JP2000336175A - Production of thermoplastic elastomer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve conventional problems readily causing blocking and incapable of carrying out handling by usual extruders and economically obtain a thermoplastic elastomer by previously forming a specific ethylene-propylene rubber in a granular state and mixing the granulated rubber with an olefinic resin at a specific temperature or above in the extruder. SOLUTION: (A) Ethylene-propylene rubber having high Mooney viscosity, preferably containing a mineral oil in 10-150 pts.wt. based on 100 pts.wt. ethylene-propylene rubber, preferably having 63-75 wt.% high ethylene content is previously formed in granular state and (B) the granulated rubber is mixed with an olefinic resin such as polyethylene at a melting temperature or above of the component B by using an extruder to provide the objective elastomer. The mixing ratio of the component A with the component B is preferably 15-70% component B to 85-30% component A not containing the mineral oil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a thermoplastic elastomer, and more particularly, to a method for producing an olefin-based thermoplastic elastomer.

[0002]

2. Description of the Related Art Generally, ethylene-propylene rubber does not exhibit practical mechanical properties unless added with a reinforcing agent such as carbon black and vulcanized or crosslinked with sulfur or an organic peroxide. However, the vulcanized product and the crosslinked product do not have thermoplasticity, and therefore require a troublesome processing step, and further have a drawback that they cannot be recycled.

[0003] For this purpose, thermoplastic elastomers obtained by adding an olefin resin to ethylene-propylene rubber to impart thermoplasticity have been commercialized. Japanese Patent Publication No. Sho 53-34210 discloses a method in which an olefin resin is added to an ethylene-propylene rubber and the thermoplastic resin and rubber mechanical properties are imparted by lightly crosslinking the resin. Furthermore, a method for producing an olefin-based thermoplastic elastomer in which fluidity is improved by dynamically heat-treating a mixture of an ethylene-propylene rubber and an olefin-based resin with a mineral oil-based softener in the presence of an organic peroxide. Is disclosed in JP-B-56-15741.

[0004]

As described above, it is known to produce a thermoplastic elastomer having thermoplasticity and rubber-like mechanical properties from an ethylene-propylene rubber and an olefin resin. Performance improvements are also known. However, ethylene-propylene rubber is easily blocked, and particularly those containing mineral oil are more remarkably blocked, and are therefore commercially available in a veil form. Ethylene-propylene rubber containing such a massive mineral oil cannot be easily mixed with pelletized olefin-based resin, and cannot be handled by a usual resin extruder because it cannot be supplied to a feed port.

[0005] For this reason, it is necessary to mix using a mixer such as a Banbury mixer or a kneader into which a lump can be put. However, these systems are not economical because they are batch systems and the pellet process is a separate process.

[0006] There is a method of using a special continuous mixer in which a mixer and an extruder capable of introducing a lump are combined, but this mixer is not common.

An object of the present invention is to solve the above-mentioned problems and to provide a method for producing a thermoplastic resin in which an olefin-based thermoplastic elastomer containing mineral oil is economically produced by an ordinary resin extruder. And

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises a step of pre-granulating an ethylene-propylene rubber having a high ethylene content and a high Mooney viscosity containing a mineral oil, and obtaining the obtained granules. The ethylene-propylene rubber and the olefin resin are mixed by an extruder at a temperature not lower than the melting temperature of the olefin resin.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the process for producing a thermoplastic resin according to the present invention, an ethylene-propylene rubber having a high ethylene content and a high Mooney viscosity containing mineral oil is granulated in advance, and the obtained granular ethylene-propylene rubber is obtained. And the olefin resin are mixed by an extruder at a temperature not lower than the melting temperature of the olefin resin.

When an ethylene-propylene rubber having a high ethylene content and a high Mooney viscosity is used as the ethylene-propylene rubber, pellets of the ethylene-propylene rubber having no blocking even when the ethylene-propylene rubber contains a mineral oil can be obtained. . These pellets can be easily mixed with the olefin resin by a usual extruder.

As the ethylene-propylene rubber in the present invention, a copolymer of ethylene and propylene and / or an ethylene-propylene-nonconjugated diene copolymer is preferable, wherein the nonconjugated diene is ethylidene norbornene,
Refers to dicyclopentadiene, 1,4-hexadiene and the like.

In the above ethylene-propylene rubber,
The ethylene content is 63-75% by weight, preferably 6% by weight.
5 to 73% by weight. When the content is less than 63% by weight, blocking tends to occur, and the particles cannot be maintained. If it exceeds 75% by weight, the viscosity of the copolymer-containing solution at the time of producing the ethylene-propylene rubber becomes high, and the production of the ethylene-propylene rubber becomes difficult.

Since the Mooney viscosity of ethylene-propylene rubber is difficult to measure when it is 100 or more, the Mooney viscosity at 100 ° C. (ML1) measured by adding 15 parts by weight of mineral oil to 100 parts by weight of ethylene-propylene. +4)
Displayed with. The Mooney viscosity is 60 or more, preferably 70 or more. When it is less than 60, even if an ethylene-propylene rubber having a high ethylene content is used, blocking tends to occur when a high load is applied.

The mineral oil in the present invention is a high-boiling petroleum fraction usually used for improving the processability of rubber, and the mineral oil is 1 to 100 parts by weight of ethylene-propylene rubber.
0 to 150 parts by weight can be added. When the amount is less than 10 parts by weight, the amount of the mineral oil cannot be 3% by weight, which is necessary for improving the processability described later, based on the total of the ethylene-propylene rubber and the olefin-based resin. If the amount exceeds 151 parts by weight, the particulate matter blocks.

The ethylene-propylene rubber premixed with the mineral oil can be obtained by directly adding the mineral oil to the ethylene-propylene rubber using an open roll or a Banbury mixer. Or, since ethylene-propylene rubber is polymerized in an organic solvent such as hexane, it is more economical to use an oil-extended ethylene-propylene rubber obtained by adding a mineral oil into this polymerization solution. .

The amount of mineral oil added is 3 to 30% by weight, preferably 5 to 25% by weight, based on the total of the ethylene-propylene rubber and the olefin resin. When the amount is less than 3% by weight, there is no effect of improving the workability, and when it exceeds 30% by weight, the mechanical strength is greatly reduced, and it is not practical.

The olefin resin in the present invention is polyethylene, polypropylene, propylene-α-olefin copolymer, or a mixture thereof.
5 ℃ melt flow rate (ASTM-D1238)
To 40 are preferred.

The mixing ratio of the ethylene-propylene rubber and the olefin resin is 85 to 30% by weight (preferably 80 to 35%) of the ethylene-propylene rubber containing no mineral oil.
15 to 70% by weight of the olefin resin
(Preferably 20 to 65% by weight). When the olefin-based resin is less than 15% by weight, mechanical strength sufficient for practical use cannot be obtained, and when it exceeds 70% by weight, the flexibility as rubber is lost.

In the present invention, an ordinary extruder used for polyethylene or polypropylene can be used as a mixing device.

The addition of additives such as heat stabilizers, UV absorbers or carbon black conventionally used in rubbers and plastics has no effect on the effects of the present invention. Further, for example, a small amount of an organic peroxide of 0.1 to 0.5% by weight based on the total of the ethylene-propylene rubber and the olefin-based resin may be added and lightly crosslinked to the extent that the thermoplasticity is not lost. Good.

The crosslinking agent can be applied to the ethylene-propylene rubber and the olefin resin when the granular ethylene-propylene rubber and the olefin resin are mixed with a Henschel mixer or a blender. Alternatively, a crosslinking agent can be added when the mineral oil is mixed with an ethylene-propylene rubber having a high ethylene content and a high Mooney viscosity by an open roll, a Banbury mixer, or the like. In this case, since the mixing of the ethylene-propylene rubber and the mineral oil can be performed at a low temperature, the crosslinking agent does not react during the mixing. For this reason, a mixture of granular ethylene-propylene rubber and olefin resin can be easily processed by an extruder.

[0022]

Embodiments of the present invention will be described below.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

(Examples 1 to 3 and Comparative Examples 1 to 4) As shown in Table 4 below, Examples 1 to 3 and Comparative Examples 1 to 3
In the above, ethylene-propylene rubber (Keltan 708 × 15, Mitsui EPT3072E, Keltan 50
9x100, Keltan 520, Mitsui EPT3095, Keltan 512x50) were pressed into a sheet having a thickness of 2 mm, and cut into pieces with scissors to form pellets of 3 mm square. In Comparative Example 4, Mooney viscosity (ML1 + 4,100
C) 68 ethylene-propylene rubber (Keltan 57
To 8), 15 parts by weight of the above mineral oil was added by an open roll. The Mooney viscosity of the ethylene-propylene rubber to which the mineral oil has been added is 35. This ethylene-propylene rubber was similarly pressed into a sheet and formed into square pellets. Pellet formed as above 88 mm inside diameter
And a load of 8 kg was applied. This load is
1. When stacked on a pallet of 110 × 110 cm.
Equivalent to 6 tons.

When the pellets were left for one week in an atmosphere of 25 ° C. while applying a load as described above, Comparative Examples 1 and 2, which were ethylene-propylene rubbers having a low ethylene content, were obtained.
In and 3, the pellets were agglomerated. In Comparative Example 4, which was an ethylene-propylene rubber having a high ethylene content but a low Mooney viscosity, the pellets did not clump, but blocking between the pellets was observed. In Examples 1 to 3, which are ethylene-propylene rubbers having a high ethylene content and a high Mooney viscosity, no blocking was observed, and the same state as before the load was applied was maintained.

[0028]

[Table 4]

(Examples 4 to 7 and Comparative Examples 5 and 6) As shown in Table 5 below, ethylene-propylene rubber (Keltan 578, Keltan 708 ×) having no blocking, high ethylene content, and high Mooney viscosity was used. 15, Keltan 509 × 100) into pellets using an MS-type feeder ruder (biaxially different-direction rotary ruder, pellet cooling: air cooling) manufactured by Moriyama Co., Ltd.
0, Mirason 11P) and additives were mixed in a Henschel mixer and passed through a 230 ° C. extruder. The results obtained are as shown in Table 5. Comparative Example 5 with Mineral Oil
Had low fluidity and poor processability. Comparative Example 6, which contained a large amount of mineral oil, had good fluidity, but had low mechanical strength and was not practical. Example 4-
No. 7 was practically usable.

[0030]

[Table 5]

[0031]

As described above in detail, according to the present invention, an ethylene-propylene rubber having a high ethylene content and a high Mooney viscosity containing a mineral oil is granulated in advance, and the obtained granular ethylene-propylene rubber is obtained. By mixing the rubber and the olefin resin with an extruder at a temperature not lower than the melting temperature of the olefin resin, a thermoplastic elastomer can be economically produced. Therefore, according to the present invention, ethylene-propylene rubber is easily blocked, and those containing mineral oil are particularly easily blocked, and it is difficult to form pellets. Can be solved.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI theme coat ゛ (reference) C08L 91/00 C08L 91/00 F term (reference) 4F070 AA13 AA15 AA16 AC94 AE02 FA01 FA14 FA17 FB06 FC05 4J002 AE05Y BB03X BB12X BB14X BB15W

Claims (5)

[Claims] 1. An ethylene-propylene rubber having a high ethylene content and a high Mooney viscosity containing mineral oil is granulated in advance, and the obtained granular ethylene-propylene rubber and olefin resin are melted at a melting temperature of the olefin resin. A method for producing a thermoplastic elastomer, comprising mixing with an extruder as described above. 2. The ethylene-propylene rubber contains 63 to 75% by weight of ethylene, and has a Mooney viscosity of 100 ° C. measured by adding 15 parts by weight of a mineral oil to 100 parts by weight of the ethylene-propylene rubber. Mooney viscosity (ML1 + 4) is 60 or more, and 10 to 150 mineral oil is added to 100 parts by weight of ethylene-propylene rubber.
The method for producing a thermoplastic elastomer according to claim 1, wherein the rubber is ethylene-propylene rubber containing parts by weight. 3. The method for producing a thermoplastic elastomer according to claim 1, wherein the olefin-based resin is polyethylene, polypropylene, propylene-α-olefin copolymer, or a mixture thereof. 4. The mixing ratio of the ethylene-propylene rubber and the olefin resin is such that ethylene-propylene rubber does not contain mineral oil.
The method for producing a thermoplastic elastomer according to any one of claims 1 to 3, wherein the olefin resin is 15 to 70% by weight based on 85 to 30% by weight of the propylene rubber. 5. The thermoplastic resin according to claim 1, wherein the content of the mineral oil is 3 to 30% by weight based on the total amount of the ethylene-propylene rubber and the olefin resin. A method for producing an elastomer.