotive exterior materials having excellent tactile sensation (flexibility), environmental degradation resistance, durability and mechanical strength. Surprisingly, by using an olefin-based elastomer having a specific structure consisting of olefin as an essential component, while maintaining environmental degradation resistance and tactile sensation (flexibility), abrasion resistance, durability and The inventors have found that the mechanical strength is dramatically improved, and have completed the present invention. That is, the present invention relates to (A) ethylene and a compound having 6 carbon atoms.
Ethylene-α-olefin copolymer 1 comprising α-olefins Nos. 1 to 12 and produced using a metallocene catalyst
-99 parts by weight and (B) propylene-based resin 1 to 99 parts by weight [the total amount of (A) and (B) is 100 parts by weight]. Is provided. Hereinafter, the present invention will be described in detail. The automotive exterior material of the present invention is obtained by molding a partially or completely crosslinked composition comprising (A) a specific ethylene / α-olefin copolymer and (B) a propylene resin. Here, it is important that (A) has a metallocene-based catalyst as a catalyst and that the α-olefin has 6 to 12 carbon atoms, and the use of such (A) gives an excellent touch (flexibility), The present inventors have found that environmental degradation resistance, abrasion resistance, durability, and mechanical strength are developed, and completed the present invention. Hereinafter, each component of the present invention will be described in detail. In the present invention, (A) the ethylene / α-olefin copolymer rubber is an ethylene / α-olefin copolymer comprising an α-olefin having 6 to 12 carbon atoms. As the α-olefin having 6 to 12 carbon atoms, for example,
Hexene-1, 4-methylpentene-1, heptene-
1, octene-1, nonene-1, decene-1, undecene-1, dodecene-1 and the like. Among them, hexene-1, 4-methylpentene-1 and octene-1 are preferred, and octene-1 is particularly preferred. Octene-1
Is excellent in softening effect even in a small amount, and the obtained copolymer is excellent in mechanical strength. (A) used in the present invention is produced using a known metallocene catalyst. In general, a metallocene-based catalyst is composed of a cyclopentadienyl derivative of a Group IV metal such as titanium or zirconium and a co-catalyst, and is not only highly active as a polymerization catalyst but also obtains a heavy weight as compared with a Ziegler-based catalyst. The molecular weight distribution of the coalesce is narrow, and the distribution of the comonomer α-olefin having 3 to 20 carbon atoms in the copolymer is uniform. (A) used in the present invention is α-
The copolymerization ratio of the olefin is preferably 1 to 60% by weight, more preferably 10 to 50% by weight, and most preferably 20 to 45% by weight. If the copolymerization ratio of the α-olefin exceeds 60% by weight, the hardness and tensile strength of the composition tend to decrease, while if it is less than 1% by weight, the mechanical strength decreases. The density of (A) is 0.8 to 0.9 g / cm.
It is preferably in the range of ³ . The ethylene / α-olefin copolymer used in the present invention preferably has a long-chain branch. The presence of the long-chain branch enables the density to be lower than the ratio (% by weight) of the copolymerized α-olefin without lowering the mechanical strength. Hardness and high strength elastomer can be obtained. Ethylene α with long chain branch
-As an olefin copolymer, USP 5,278,272
And so on. Further, (A) desirably has a DSC melting point peak at room temperature or higher. When it has a melting point peak, the form is stable in the temperature range below the melting point, the handleability is excellent, and the stickiness is small. The melt index of (A) used in the present invention is from 0.01 to 10
Those having a range of 0 g / 10 minutes (190 ° C., 2.16 kg load) are preferably used, and more preferably 0.2 to 10 minutes.
g / 10 minutes. If it exceeds 100 g / 10 minutes, the crosslinking property of the thermoplastic elastomer composition will be insufficient, and if it is less than 0.01 g / 10 minutes, the fluidity will be poor and the processability will be undesirably reduced. (A) used in the present invention may be a mixture of a plurality of types. In such a case, it is possible to further improve the workability. In the present invention, the (B) propylene-based resin is a homoisotactic polypropylene, an isotactic propylene-based resin (block) composed of propylene and another α-olefin such as ethylene, butene-1, pentene-1, and hexene-1. , And random). At least one resin selected from these resins is used in a composition ratio of 1 to 99 parts by weight. Preferably it is 5-90 parts by weight, more preferably 20-80 parts by weight. If the amount is less than 1 part by weight, the fluidity and processability of the composition are reduced, and if it exceeds 99 parts by weight, the flexibility of the composition is insufficient, which is not desirable. In the present invention, (B)
The melt index of the propylene resin is 0.1 to 1
Those having a range of 00 g / 10 minutes (230 ° C., 2.16 kg load) are preferably used. If it exceeds 100 g / 10 minutes, the mechanical strength such as heat resistance and adhesive strength of the composition tends to decrease, and if it is less than 0.1 g / 10 minutes, the fluidity is poor and the moldability deteriorates, which is desirable. Absent. In the present invention, a softening agent (C) can be added to the composition comprising (A) and (B) as required to improve workability. The above (C) is preferably a paraffinic or naphthenic process oil. These are (A) and (B) for adjusting the hardness and flexibility of the composition.
5-250 parts by weight per 100 parts by weight of the composition comprising
Preferably, 10 to 150 parts by weight is used. If the amount is less than 5 parts by weight, flexibility and workability are insufficient, and if it exceeds 250 parts by weight, oil bleeding becomes remarkable, which is not desirable. In the present invention, the composition comprising (A) and (B) is prepared by adding (C) a softening agent to (A) a specific olefin-based elastomer and (B) a propylene-based resin described above. By combining them in a composition ratio, the balance between mechanical strength, flexibility and processability is improved, and they can be preferably used. The composition comprising (A) and (B) provided in the present invention requires that the composition be partially cross-linked with a radical initiator such as an organic peroxide or a radical initiator and a crosslinking assistant. It is. Thereby, it becomes possible to further improve the wear resistance, mechanical strength, heat resistance, and the like. Here, specific examples of the radical initiator preferably used include 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane,
1,1-bis (t-hexylperoxy) -3,3,5
-Trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-
Butylperoxy) cyclododecane, 1,1-bis (t
-Butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl-4,
Peroxy ketals such as 4-bis (t-butylperoxy) butane and n-butyl-4,4-bis (t-butylperoxy) valerate; di-t-butyl peroxide, dicumyl peroxide, t -Butylcumyl peroxide, α, α′-bis (t-butylperoxy-m
-Isopropyl) benzene, α, α'-bis (t-butylperoxy) diisopropylbenzene, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane and 2,5-dimethyl-2,5 Dialkyl peroxides such as -bis (t-butylperoxy) hexyne-3; acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexa Diacyl peroxides such as noyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide and m-trioyl peroxide; t-butylperoxyacetate, t
-Butylperoxyisobutyrate, t-butylperoxy-2-ethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate,
Di-t-butylperoxyisophthalate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxymaleic acid, t-butylperoxyisopropyl carbonate, and cumylperoxyoctate Peroxyesters; and
Hydrogens such as t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide and 1,1,3,3-tetramethylbutyl peroxide Peroxides can be mentioned. Among these compounds, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, di-t-butyl peroxide, dicumyl peroxide, 2,5-dimethyl -2,5-bis (t-butylperoxy) hexane and 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3 are preferred. These radical initiators are used in an amount of 0.02 to 3 based on 100 parts by weight of the composition comprising (A) and (B).
It is used in an amount of part by weight, preferably 0.05 to 1 part by weight. If the amount is less than 0.02 parts by weight, the crosslinking is insufficient, and if it exceeds 3 parts by weight, the physical properties of the composition are not improved, which is not preferable. Further, as a crosslinking aid, divinylbenzene, triallyl isocyanurate, triallyl cyanurate, diacetone diacrylamide, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diisopropenylbenzene, P- quinone dioxime, P, P ^'- dibenzoyl quinone dioxime, phenylmaleimide, allyl methacrylate, N, ^N'-m-
Phenylene bismaleimide, diallyl phthalate, tetraallyloxyethane, 1,2-polybutadiene and the like are preferably used. These crosslinking aids may be used in combination of two or more. These crosslinking aids are used in an amount of 0.1 to 5 parts by weight, preferably 0.5 to 2 parts by weight, per 100 parts by weight of the composition comprising (A) and (B). If the amount is less than 0.1 part by weight, crosslinking is insufficient, and if it exceeds 5 parts by weight, the physical properties of the composition are not improved, and an excessive amount of a crosslinking aid remains, which is not preferable. Further, to the composition comprising (A) and (B) of the present invention, other resins and elastomers may be added to such an extent that their characteristics are not impaired. The polymer composition comprising (A) and (B) in the present invention can be produced through the following processing steps as a specific example. That is, the olefin-based elastomer and the propylene-based resin are mixed well and then charged into a hopper of an extruder. The radical initiator and the crosslinking assistant may be added together with the olefin-based elastomer and the propylene-based polymer from the beginning, or may be added in the middle of the extruder. The oil may be added from the middle of the extruder, or may be added separately at the beginning and during the middle. The olefin-based elastomer and the propylene-based resin may be partially added in the middle of the extruder. When heated and melted and kneaded in an extruder, the elastomer and the radical initiator and the crosslinking auxiliary undergo a crosslinking reaction, and the crosslinking reaction and kneading dispersion are sufficiently performed by further adding and melting oil and kneading. Then remove from the extruder. By pelletizing, pellets of the composition comprising (A) and (B) can be obtained. Further, the composition comprising (A) and (B) of the present invention can contain an inorganic filler and a plasticizer to such an extent that their characteristics are not impaired. As the inorganic filler used here, for example, calcium carbonate, magnesium carbonate, silica, carbon black, glass fiber,
Examples include titanium oxide, clay, mica, talc, magnesium hydroxide, and aluminum hydroxide. Examples of the plasticizer include phthalic acid esters such as polyethylene glycol and dioctyl phthalate (DOP). In addition, other additives, for example, flame retardants, organic and inorganic pigments, heat stabilizers, antioxidants, ultraviolet absorbers,
Light stabilizers, silicone oils, antiblocking agents, foaming agents, antistatic agents, antibacterial agents and the like are also suitably used. A known method can be used for the method for producing an automotive exterior material of the present invention. In particular, an injection molding method and an extrusion molding method are desirable, and there are a method of producing an automobile exterior material from a T-die of a melt extruder, and a method of producing an automobile exterior material of an arbitrary shape by an injection molding machine. In molding, it is also possible to produce a non-slip material by combining a plurality of materials such as two-color molding and insert molding. Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In these examples and comparative examples, the test methods used for evaluating various physical properties are as follows. (1) Environmental Degradation Resistance The molded article was heated in a gear oven at 120 ° C. for 100 hours, the change in color tone was observed, and the environmental degradation resistance was evaluated. (2) Tensile breaking strength [kgf / cm ² ] A molded article is compression-molded to produce a sheet, which is JIS K62
The evaluation was performed at 23 ° C. in accordance with No. 51. (3) Tensile rupture elongation [%] A molded article is compression molded to produce a sheet, which is JIS K62
The evaluation was performed at 23 ° C. in accordance with No. 51. (4) Compression set (C-Set) [%] A molded article is compression-molded to produce a sheet, which is specified in JIS K63.
According to No. 01, evaluation was made at 70 ° C. × 22 hours as an index of durability. The smaller the value, the better the durability. (5) A compression-molded abrasion-resistant molded product is formed into a sheet, and a 5 cm × 5 cm × 2 mm stainless plate with a felt cloth adhered to the lower surface is placed on the sheet, and a load of 100 g / cm ² is applied. , And reciprocated 10,000 times at a speed of 30 reciprocations / minute to observe the surface condition. The following components were used as components used in Examples and Comparative Examples. (A) Ethylene / α-olefin copolymer Copolymer of ethylene and octene-1 (TPE-1) Produced by a method using a metallocene catalyst described in JP-A-3-1630088. The ethylene / octene-1 composition ratio of the copolymer is 72/28 (weight ratio).
(Referred to as TPE-1) Copolymer of ethylene and octene-1 (TPE-2) Produced by a method using a usual Ziegler catalyst. The ethylene / octene-1 composition ratio of the copolymer is 72/2.
8 (weight ratio). (Referred to as TPE-2) Ethylene / propylene / dicyclopentadiene copolymer (TPE-3) Produced by a method using a metallocene catalyst described in JP-A-3-1630088. The composition ratio of ethylene / propylene / dicyclopentadiene in the copolymer is 72/2.
4/4 (weight ratio). (Referred to as TPE-3) (ii) Propylene resin Nippon Polychem Co., Ltd., isotactic polypropylene (referred to as PP) (c) Paraffin oil Idemitsu Kosan Co., Ltd., Diana Process Oil PW-3
80 (referred to as MO) (d) Radical initiator 2,5-dimethyl-2,5-bis (t-manufactured by NOF Corporation)
Butylperoxy) hexane (trade name Perhexa 25)
B) (referred to as POX) (e) Crosslinking aid divinylbenzene (referred to as DVB) manufactured by Wako Pure Chemical Industries, Ltd. Example 1 TPE-1 / PP / POX / DVB / MO
= 75/25 / 0.5 / 1/45 (weight ratio), a twin screw twin screw extrusion having an injection port at the center of the barrel and a kneading section before and after the injection port. Machine (40
mmφ, L / D = 47) by a dynamic crosslinking method. That is, after mixing other than MO in the above composition ratio, the mixture is introduced into a twin-screw extruder (cylinder temperature 220 ° C.), and then a predetermined amount of MO is injected by a pump from an injection port at the center of the extruder. Melt extrusion was performed and pelletized with a pelletizer. The pellets thus obtained were formed into an automobile louver protector having a size of 20 cm in width and 1 m in length using an injection molding machine (extrusion temperature: 220 ° C.). ), No change in color tone from the initial white color even at 120 ° C. for 100 hours in a gear oven, and has excellent environmental degradation resistance. The 2 mm sheet obtained by compression molding the louver protector has excellent wear resistance, durability and mechanical strength. Tensile rupture strength: 82 [kgf / cm ² ] Tensile rupture elongation: 370 [%] Compression set (C-Set): 39 [%] Abrasion resistance: scars scarcely noticeable [Comparative Example 1] In Example 1, TPE-1 was replaced with TPE-2.
The same experiment was repeated except for changing to. The obtained louver protector was placed in a gear oven at 120 ° C.,
Although there is no change in color tone with respect to the initial white color even at 00 hours, and excellent in environmental degradation resistance, the 2 mm sheet obtained by compression molding a louver protector has abrasion resistance, durability and mechanical strength. Is inferior. Tensile breaking strength: 59 [kgf / cm ² ] Tensile breaking elongation: 270 [%] Compression set (C-Set): 53 [%] Abrasion resistance: scratches are noticeable [Comparative Example 2] In Example 1, TPE-1 was replaced with TPE-3.
The same experiment was repeated except for changing to. The obtained louver protector was placed in a gear oven at 120 ° C.,
At 00 hours, the initial white color changed to yellow. Also,
A 2 mm sheet obtained by compression molding a louver protector is inferior in abrasion resistance, durability and mechanical strength. Tensile rupture strength: 49 [kgf / cm ² ] Tensile rupture elongation: 200 [%] Compression set (C-Set): 68 [%] Abrasion resistance: scratches are noticeable. The automotive exterior material of the present invention has excellent environmental degradation resistance, abrasion resistance, durability and mechanical strength,
Because of its excellent tactile sensation (flexibility), it can be widely used in various automotive exterior fields such as bumpers and louver protectors, and plays a large role in the industrial world.

Claims (1)

Claims: (A) Ethylene and α-C 6 -C 12
1 to 99 parts by weight of an ethylene / α-olefin copolymer produced using a metallocene-based catalyst composed of an olefin and (B) 1 to 99 parts by weight of a propylene-based resin [The total amount of (A) and (B) is 100 parts by weight. Automotive exterior material comprising a partially or completely crosslinked composition comprising: