JPH08231789A - Thermoplastic elastomer composition - Google Patents

Abstract

PURPOSE: To obtain a thermoplastic elastomer composition comprising an olefinic copolymer rubber, a paraffinic oil and crystalline butene-1 resin in specific amounts, respectively, excellent in a non-smelling property, an economical view and the balance of physical properties such as flexibility, strength and compression permanent deformation, and useful for automotive inner parts, automotive outer parts, etc. CONSTITUTION: This composition comprises (A) 40-99 pts.wt. of an olefinic copolymer rubber, (B) 1-60 pts.wt. of a paraffinic oil (e.g. the polymer having a weight-average mol.wt. of 300-2000; a kinematic viscosity of 20-800 centistokes at 40 deg.C, a fluid point of 0 to -40 deg.C, and an ignition point of 200-400 deg.C), and (C) crystalline butene-1 resin (e.g. a density of 0.890-0.925g/cm<3> , a melt flow rate of 0.01-1000g/10min (at 190 deg.C under a weight of 2.16kg), a crystallization degree of >=30%, and a weight-average mol.wt. of 10,000-3,000,000) in an amount of 10-900 pts.wt. per 100 pts.wt. of the total amount of the components A and B, and has a JIS-K7203 flexural elastic modulus of <2000kg/cm<2> .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-crosslinked thermoplastic elastomer composition having excellent rubber elasticity and excellent scratch resistance.

[0002]

2. Description of the Related Art Olefinic thermoplastic elastomers (hereinafter sometimes simply referred to as "olefinic TPEs") not only exhibit rubber elasticity similar to that of vulcanized rubbers, but also thermoplastics such as polyethylene and polypropylene. Shows good moldability equivalent to that of resin. Utilizing this fact, it can be used for molding in the same manner as ordinary thermoplastic resins. The molded product is mainly used for rubber elasticity, bumper,
It is used as exterior parts for automobiles such as exterior moldings, mudguards, and emblems, interior parts for automobiles such as door trims and pillars, and skin material sheets for interior parts of automobiles, and for general industrial parts.

[0003]

[Problems to be Solved by the Invention]
Although the hardness of the PE composition is adjusted by increasing the amount of polypropylene added, it is common that the PE composition becomes harder and rubber elasticity deteriorates. Therefore, when rubber elasticity is required, the crosslinking treatment is indispensable also from the viewpoint of physical property balance such as flexibility, mechanical strength and compression set. However, there are problems in product cost such as an increase in the number of steps due to crosslinking, and technical problems in that an odor due to the crosslinking agent and the crosslinking aid remains.

[0004]

[Means for solving the problem]

[Summary of the Invention] The present inventors have conducted intensive studies in view of the above problems, and as a result, by blending a specific amount of a crystalline butene-1 resin with an olefinic TPE, a rubber can be obtained without crosslinking treatment. The present inventors have completed the present invention by discovering that they have excellent elasticity and also have improved scratch resistance as compared with a cross-linked olefin-based TPE. That is,
The thermoplastic elastomer composition of the present invention comprises the following component A, component B and component C, and JIS-K7203
The bending elastic modulus is less than 2,000 kg / cm ² . Component A: Olefin-based copolymer rubber 40 to 99 parts by weight Component B: Balafin-based oil 60 to 1 part by weight Component C: Crystalline butene-1 resin 10 per 100 parts by weight of the total amount of the above components A and B
~ 900 parts by weight.

[Detailed Description of the Invention] [1] Thermoplastic Elastomer Composition (1) Constituent Components (a) Component A: Olefin Copolymer Rubber The olefin copolymer rubber used in the present invention is ethylene. , Propylene copolymer rubber (EPM), ethylene / butene-1 copolymer rubber (EBM), and non-conjugated dienes such as 1,4-hexadiene and other aliphatic dienes, 5-
Ethylidene norbornene, 5-methyl norbornene, 5
-Ethylene / propylene / non-conjugated diene copolymer rubber (EPDM) using vinyl norbornene, dicyclopentadiene, dicyclooctadiene and the like can be mentioned. Among these, EBM and EPD from the viewpoint of scratch resistance
M is preferred.

The Mooney viscosity (ML _{1 + 4} (100 ° C.)) of the olefin copolymer rubber at 100 ° C. is 10 to ₄
00. When the Mooney viscosity exceeds the above range, the molding appearance is poor, and when it is less than the above range, the rubber elasticity is poor. The Mooney viscosity in the above range is preferably 15 to 350.

(B) Component B: Balafin-based oil The paraffin-based oil which is a constituent of the thermoplastic elastomer composition for injection molding of the present invention has a weight average molecular weight of 300 to 2,000, preferably 500 to 1, Fifty
Kinematic viscosity of 0 to 40 ° C is 20 to 800 centistokes (c
st), preferably 50-600 cst, with a fluidity of 0
-40 ° C, preferably 0 to -30 ° C, and flash point (C
OC) is 200 to 400 ° C., preferably 250 to 350
Paraffinic oil at ℃ is preferably used.

The paraffinic oil is generally a mixture of three aromatic rings, naphthene rings and paraffin rings, and the number of carbon atoms in the paraffin chain is 50 in the total carbon.
% Oils are called paraffinic oils, naphthenic ring carbon atoms of 30 to 45% are called naphthenic oils, and aromatic carbon atoms of more than 30% are called aromatic oils. Are classified. Among these various oils, when an oil other than paraffinic oil is used in the present invention, the weather resistance is particularly poor and the remarkable effect of the present invention cannot be obtained. Therefore, the paraffin chain carbon number is 50% or more of the total carbon. It is necessary to use the paraffinic oil of Further, the paraffin oil may be added as an oil-extended rubber to the olefin copolymer rubber of the component A in advance.

(C) Component C: Crystalline Butene-1 Resin The crystalline butene-1 resin which is a constituent of the thermoplastic elastomer composition for injection molding of the present invention includes butene-1.
A crystalline resin such as a homopolymer or a polymer synthesized from a small amount (20% by weight or less) of another comonomer such as ethylene or propylene and a monomer containing butene-1 as a main component and having a density of 0.890 to 0. 925 g / cm ³ , preferably 0.893 to 0.923 g / cm ³ , particularly preferably 0.900 to 0.920 g / cm ³ ; melt flow rate (MFR: JIS K7210 compliant, 190 ° C., 2.
16 kg load) is 0.01 to 1,000 g / 10 min, preferably 0.05 to 500 g / 10 min, preferably 0.1.
1 to 100 g / 10 minutes; crystallinity of 30% or more, preferably 30 to 70%; weight average molecular weight of 10,000 to
3,000,000, preferably 50,000-2,5
Those of 0,000 are preferably used.

The "weight average molecular weight" is a polystyrene equivalent weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions. (Conditions) Equipment; 150C ALC / GPC (MILLI
Column: AD80M / S (manufactured by Showa Denko KK) Three: Solvent: o-dichlorobenzene Temperature: 140 ° C. Flow rate: 1 ml / min Injection amount: 200 μl Concentration: 2 mg / ml (antioxidants 2, 6 -0.2% by weight of di-t-butyl-p-phenol was added. The concentration was detected by an infrared spectrophotometer MIRAN 1A manufactured by FOXBORO at a wavelength of 3.42 μm.)

(D) Component D: Olefin-based resin (optional component) In the thermoplastic elastomer composition for injection molding of the present invention, the above-mentioned component C used as any suitable compounding component.
The olefin resin other than is an olefin homopolymer or copolymer, for example, isotactic polypropylene or propylene and other small amount of α-olefin, for example, ethylene, 1-butene, 1- Examples thereof include copolymers with hexene, 4-methyl-1-pentene and the like.

Further, polyethylene resins such as low density polyethylene (branched ethylene polymer), medium density and high density polyethylene (linear ethylene copolymer), ethylene / vinyl acetate copolymer, ethylene / (meth) Examples thereof include ethylene / α-olefin copolymers such as acrylic acid copolymers and ethylene / (meth) acrylic acid ester copolymers.

Of these, particularly preferable from the viewpoint of improving heat resistance, isotactic polypropylene or propylene and a small amount of other α-olefins such as ethylene, 1-butene, 1-hexene and 4-methyl-1-. It is a copolymer with pentene and the like. MFR (JIS K721
0 conformity; 230 ° C, 2.16kg load) is generally 0.0
1 to 300 g / 10 minutes, preferably 0.05 to 200 g
/ 10 minutes, particularly preferably 0.1 to 100 g / 10 minutes, and it is preferable to use an olefin resin having a crystallinity of 20 to 70%.

(E) Other components (optional components) The above olefinic TPE component may be blended with any other blending component according to various purposes within a range that does not significantly impair the effects of the present invention. Specifically, an antioxidant,
Various additives such as heat stabilizer, light stabilizer, ultraviolet absorber, neutralizing agent, lubricant, antifogging agent, antiblocking agent, slip agent, colorant, flame retardant, dispersant and antistatic agent may be added. it can.

Particularly, amide compounds such as olefinic acid amide and stearic acid amide are preferable as the lubricant, and silicone such as dimethyl silicone oil and phenylmethyl silicone oil is preferably added as the anti-blocking agent and slip agent. Further, by blending various thermoplastic resins, various elastomers, various fillers such as talc, and various fillers such as calcium carbonate within a range that does not significantly impair the effects of the present invention, fluidity (moldability), impact resistance It is possible to improve dimensional properties and the like.

As the thermoplastic resin in the above-mentioned additional compounding material component, other than the above-mentioned component C or component D, for example, ethylene-
Polyolefin resin such as vinyl acetate copolymer, ethylene, acrylic ester copolymer; styrene resin such as polystyrene, acrylonitrile / styrene copolymer, acrylonitrile / butadiene / styrene copolymer; polyphenylene ether resin: nylon 6, Nylon 66
Polyamide resin such as polyethylene terephthalate,
Polyester resins such as polybutyl terephthalate; polyoxymethylene resins such as polyoxymethylene homopolymers and polyoxymethylene copolymers; and polymethylmethacrylate resins can be used. The thermoplastic resin used may be one kind or plural kinds.

Styrene-based TPE can be used as the various elastomers in the additional compounding material component. Styrene-based TPE is a hydrogenated product of a styrene / conjugated diene block copolymer, and specifically, a styrene / ethylene / butylene / styrene copolymer (SEB
S) or styrene / ethylene / propylene / styrene copolymer (SEPS). The elastomer to be used may be one kind or plural kinds.

(2) Mixing ratio As for the mixing ratio of each component constituting the thermoplastic elastomer composition of the present invention, the total amount of the component A and the component B is 100.
It is used in an amount of 40 to 99 parts by weight, preferably 40 to 95 parts by weight, and more preferably 40 to 90 parts by weight.
Therefore, the blending ratio of the component B is 60 to 1 parts by weight, preferably 60 to 5 parts by weight, more preferably 60 to 10 parts by weight.

When the blending ratio of the component A is less than the above range (therefore component B exceeds the above range), the rubber elasticity and heat resistance of the thermoplastic elastomer composition for injection molding obtained are poor,
The bleeding of the softening agent deteriorates. On the other hand, if it exceeds the above range (therefore component B is less than the above range), the moldability is deteriorated.

The mixing ratio of the component C is 10 to 900 parts by weight based on 100 parts by weight of the total amount of the components A and B,
Preferably 15 to 600 parts by weight, more preferably 20
~ 300 parts by weight. When the compounding ratio of the component C is less than the above range, the scratch resistance is poor, and when it exceeds the above range, the cost becomes high, and the flexibility, especially the elongation of the elastomer composition is lowered.

The component D may be blended in an arbitrary manner, but the blending ratio in the case of blending the component D is 1 total amount of the component A and the component B.
1 to 100 parts by weight, preferably 1 to 100 parts by weight
To 90 parts by weight, more preferably 1 to 80 parts by weight.
When the compounding ratio of the component D exceeds the above range, the rubber elasticity is lowered.

(3) Production of TPE composition The thermoplastic elastomer composition (TPE composition) of the present invention
In the production of, the above-mentioned components can be produced by a usual method of mechanically melt-kneading. Examples of the melt kneader used in the mechanical melt kneading include:
A single screw extruder, a twin screw extruder, a Brabender plastograph, a Banbury mixer, a kneader blender, a roll etc. can be mentioned.

The thermoplastic elastomer composition obtained is
Flexural modulus according to JIS-K7203 is 2,000kg
/ Cm < ² >, preferably less than 1,500 kg / cm < ² >, particularly preferably 1,300 to 0 kg / cm < ² >. If the flexural modulus exceeds the above range, flexibility and rubber elasticity tend to be inferior, which is not suitable. Further, those below the above range are inferior in scratch resistance.

[II] Molding The thermoplastic elastomer composition for injection molding of the present invention has an injection molding method (insert molding method, two-color molding method, sandwich molding method, gas injection method) used in ordinary molding methods for thermoplastic resins. Molding method etc.), extrusion molding method (single-layer extrusion method, multi-layer extrusion method, etc.), blow molding method, T-die molding method and calender molding method can be applied to various molding methods to mold the molded article.

[0025]

【Example】

The present invention will be described more specifically by the following examples. [1] Evaluation Method In the examples described below, the physical properties of the thermoplastic elastomer, scratch resistance, bleeding property of paraffin oil, etc. were evaluated by the methods described below.

(1) Bending elastic modulus Using an in-line screw type injection molding machine {Toshiba Machinery Co., Ltd. small injection molding machine; IS90B}, a cylinder temperature of 210 ° C., a mold temperature of 40 ° C., an injection pressure of 500.
kg / cm ² becomes the condition, 120mm × 80mm × 2m
An m-sized sheet was formed. Using this sheet, J
A test piece according to IS-K7203 was prepared by a punching method. Regarding the obtained test piece, JIS-K720
The flexural modulus [unit: kg / cm ² ] was measured according to 3.

(2) 300% stress From the sheet molded by the method described in (1) above, JIS
A test piece according to -K6301 was prepared by punching in the lateral direction by a punching method. Regarding the obtained test piece, JIS-
300% stress based on K6301 [Unit: kg / cm
² ] was measured. 300% stress is a measure of scratch resistance, and if the flexural modulus is the same, the larger the 300% stress, the better the scratch resistance, and the smaller the 300% stress, the worse the scratch resistance.

(3) Compression set From the sheet molded by the method described in (1) above, JIS
A test piece according to K6301 was prepared by a punching method. The compression set [unit:%] of the obtained test piece was measured according to JIS-K6301 under the conditions of 70 ° C. and 22 hours. If the bending elastic modulus is the same, the smaller the compression set, the better the rubber elasticity.

(4) Scratch resistance The sheet molded by the method described in (1) above was left for 2 days at 23 ° C., and the surface was scratched with a claw to confirm scratch resistance. Those that were not easily scratched were rated as good, and those that were easily scratched were rated as bad.

(5) Bleedability of paraffinic oil The sheet molded by the method described in (1) above is used at room temperature for 3 days.
The sample was stored for 0 days, and the case where the paraffinic oil clearly bleeds on the surface of the sheet was designated as ×, and the case where it was not. [II] Raw Materials Components A, B, C and D used in Examples and Comparative Examples are shown in Tables 1 to 4 below.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

[0034]

[Table 4]

[III] Experimental Examples Examples 1 to 12, Comparative Examples 1 to 3, Comparative Examples 5 to 6 The raw materials shown in the above raw materials were blended in the proportions shown in Tables 5 and 6, and the blended 100 parts by weight of a phenolic antioxidant "Irganox 1010" 0.
After adding 1 part by weight and kneading at a temperature of 170 ° C. for 6 minutes with a Banbury mixer, L / D = 33, cylinder diameter 4
Using a 5 mm twin-screw extruder, pellets of the thermoplastic elastomer composition of the present invention were obtained. Using the pellets of this thermoplastic elastomer composition, a sheet having a thickness of 2 mm was molded by performing the injection molding shown in the above evaluation method. Various evaluations are performed on the obtained sheet, and the results are
The results are shown in Table 6 and Table 6.

Comparative Example 4 The raw materials shown in the above raw materials were blended in the proportions shown in Table 6, and 0.1 part by weight of the phenolic antioxidant "Irganox 1010" was added to 100 parts by weight of the blended material. Was added, and the mixture was kneaded with a Banbury mixer at a temperature of 170 ° C. for 6 minutes and then cut into sheets to obtain pellets. Then, using a twin-screw extruder having L / D = 33 and a cylinder diameter of 45 mm, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane-3 was added as peroxide to 100 parts by weight of the pellets. 0.25 parts by weight and 0.4 parts by weight of divinylbenzene as a crosslinking aid were added, and heat treatment (crosslinking treatment) was performed at a set temperature of 220 ° C. to obtain pellets of the partially crosslinked thermoplastic elastomer composition.

Using the pellets of the partially crosslinked thermoplastic elastomer composition, a sheet having a thickness of 2 mm was formed by performing the injection molding shown in the above evaluation method. Various evaluations were performed on the obtained sheet, and the results are shown in Table 6. The obtained sheet had a peculiar malodor due to the crosslinking agent and the crosslinking aid.

[0038]

[Table 5]

[0039]

[Table 6]

Claims (2)

[Claims] 1. A component A, a component B, and a component C described below, which have a flexural modulus of 2,000 according to JIS-K7203.
A thermoplastic elastomer composition which is less than 0 kg / cm ² . Component A: Olefin-based copolymer rubber 40 to 99 parts by weight Component B: Paraffinic oil 60 to 1 part by weight Component C: Crystalline butene-1 resin 10 per 100 parts by weight of the total amount of the above components A and B
~ 900 parts by weight. 2. The thermoplastic elastomer composition according to claim 1, which further contains the following component D. Component D; olefin resin other than component C 1 to 10 per 100 parts by weight of the total amount of component A and component B
0 parts by weight.