JPS60158224A - Granulation of elastomeric composition - Google Patents

Abstract

PURPOSE:To obtain granules of the titled composition excellent in flexibility, heat distortion resistance and mechanical strength, by mixing a hydrogenated block copolymer with a nonaromatic rubber softener, a polypropylene copolymer and a polysiloxane, and granulating the mixture. CONSTITUTION:0.05-20pts.wt. polysiloxane is added to 100pts.wt. elastomer composition of a JIS-A hardness of 40-75, comprising 100pts.wt. hydrogenated block copolymer of the formula (wherein A is a monovinyl-substituted aromatic hydrocarbon polymer block, B is a conjugated diene elastomeric polymer block, and n is 1-5), 150-300pts.wt. nonaromatic rubber softener, 30-400pts.wt. propylene copolymer which is a copolymer of propylene with a 1-olefin other than propylene and has a density of 0.883-0.901g/cm<3> and 0-900pts.wt. inorganic filler, and the resulting mixture is granulated.

Description

Detailed Description of the Invention [1] Background of the Invention The present invention is directed to the production of a novel thermoplastic elastomer composition that is relatively inexpensive, highly flexible, and has excellent heat deformation resistance and mechanical strength. It concerns the grain method.

In recent years, rubber-like materials that do not require a vulcanization process,
Thermoplastic elastomers (hereinafter abbreviated as TPE), which have moldability similar to that of thermoplastic resins, are attracting attention in the fields of automobile parts, home appliance parts, electric wire coatings, footwear, miscellaneous goods, and the like.

Currently, various types of TPE such as polyolefin-based, polyurethane-based, polyester-based, polystyrene-based, and polyvinyl chloride-based polymers have been developed and are commercially available.

Among these, polystyrene TPEs such as styrene-butadiene block polymer (SBS) and styrene-isoprene block polymer (SIS) are highly flexible and have good rubber elasticity at room temperature. The resulting TPE compositions have excellent processability, but because these polymers have double bonds as conjugated diene blocks in their molecules, they have problems with heat aging resistance (thermal stability) and weather resistance. Therefore, by hydrogenating this intramolecular double bond, a more stable nidistomer is obtained, and a composition is introduced in which this hydrogenated block copolymer is blended with a hydrocarbon oil and an α-olefin polymer. It's the first time it's been done.

However, these TPE compositions still do not have a sufficient quality balance of flexibility, mechanical strength, and heat deformation resistance, and in particular, the amount of hydrocarbon oil blended as a softening agent is generally 100 parts by weight of the hydrogenated derivative. On the other hand, if the amount is less than 150 parts by weight, and if the amount is more than 150 parts by weight, the flexibility of the composition will be increased but the mechanical strength will be greatly reduced, so the economic efficiency of adding a large amount of softener cannot be expected. Therefore, the present inventors have previously improved this point and provided a composition that can incorporate a large amount of softener and has a good quality balance of flexibility, mechanical strength, and heat deformation resistance (Japanese Patent Application Laid-Open No. 58-206
644).

However, subsequent studies revealed that the highly flexible J
Compositions with IS-A hardness of 40 to 75 provide stable granulation7) (
It turns out that it has some drawbacks.

In other words, this composition has low hardness, high flexibility, and excellent rubber elasticity, so when the strand is bitten into the rotating blade and fixed blade of the strand cutter during granulation, the tip of the strand flies off, resulting in poor cutting or poor cutting. Stable granulation production is difficult because it gets caught in the rotating blade.

Eliminating this drawback is a practically essential task.

[[l] Summary of the Invention The present invention provides a hydrogenated derivative of a block copolymer of styrene and a conjugated diene by blending a specific propylene copolymer with a large amount of a softening agent, resulting in high flexibility. At the same time, the present invention provides a relatively inexpensive method for granulating an elastomeric composition that has excellent heat deformation resistance and mechanical strength.

That is, the present invention has the following formula: (a) General formula A+B A)n where A is a monovinyl-substituted aromatic hydrocarbon polymer block, B is a conjugated diene elastomeric polymer block, and n is 1 to 5. is an integer. ) 100 parts by weight of a hydrogenated derivative of a block copolymer represented by (b) 150 to 300 parts by weight of a softener for non-aromatic rubber, (C) one or two of propylene and 1-olefins other than propylene. A copolymer with more than one species, with a density of o, g
100 parts by weight of an elastomeric composition having a JIS-A hardness of 40 to 75, consisting of 30 to 400 parts by weight of a propylene copolymer of 83 to 0.90 tt/al and 0 to 900 parts by weight of (d) an inorganic filler. , polysiloxane 0°05~20
This is a method for granulating an elastomeric composition, characterized in that the composition is granulated by containing part by weight of the elastomeric composition.

The granulation method of the present invention enables economical granulation of TPE4 product Q with excellent flexibility, which could not be granulated conventionally, resulting in significant streamlining of all processes including packaging, transportation, and molding. This has made it possible to take simpler and more economical measures.

[1111 Detailed Description of the Invention Component (a) The component (a) used in the present invention has a general formula of A+B-A.
) A hydrogenated derivative obtained by hydrogenating a block copolymer represented by n, in the above general formula,
A is a monovinyl-substituted aromatic hydrocarbon polymer block,
B is an elastomeric polymer block of conjugated diene, and n is an integer from 1 to 5.

The monovinyl-substituted aromatic hydrocarbon monomer constituting the polymer block A is preferably styrene, and α-methylstyrene or the like may also be used. The conjugated diene monomer in polymer block B is preferably butadiene or isoprene, or may be a mixture of both. When butadiene is used as the single conjugated diene monomer to form polymer block B, the block copolymer retains its elastomeric properties after being hydrogenated to saturate the double bonds. In order to achieve this, it is preferable to adopt polymerization conditions such that the 1,2-microstructure accounts for 20 to 50% of the microstructure in the polybutadiene block, and more preferably, the 1,2-microstructure accounts for 35 to 45%. belongs to.

The weight average molecular weight of polymer block A in the block copolymer is 5,000 to 125,000. Block B is 15000
A value in the range of 250,000 to 250,000 is preferred. The proportion of the polymer block B in the total copolymer is at least 65% by weight.

Many methods have been proposed for producing these block copolymers, but a typical method is, for example, the method described in Japanese Patent Publication No. 40-23798, using a lithium catalyst or a Ziegler type catalyst. It can be obtained by block polymerization in an inert solvent.

The hydrogenation treatment of these block copolymers is carried out in an inert solvent by the method described in the specifications of Japanese Patent Publication No. 42-8704, Japanese Patent Publication No. 43-6636, or Japanese Patent Publication No. 46-20814. Hydrogenated in the presence of a hydrogenation catalyst. In this hydrogenation, at least 50%, preferably 80% or more of the olefinic double bonds in polymer block B are hydrogenated, and 25% or less of the aromatic unsaturated bonds in polymer block A are hydrogenated. be done.

One such hydrogenated block copolymer is commercially available from Shell Chemical Company under the trade name rKRATON-G.

Component (b) The rubber softener used as component (b) in the present invention is:
Non-aromatic mineral oils or liquid or low molecular weight synthetic softeners are suitable. Mineral oil-based rubber softeners, called process oils or extender oils, are generally used to soften, increase the volume, and improve processability of rubber.
A mixture of naphthene rings and paraffin chains, where the number of carbon atoms in the paraffin chains accounts for 50% of all carbons.
Those that account for the above are called paraffinic, those that have 30 to 45% of the naphthenic carbon atoms are naphthenic, and those that have more than 30% of aromatic carbons are aromatic. The mineral oil rubber softener used as component (b) of the present invention is preferably a naphthenic or paraffinic one in the above category, and an aromatic rubber softener having an aromatic carbon number of 30% or more The composition with (a) is unfavorable from the viewpoint of dispersibility. The properties of these non-aromatic rubber softeners include a kinematic viscosity of 20 to 5 QOcst at 37-8°C, a pour point of -10 to -15°C, and a flash point of 170 to 300.
Indicates °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 (component (b)) is 150 to aOO parts by weight, preferably 150 to 250 parts by weight, per 100 parts by weight of component (a). If the amount exceeds 300 parts by weight, the softener tends to bleed out, which may result in tackiness in the final product and also deteriorate mechanical properties. Still, a blending of 150 parts by weight or less may be practical, but is insufficient from an economic point of view.

Description: In the present invention, a specific propylene copolymer is used as component (e). This material acts as a hard segment in the nidistomeric composition of the present invention, adjusts the flexibility (hardness) of the composition, and improves processability, heat deformation resistance, and mechanical strength.

The specific propylene copolymer used in the present invention is a copolymer of propylene and one or more 1-olefins other than propylene, and has a density of 0.883 to
0.901 t7dl.

Examples of 1-olefins other than propylene include ethylene,
Examples include butene-1, pentene-1, hexene-1,4-methylpentene-1, etc., and among these, ethylene and hexene-1 are particularly preferred.

Such propylene copolymers are disclosed in, for example, Japanese Patent Application No. 1983.
-143899, JP-A No. 55-165908, JP-A-55-161815, JP-A-55-748, JP-A-54-106597, etc. to achieve high activation. It can be produced by block or random copolymerization of propylene and 1-olefin in the presence of a stereoregular catalyst consisting of treated titanium trichloride and an organoaluminum compound.

The propylene copolymer used as component (e) in the present invention has a density of 0.883 to 0°gg1.
By selecting the polymerization conditions, copolymerization format (block or random or a combination thereof), the number of 1-olefins contained, etc., it is possible to obtain the desired density. The molecular weight of the copolymer is MFR (AS
TM-D-1238, L condition, 230°C) is 0.1 to 5
0? /10 minutes, preferably 0.5 to 30 f/10 minutes.

If the density of the propylene copolymer used as component (c) exceeds 0.901 f/rl, the flexibility of the resulting composition will be impaired and the tensile strength and elongation will be significantly reduced. Furthermore, when a material with a density lower than o,s s 3 t/* is used, the mechanical strength will be low and the heat deformation resistance will be greatly deteriorated.

The blending amount of the propylene copolymer as component (e) is as follows:
30 to 400 per 100 parts of the hydrogenated derivative of a)
If the amount exceeds 400 parts by weight, the hardness of the resulting composition will be too high, resulting in loss of flexibility and a product with a rubbery feel will not be obtained.

Preferred formulations range from 50 to 300 parts by weight.

Component (d) An inorganic filler may be added to the composition of the present invention as required. This inorganic filler has the advantage of being able to reduce product costs as a filler. Examples of inorganic fillers include calcium carbonate, carbon black, talc, magnesium hydroxide, mica, clay, barium sulfate, natural silicic acid, synthetic silicic acid (white carbon), and titanium oxide. Black, furnace black, etc. can be used. Among these inorganic fillers, calcium carbonate and furnace black are economically advantageous and preferable.

The blending amount of the inorganic filler is 1 of the hydrogenated derivative of component (a).
00 parts by weight of 90 parts by weight, preferably up to 500 parts by weight. If the amount exceeds 900 parts by weight, the mechanical strength of the composition will drop significantly, and the hardness will increase, resulting in a loss of flexibility, making it impossible to obtain a product with a rubbery feel.

Polysiloxane The polysiloxane used in the present invention has the general formula -(Rz
Polyorganosiloxane represented by SiO)1 (R: organic group, n: integer) is suitable, and its viscosity ranges from several centistokes to hundreds of thousands of centimeters). The viscosity is determined by n.

Various types of R groups can be selected, including the typical methyl group, phenyl group, chlorophenyl group, long-chain alkyl group, and trifluoroalkyl group.

Specifically, polydimethylsiloxane, polydimethyl-
diphenylsiloxane, polydimethyl-methylphenylditetraxane, polymethylnohydrodienesiloxane,
These include polydiphenylsiloxane and polymethylphenylsiloxane. The viscosity is 100 to 100,000
Centistoke (room temperature) is preferred.

The blending amount of this substance is 0.05 to 100 parts by weight of the elastomeric composition consisting of the above components (a) to (d).
20 parts by weight, preferably Fi, 0.5 to 10 parts by weight. If it is less than 0.05 parts by weight, the effects described below will be insufficient and dust will form, and if it is more than 20 parts by weight, the effect of mixing into the composition will be insufficient and it will not be possible to make it exist uniformly in the composition.

Composite The elastomeric composition of the present invention comprises the components (a) to
(d) is obtained by compounding, and the blending ratio of each component is selected within the above-mentioned blending range of each component so that the JIS-A hardness is in the range of 40 to 75.

This elastomeric composition is produced by granulating (strand cutting) a composite composition using an extruder or the like, which is a normal mechanical melt-kneading method. The object of the present invention is achieved by blending or surface coating polysiloxane in a predetermined area. The effect of this polysiloxane in enabling granulation was unexpected.

In this composition, since a large amount of the softener component (b) is used, components (a), component (b), and in some cases component (c) are also added, and a common solvent such as toluene, etc. is added in advance. After that, the crumb is removed by steam stripping to form a crumb, and the resulting crumb is composited with other components by a mechanical melting method, or the method disclosed in Japanese Patent Application Laid-Open No. 58-196244, which was invented by the present inventors, is This method can be adopted.

Mechanical melt-kneading methods include single-screw extruders, twin-screw extruders,
Banbury Mixer 1 A general-purpose melt mixer such as various kneaders can be used.

Note that a composition having a high hardness of JIS-A hardness of 75 or higher can be easily granulated without containing polysiloxane.

Applications and Uses The composition of the present invention may contain additives such as pigments, heat stabilizers, antioxidants, ultraviolet absorbers, etc., if necessary, as is done for ordinary resin compositions.

Furthermore, the granulated pellets obtained in the present invention can be molded with a commonly used thermoplastic resin molding machine, and can be molded using thermoplastic resin molding methods such as injection molding, extrusion molding, blow molding, and calendar molding. It is applicable to various electric wire coatings (insulation, sheath), home appliance parts, automobile parts, and other industrial parts. Specific applications include various gaskets, flexible tubes, hoses, X coatings, weather strips, flexible bumpers, side bumpers, moldings, filler panels, lamp housings, wire cable coatings, air intake hoses, etc.

rl'llll Examples In these Examples and Comparative Examples, the test methods used for various evaluations are as follows.

(1) MFR (f/10 minutes) ASTM-D-1238, L conditions, 230°C.

(2) Density (4/+t) JIS-6760, density gradient tube method, 23°C.

The press sheet was cut into pieces of appropriate size and heated at 105°C for 1.
It was annealed for 5 hours, cooled to room temperature, and measured 1 hour later.

(3) Hardness [-] JIS-ni-6301, A type.

(4) Tensile strength [Chest/Ca] JIS-6301, the sample used was a press sheet with a thickness of 2, and the test piece was a No. 3 type.

(5) Tensile strength [%] JIS-6301, the sample used was a 2fi thick press sheet, and the test piece was No. 3 type.

(6) Heating and pressing deformation rate [%] A sample (1crnX1
m x 2 m + m thickness) was attached, a load of 3 kg was applied, the sample was left for 1 hour, the load was removed, the thickness of the sample was measured 10 minutes later, and the rate of change from the initial thickness was calculated.

(7) Press molding conditions for evaluation: 7 minutes at a temperature of 200°C and a pressure of 1oKg/-, then 1
Press for 3 minutes at a pressure of 00Kg/-, 150Kg/cr
Cool in water for 2 minutes at a pressure of 1 liter. However, the pressing temperature for preparing samples for density measurement is 230°C.

Further, each component used in Examples and Comparative Examples is as follows.

(1) Component (a) KRATON-G 1651 (13
rookfield viscosity 220% by weight toluene solution,
2000 eps, 77° F) (2) Component (6) Diana Process Oil P W-90 manufactured by Idemitsu Kosan Co., Ltd. [paraffinic, kinematic viscosity: 95.54 est (40°C)
); 11.25 cst (100°C), average molecular weight: 539, ring analysis: CN = 29.0%: CP = 71.
0%] (3) Component (c) The propylene copolymers shown in the following table were used. All of them are Noblen manufactured by Mitsubishi Yuka Co., Ltd.

(Left below) (4) Component (d) Calcium carbonate with an average particle size of 2.5 microns, surface-treated with higher fatty acid ester.

(5) Component (e) 8H200 manufactured by Toray Silicone (3000 centistokes) Example Each component in the proportions shown in Table 1 was mixed at room temperature for 5 minutes to homogenize using a Henschel mixer, and then mixed using a twin screw extruder. The kneaded composition was extruded at 200° C., 220 r, p6m, and the strands were cooled in a water tank, and then the granulation processability (splatterability, winding ability, etc.) using a strand cutter was evaluated.

When a predetermined amount of polysiloxane was blended, there was no problem with extrusion processability, but when polysiloxane was not blended, the strands flew off and no granulation could be achieved.

(Margin below)

Claims (1)

[Claims] 1. (a) General formula % formula %) (where A is a polymer block of monovinyl-substituted aromatic hydrocarbon, B is an elastomeric polymer block of conjugated diene, and n is 1 100 parts by weight of a hydrogenated derivative of a block copolymer represented by Copolymer with one or more olefins, with density o, s
s 3 to 0.901 t/di, 30 to 400 parts by weight of a propylene copolymer and (d) 0 to 900 parts by weight of an inorganic filler to 100 parts by weight of an elastomeric composition having a JIS-A hardness of 40 to 75. , polysiloxane 0°05~20
A method for granulating an elastomeric composition, which comprises granulating the elastomeric composition in parts by weight.