JP2967443B2 - Crosslinking agent for thermoplastic elastomer and method for producing thermoplastic elastomer using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crosslinking agent for a thermoplastic elastomer and a method for producing a dynamically crosslinked thermoplastic elastomer having excellent mechanical properties, heat resistance and moldability using the same.

[0002]

2. Description of the Related Art Elastomer is a general term for a material having rubber elasticity, and has been widely used for automobile tires, industrial and industrial parts, and the like. It has long been known that vulcanization or cross-linking using sulfur, an organic peroxide or the like is performed for improving the mechanical properties and heat resistance of the elastomer.

[0003] In the case of an elastomer, the molding process is complicated with kneading, molding (preliminary molding), vulcanization or cross-linking of a rubber. Has been requested.

[0004] A thermoplastic elastomer (hereinafter abbreviated as TPE) is a blend of an elastomer component and a plastic component. Like an elastomer, it is an elastic material at room temperature but has fluidity at a molding temperature. In one step, molding is possible.

Further, TPE has an advantage that it can be regenerated, and so far, styrene-based TPE and ester-based TP
Many TPEs such as E, amide-based TPE, and olefin-based TPE have been put into practical use. However, TPE is inferior in heat resistance due to its thermoplasticity. In order to improve the heat resistance, the TPE is vulcanized or cross-linked (dynamic vulcanization or Called dynamic crosslinking)
It has been suggested to do so.

In particular, in the field of olefin-based TPE, heat resistance has been improved by dynamic vulcanization or dynamic crosslinking,
The technique is described in, for example, US Pat. No. 4,031,169 (197).
7 years) and U.S. Pat. No. 4,104,210 (1978), and are widely applied. This dynamically crosslinked TPE has somewhat improved heat resistance and mechanical properties as compared to non-crosslinked TPE.

[0007]

The TPE dynamically cross-linked using an organic peroxide as a cross-linking agent is not satisfactory, although its heat resistance and mechanical properties are improved as compared with non-cross-linked TPE. Increasing the amount of organic peroxide increases the degree of crosslinking and improves heat resistance, but decreases mechanical properties,
Moldability also deteriorates.

For example, in the case of an olefin-based TPE, the effect of dynamic crosslinking by an organic peroxide is small, and the mechanical properties of the obtained dynamically crosslinked TPE are not sufficient for practical use.

In the case of an elastomer having a low crosslinking efficiency, such as ethylene propylene rubber (hereinafter abbreviated as EPM) or ethylene propylene diene rubber (hereinafter abbreviated as EPDM),
It is possible to improve heat resistance and mechanical properties by dynamically crosslinking organic peroxide together with a crosslinking aid, but the composition becomes complicated and the level of mechanical properties is sufficient. However, there is a drawback that the moldability deteriorates.
No method has been found for producing a dynamically crosslinked TPE having excellent mechanical properties and heat resistance and good moldability.

[0010] That is, an object of the present invention is to provide a method for producing a dynamically crosslinked TPE having excellent mechanical properties and heat resistance and good moldability, and a crosslinking agent used therefor.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, it has been found that 1- (2-tert-butylperoxyisopropyl) -3-Isopropenylbenzene is an excellent effect not found in conventional organic peroxides, that is, a dynamically crosslinked T having excellent mechanical properties and heat resistance and excellent moldability.
They have found that PE can be obtained, and have reached the present invention.

That is, the present invention provides a crosslinking agent for TPE comprising 1.1- (2-tert-butylperoxyisopropyl) -3-isopropenylbenzene. 2. A method for producing TPE, wherein dynamic crosslinking is performed using 1- (2-tert-butylperoxyisopropyl) -3-isopropenylbenzene as a crosslinking agent. About.

The elastomer component used in the TPE of the present invention is not limited as long as it can be crosslinked with an organic peroxide. For example, EPM, EPDM, butadiene rubber (hereinafter abbreviated as BR), acrylonitrile butadiene rubber, isoprene rubber, Styrene butadiene rubber, chloroprene rubber, hydrogenated nitrile rubber, chlorinated polyethylene and the like can be mentioned.

The plastic component used in the TPE of the present invention is not particularly limited as long as it is a thermoplastic, but a polyolefin-based thermoplastic is preferred. As polyolefin-based thermoplastics,
For example, polyethylene, polypropylene (hereinafter abbreviated as PP), ethylene propylene block copolymer (hereinafter referred to as EP)
Block copolymer), ethylene-vinyl acetate copolymer, ethylene-α-olefin copolymer, olefin vinyl alcohol copolymer, polybutylene, polymethylpentene (hereinafter abbreviated as TPX) and the like.

The blend ratio of the elastomer component and the plastic component used in the TPE of the present invention is usually 10 to 90 parts by weight of the elastomer component and 90 parts by weight of the plastic component.
It can vary widely from 10 to 10 parts by weight, but preferably from 80 to 30 parts by weight of the plastic component to 20 to 70 parts by weight of the elastomer component.

The amount of 1- (2-tert-butylperoxyisopropyl) -3-isopropenylbenzene used in the TPE of the present invention is usually 0.1 to 5 phr, preferably 0.1 to 5 phr, per 100 g of TPE. 4-3phr
It is.

The crosslinking agent for TPE of the present invention, 1- (2-
Tertiary butyl peroxyisopropyl) -3-isopropenylbenzene may be used as it is in an industrially pure form, or calcium carbonate, silica, clay, adsorptive silica, zeolite, etc. to facilitate uniform dispersion in TPE. May be used.

For the production of the TPE of the present invention, various internal closed type mixers such as a Banbury mixer, a pressurized kneader, a kneader blender, a continuous kneader, an extruder, a transfer mixer, an injection molding machine, etc., or an open roll mill Etc. can be used. The kneading and dynamic crosslinking of the TPE are performed under conditions where the elastomer component and the plastic component are sufficiently blended.

The kneading temperature varies depending on the desired TPE elastomer component and plastic component, but is generally from 130 to 250 ° C, preferably from 150 to 200 ° C. The kneading time depends on the kneading temperature, but is usually 1 to 40 minutes, preferably 3 to 20 minutes.

In producing the TPE of the present invention, extender oils such as paraffin oil, antioxidants such as 2,6-di-tert-butyl-4-methylphenol, stearic acid and zinc stearate are also used. Lubricants, such as
Fillers such as carbon black and calcium carbonate, pigments and the like can be used as required.

As an apparatus for continuous production such as an extruder, for example, an apparatus described in Japanese Patent Publication No. 48-5194 is useful. The apparatus described in Japanese Patent Publication No. 48-5194 is for continuously kneading and dynamically crosslinking by injecting a crosslinking agent in the middle of a cylinder of a single screw extruder. When used, 1- (2-
Dynamic cross-linking with tertiary butyl peroxyisopropyl) -3-isopropenylbenzene can be performed in one step, so that labor saving in the production process and reduction in production cost are possible.

[0022]

When TPE is dynamically cross-linked using 1- (2-tert-butylperoxyisopropyl) -3-isopropenylbenzene as a cross-linking agent, the phase of the elastomer component and the plastic component is increased due to the presence of the isopropenyl group. The solubilization is promoted, and a dynamically crosslinked TPE excellent in mechanical properties, heat resistance and moldability can be obtained.

[0023]

EXAMPLES Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the following Examples and Comparative Examples do not limit the present invention.

Examples 1 to 5 and Comparative Examples 1 to 9
Heat to 80 ° C and add PP (Vestolen P5200, H ｛ls
And DPM (Dutral CO-034, propylene content 30% Mooney viscosity ML1 + 4 100 ° C. = 40, Mo
ntepolimeri) at the ratio shown in Table 1, and kneaded at a rotor rotation speed of 30 rpm. And Table-1
Was added in a predetermined amount, and kneading was continued for 10 minutes to produce a dynamically crosslinked TPE.

For the comparative example, a system in which a crosslinking aid was used in combination with an organic peroxide was also used. The obtained TPE was press-molded in a mold having a thickness of 1 mm, and the tensile strength and elongation were measured according to ISO.
It was measured according to R37. Further, in order to determine the degree of crosslinking of TPE, the insoluble content (gel fraction) in boiling xylene was measured. The results are summarized in Table 1.

Organic peroxide and crosslinking aid D-120: 1- (2-tert-butylperoxyisopropyl) -3-isopropenylbenzene Px14: 1,3-bis- (tert-butyl) shown in Table 1 Peroxyisopropyl) benzene AD: 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane Plk400: Trimethylolpropane trimethacrylate Plk401: Ethylene glycol dimethacrylate (all manufactured by Kayaku Akzo)

Table 1 Example 1 2 3 4 4 5 5 PP (phr) 40 40 50 30 60 EPM (phr) 60 60 50 70 40 Organic peroxide D-120 D-120 D-120 D-120 D-120 Addition Amount (phr) 0.90 1.35 0.90 0.90 0.90 Tensile strength (MPa) 12.0 17.0 14.0 4.5 13.0 Elongation (%) 430 468 405 71 450 Gel Fraction (%) 47 53 43 80 40

Comparative Example 12 34 PP (phr) 40 50 30 60 EPM (phr) 60 50 70 40 Organic peroxide None None None None Addition amount (phr) Tensile strength (MPa) 4.1 3.2 1.0 5.0 Elongation (%) 85 60 10 42 Gel fraction (%) 00 00

Comparative Example 5 67 8 89 PP (phr) 40 40 40 50 50 EPM (phr) 60 60 60 50 50 Organic peroxide Px14 AD Px14 AD AD Addition amount (phr) 0.48 0.78 48 0.8 0.8 Crosslinking aid None None PlK400 None Plk401 Addition amount (phr) 1.0 1.0 Tensile strength (MPa) 7.0 6.0 8.2 5.2 7.0 Elongation (% ) 167 150 269 135 240 Gel fraction (%) 35 32 37 30 37

Examples 6 to 8 and Comparative Examples 10 to 12 EPM, EPDM and PP were used as shown in Table 2, and the same operations as in Examples 1 to 5 and Comparative Examples 1 to 9 were performed. The results are summarized in Table 2.

The elastomers, plastics and organic peroxides shown in Table 2 Vestolen P5200: polypropylene, Hostalen PPU 180P manufactured by HHls, Inc .: polypropylene, H ｛ch
Dutral CO-034 manufactured by st Co .: EPM, propylene content 30
%, Mooney viscosity ML1 + 4 100 ° C = 40, Montepolim
eri Vistalon 404: EPM, 60% propylene content,
Exxon Chemicals Keltan 520: EPDM, propylene content 40%,
Dicyclopentadiene content 4.5%, DCP manufactured by DSM: dicumyl peroxide, D-120 manufactured by Kayaku Akzo, Px14, and AD are the same as those shown in Table 1.

Table 2 Example Comparative Example 6 7 8 10 11 12 Vestolen P5200 (phr) 40 40 40 40 Hostalen PPU 180p (phr) 40 40 Dutral CO-034 (phr) 60 30 60 30 Vistalon 404 (phr) 60 60 Keltan 520 (phr) 30 30 Organic peroxide D-120 D-120 D-120 Px14 DCP AD loading (phr) 1.32 1.32 1.35 0.54 0.86 0.93 Tensile strength (MPa) 7.8 15.0 13.0 3.9 6.0 7.2 Elongation (%) 391 448 393 88 120 170 Gel fraction (%) 62 72 68 30 37 35

From the results shown in Tables 1 and 2, 1- (2-
TPE dynamically crosslinked using tertiary butylperoxyisopropyl) -3-isopropenylbenzene,
It is clear that its mechanical properties are excellent.

Examples 9 to 14 and Comparative Examples 13 to 16 Zone A of an extruder provided with an injection port in the middle of a cylinder (from the hopper to the crosslinker injection port) described in JP-B-48-5194. Part) to 180 ° C,
Further, zone B (the portion from the injection port to the die) was adjusted to the temperature shown in Table 3.

From the hopper, an EP block copolymer (ethylene propylene block copolymer, Nobrene BC-
3, Mitsubishi Yuka Co., Ltd.) and BR (Buna CB10, Mooney viscosity ML1 + 4 100 ° C = 47, cis 1,4 bond 96)
%, Manufactured by Bayer AG), and kneading was started. A predetermined amount of 0.5 phr of a polymer of an antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline (Flectol H, manufactured by Monsanto Co.) and an organic peroxide shown in Table 3 were injected through an injection port in the middle of the cylinder. In addition, dynamic crosslinking was performed by an extruder under the conditions shown in Table 3.

The obtained TPE was press-molded in a mold having a thickness of 1 mm, and its tensile strength and elongation were measured in accordance with DIN 53504. In order to evaluate the moldability of TPE, the melt flow rate (hereinafter abbreviated as MFR) was set to 230 ° C.,
It was measured under the condition of 0 kg. The results are summarized in Table 3.

Table 3 Example 9 10 11 12 13 14 EP block copolymer (phr) 80 70 70 60 60 50 BR (phr) 20 30 30 40 40 50 Organic peroxide D-120 D-120 D-120 D-120 D-120 D-120 Addition amount (phr) 1.0 1.0 0.8 0.8 0.8 0.8 Kneading extrusion temperature (℃) 185 185 175 185 190 185 Kneading extrusion time (min) 8 8 18 8 6 8 Tensile strength (MPa) 19.3 19.0 20.0 16.4 15.7 15.1 Elongation (%) 305 330 335 353 362 369 MFR (g / 10min) 45 43 44 40 41 37

Comparative Example 13 14 15 16 EP block copolymer (phr) 80 70 60 50 BR (phr) 20 30 40 50 Organic peroxide Px14 Px14 DCP DCP addition amount (phr) 0.5 0.50. 8 0.8 Kneading and extrusion temperature (° C.) 190 180 190 180 Kneading and extrusion time (minutes) 5 848 Tensile strength (MPa) 17.5 16.8 12.9 11.6 Elongation (%) 200 265 305 310 MFR (g / 10 minutes) 11 10 7 5

From the results shown in Table 3, the T produced according to the present invention was obtained.
It is clear that PE has excellent mechanical properties and excellent moldability.

Examples 15 to 20, Comparative Examples 17 to 20 PP (Vestolen P5200, manufactured by Hells) and E were placed in a chamber of a Brabender mixer preheated to 150 ° C.
PDM (Keltan 520, manufactured by DSM) was charged at the ratio shown in Table 4 and kneaded at a rotor rotation speed of 45 rpm for 8 minutes. Thereafter, a predetermined amount of the organic peroxide shown in Table 4 was added, and kneading was continued for 15 minutes to produce a dynamically crosslinked TPE. The obtained TPE is press-molded in a mold having a thickness of 1 mm,
Tensile strength and elongation were measured according to ISO R37. In order to evaluate the heat resistance, the compression set was determined according to ASTM D3.
According to the 95B method, the measurement was carried out at 70 ° C. and 24 hrs. Further, the MFR was measured under the conditions of 230 ° C. and 10 kg. The results are summarized in Table 4.

Table 4 Example 15 16 17 18 19 20 20 PP (phr) 40 40 50 50 60 60 EPDM (phr) 60 60 50 50 40 40 Organic peroxide D-120 D-120 D-120 D-120 D -120 D-120 Amount (phr) 1.3 1.7 1.2 1.5 1.0 1.3 Tensile strength (MPa) 16.2 15.0 17.8 17.0 18.0 17.7 Elongation (%) 450 409 463 423 481 478 Compression set (%) 45 42 47 44 49 48 MFR (g / 10min) 3.0 8.2 5.2 10.1 7.9 19.6

Comparative Example 17 18 19 20 PP (phr) 40 40 50 60 EPDM (phr) 60 60 50 40 Organic peroxide Px14 Px14 AD AD Addition amount (phr) 0.7 1.0 1.3 1.3 Tensile strength (MPa) 14.0 11.5 13.8 16.1 Elongation (%) 385 300 365 398 Compression set (%) 50 46 58 62 MFR (g / 10 min) 2.3 1.5 3 4.0 4.1

Examples 21 to 25 and Comparative Examples 21 to 24 TPX (RT-20, melting point 230 ° C., MFR) was placed in a chamber of a Brabender mixer preheated to 200 ° C.
= 26, manufactured by Mitsui Petrochemical Co., Ltd.) and EPDM (Mitsui EPT)
3045, Mooney viscosity ML1 + 4 100 ° C. = 38, manufactured by Mitsui Petrochemical Co., Ltd.) at the ratio shown in Table 5, and kneaded at a rotor rotation speed of 50 rpm for 5 minutes. And 2,
6-Di-tert-butyl-4-methylphenol (antioxidant, Sumilizer BHT, manufactured by Sumitomo Chemical Co., Ltd.)
After adding 5 phr, a predetermined amount of the organic peroxide shown in Table 5 was added, and kneading was further continued for 15 minutes to produce a dynamically crosslinked TPE.

The obtained TPE was press-molded in a mold having a thickness of 1 mm, and its tensile strength and elongation were measured in accordance with ISO R37. The compression set was measured at 70 ° C. and 24 hrs according to ASTM D395B method. Also MF
R was measured under the conditions of 260 ° C. and 5 kg. The results are summarized in Table 5.

Table 5 Example 21 22 23 24 25 25 TPX (phr) 40 40 50 60 70 EPDM (phr) 60 60 50 40 30 Organic peroxide D-120 D-120 D-120 D-120 D-120 Addition Amount (phr) 1.2 1.6 1.5 1.5 1.5 Tensile strength (MPa) 17.8 17.0 18.8 19.3 20.1 Elongation (%) 468 434 476 480 431 Compression set (%) 38 36 36 34 31 MFR (g / 10 min) 30 44 34 37 42

Comparative Example 21 22 23 24 TPX (phr) 40 50 60 70 EPDM (phr) 60 50 40 30 Organic peroxide YD1) YD YD YD Addition amount (phr) 0.9 0.9 0.9 0.9. 9 Tensile strength (MPa) 13.1 13.7 14.3 15.0 Elongation (%) 401 413 419 372 Compression set (%) 49 47 46 42 MFR (g / 10 min) 16 17 19 22

1) YD: 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexyne-3
(Manufactured by Kayaku Akzo)

From the results in Tables 4 and 5, it is clear that the TPE produced according to the present invention is excellent not only in mechanical properties but also in moldability and heat resistance.

[0049]

The TPE obtained according to the present invention has excellent mechanical properties, heat resistance and moldability, and can be used in the field of industrial goods and automobile parts which have been difficult to use in the past. . Therefore, its industrial value is great.

Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) C08L 7/00-21/02 C08J 3/24 C08K 5/14 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. A 1- (2-tert - butyl peroxy isopropyl) -3-thermoplastic elastomer, characterized in that it comprises a diisopropenylbenzene (elastomer formed
And a plastic component) . 2. An elastomer component and a plastic component using 1- (2-tert-butylperoxyisopropyl) -3-isopropenylbenzene as a crosslinking agent.
A method for producing a thermoplastic elastomer, comprising dynamically crosslinking a blend of the above . "