JP2582856B2 - Method for producing thermoplastic elastomer sheet - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a thermoplastic elastomer sheet, and more particularly, to a method for producing a thermoplastic elastomer sheet capable of simplifying the production process.

TECHNICAL BACKGROUND OF THE INVENTION Thermoplastic elastomers have been widely used as automotive parts such as bumper parts, instrument panels, interior sheets, golf club grips, swimming fins and the like. This thermoplastic elastomer is
It has properties of both thermoplasticity and elasticity, and can be formed into a molded article excellent in heat resistance, tensile properties, weather resistance, flexibility and elasticity by injection molding, extrusion molding or the like.

As such a thermoplastic elastomer, for example, JP-B-53-34210 discloses that a 60-80 parts by weight of a monoolefin copolymer rubber and a 40-20 parts by weight of a polyolefin resin are dynamically partially cured. A thermoplastic elastomer is disclosed. Also, Japanese Patent Publication No. 53-21021,
A thermoplastic elastomer comprising (a) a partially crosslinked copolymer rubber comprising an ethylene-propylene-non-conjugated polyene copolymer rubber and having a gel content of 30 to 90% by weight, and (b) a polyolefin resin is disclosed. I have. Furthermore, Japanese Patent Publication No. 55-18448 discloses a thermoplastic elastomer in which an ethylene-propylene copolymer rubber and a polyolefin resin are dynamically partially or completely crosslinked.

By the way, conventional thermoplastic elastomers as described above,
Usually, it has been manufactured by kneading and crosslinking a peroxide-crosslinked polyolefin-based copolymer rubber, a peroxide-crosslinked polyolefin resin, and a peroxide-decomposed polyolefin resin in a molten state in the presence of an organic peroxide. Such a crosslinking reaction is complicated,
In order to produce a uniformly crosslinked thermoplastic elastomer, conventionally, the crosslinking reaction is completely terminated in a twin-screw extruder, and then the obtained thermoplastic elastomer is mixed with one another. It was shaped into a pellet.
And this thermoplastic elastomer in pellet form is
A sheet made of a thermoplastic elastomer has been manufactured by molding into a sheet shape using a die or the like.

An object of the present invention is to provide a method for manufacturing a sheet made of a thermoplastic elastomer, which can save energy and greatly simplify the manufacturing process.

SUMMARY OF THE INVENTION The method for producing a thermoplastic elastomer sheet according to the present invention comprises the following steps: (a) peroxide-crosslinked olefin copolymer rubber 60
To 20 parts by weight, (b) 20 to 65 parts by weight of a peroxide crosslinked polyethylene resin, (c) 40 to 15 parts by weight of a peroxide decomposable polypropylene resin (where (a) + (b) +
(C) is adjusted to 100 parts by weight), (e) a mineral oil-based softener and (d) an organic peroxide are mixed in a non-molten state, and the resulting mixture is fed to a twin-screw extruder. In the twin-screw extruder, the mixture is heated to 170 to 240 ° C. and kneaded in a molten state for 1 to 10 minutes to partially or completely crosslink to prepare a thermoplastic elastomer, and then obtain the obtained thermoplastic elastomer in a molten state. Is formed into a sheet directly from a T-die device connected to the twin-screw extruder in a molten state.

In the method for producing a thermoplastic elastomer sheet according to the present invention, each of the components (a), (b), (c), and
After mixing (e) and (d) in a non-molten state, the resulting mixture is fed to a twin-screw extruder and
Heated to about 240 ° C. and kneaded in a molten state for 1 to 10 minutes to partially or completely crosslink to prepare a thermoplastic elastomer. Then, the obtained thermoplastic elastomer in a molten state Since it is formed into a sheet from a T-die device connected to the extruder, a pelletizing process,
The step of drying the pellets and the step of re-melting the pellets can be omitted, so that energy can be saved, and therefore, the manufacturing process of the sheet can be significantly simplified.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, a method for producing a thermoplastic elastomer sheet according to the present invention will be specifically described.

(A) Peroxide-crosslinked olefin copolymer rubber The (a) peroxide-crosslinked olefin copolymer rubber used in the present invention is an amorphous elastic copolymer containing olefin as a main component, d) a rubber which is mixed with an organic peroxide and kneaded under heating to be crosslinked to reduce the fluidity or to become non-flowable, specifically, an ethylene-propylene copolymer rubber,
Ethylene, such as ethylene-propylene-non-conjugated diene terpolymer or multi-component copolymer rubber, ethylene-butadiene copolymer rubber, ethylene-1-butene copolymer rubber, ethylene-1-butene-non-conjugated diene multipolymer; And carbon number 3
Substantially amorphous copolymer rubbers containing .alpha.-olefins as main components or a mixture thereof are used. Of these, ethylene-propylene copolymer rubber and ethylene-propylene-nonconjugated diene terpolymer rubber are preferred.

Here, the non-conjugated diene is dicyclopentadiene,
It means 1,4-hexadiene, cyclooctadiene, methylene norbornene, 5-ethylidene-2-norbornene and the like. Copolymer or dicyclopentadiene and 5
A quaternary copolymer containing both components of -ethylidene-2-norbornene is preferred.

Mooney viscosity of these binary or multipolymers [ML _{1 + 4}
(100 ° C.)] is usually 10 to 180, preferably 40 to 140, and its iodine value (degree of unsaturation) is preferably 16 or less.

In the present invention, the amount of each composition unit contained in these copolymer rubbers is such that, in the 1-olefin portion, ethylene / unit / α-olefin unit is 90/10 to 50/50, preferably 80/20 to 50/50. A ratio of 60/40 (molar ratio) is particularly desirable. 1-olefin (ethylene + α-olefin) unit / non-conjugated diene unit (in the case of a ternary or multi-component copolymer) is usually 98/2 to 90/10, preferably 97/3 to 94/6 (molar ratio). Is the ratio of

(B) Peroxide-crosslinked polyethylene resin The (b) peroxide-crosslinked polyethylene resin used in the present invention is mixed with (d) an organic peroxide,
A polyethylene resin which is crosslinked by kneading under heating to reduce the fluidity or becomes non-flowable. This polyethylene resin is composed of ethylene and carbon number 4
To 10 and preferably a random copolymer with an α-olefin having 5 to 10 carbon atoms. This random copolymer also includes so-called linear low density polyethylene (LLDPE).

In this random copolymer, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-octene are used as α-olefins having 4 to 10 carbon atoms to be copolymerized with ethylene. -Decene or a mixture of at least two of these, preferably an α-olefin having 5 to 10 carbon atoms, particularly preferably an α-olefin having 6 to 8 carbon atoms, especially 4-methyl-1-pentene. preferable.

In addition, the random copolymer generally has an ethylene content of 90 to 99.5 mol%, preferably 94 to 99 mol%, more preferably 95 to 99 mol%, from the viewpoint of the flexibility and heat resistance of the thermoplastic elastomer. It is desirable to be within the range.

The (b) peroxide-crosslinked polyethylene resin has a melt index (measured at 190 ° C. under a load of 2160 g according to the method of ASTM-D-1238) of 0.01 to 100 g.
/ 10 minutes, preferably 0.1-50 g / 10 minutes, with a density of 0.890
It is desirably 0.970 g / cm ³ , preferably 0.910 to 0.940 g / cm ³ .

(C) Peroxide-decomposable polypropylene-based resin The (c) peroxide-decomposed polypropylene-based resin used in the present invention is mixed with (d) an organic peroxide and kneaded under heating without cross-linking, resulting in reduced fluidity. Rather, it is a polypropylene resin whose molecular weight is reduced by thermal decomposition and its flowability is increased, and specifically, isotactic polypropylene or propylene and other α-olefin of 50 mol% or less, preferably 15 mol% or less. A propylene-ethylene block copolymer,
Propylene-1-butene copolymer, propylene / 1-hexene copolymer, propylene / 1-octene copolymer, propylene / 4-methyl-1-pentene copolymer, propylene / 1-decene copolymer, etc. Is used.

This (c) peroxide decomposable polypropylene resin has a melt index (ASTM D 1238, 230 ° C,
2160 g) is 0.1 to 50 g / 10 min, preferably 5 to 20 g / 10 min.

(D) Organic peroxide In the present invention, a blend comprising (a) a peroxide-crosslinked olefin copolymer rubber, (b) a peroxide-crosslinked polyethylene resin, and (c) a peroxide-decomposable polypropylene resin as described above. Things are (d)
It is dynamically heat treated in the presence of an organic peroxide and is partially or completely crosslinked.

As the above-mentioned organic peroxide, specifically, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexane, 2,5-dimethyl- 2,5-bis (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (t
ert-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, dibenzoyl peroxide, tert-
Butyl peroxybenzoate and the like can be used. Of these, bisperoxide-based compounds are preferred because of their low odor and high scorch stability, especially 1,3
-Bis (tert-butylperoxyisopropyl) benzene is optimal.

In performing partial or complete crosslinking, a crosslinking aid such as p-quinone dioxime, p, p'-dibenzoylquinone dioxime, or divinylbenzene (DVB);
By blending a polyfunctional vinyl monomer such as diethylene glycol methacrylate or polyethylene diglycol methacrylate, a more uniform and gentle crosslinking reaction can be realized. Therefore, it is preferable to blend these crosslinking aids or polyfunctional vinyl monomers. In particular, divinylbenzene (DVB) has a uniform cross-linking effect due to heat treatment,
It is most preferable because a thermoplastic elastomer having a good balance between fluidity and physical properties can be obtained. Divinylbenzene (DV
The compounding amount of B) is 0.05 to 2 parts by weight, preferably 0.1 to 1.5 parts by weight, based on 100 parts by weight of the composition.

Component Ratio The above (a) peroxide-crosslinked olefin copolymer rubber, (b) peroxide-crosslinked polyethylene resin and (c) peroxide-decomposed polypropylene resin are blended in the following amounts, respectively. Is preferred.

(A) Peroxide-crosslinked olefin copolymer rubber 80
(B) 10-80 parts by weight, preferably 20-65 parts by weight, of peroxide-crosslinked polyethylene resin (c) 50-10 parts by weight of peroxide-decomposable polypropylene resin
Parts by weight, preferably 40 to 15 parts by weight Here, the above components (a), (b) and (c) are present in an amount such that the total is 100 parts by weight.

Optional Components In the present invention, a blend comprising (a) a peroxide-crosslinked olefin copolymer rubber, (b) a peroxide-crosslinked polyethylene resin and (c) a peroxide-decomposed polypropylene resin as described above, (D)
In preparing a thermoplastic elastomer composition by partially or completely cross-linking by dynamically heat-treating in the presence of an organic peroxide, (e) a mineral oil-based softening agent may be added to the above blend if necessary. You can keep it.

(E) Mineral oil-based softeners usually reduce the intermolecular force of rubber when rolling rubber to facilitate the processing, assist dispersion of carbon black, white carbon, etc., or vulcanized rubber. A high-boiling petroleum fraction used for the purpose of decreasing the hardness of the resin and increasing its flexibility or elasticity is used.Specifically, a mineral oil such as a paraffinic, naphthenic, or aromatic oil is used. Can be

Such a mineral oil-based softener (e) comprises the component (a),
It is used in an amount of 50% by weight or less, preferably 20% by weight or less of the total weight of (b) and (c).

This (e) mineral oil-based softener comprises the above components (a) and (b)
And (c), or may be previously added to component (a).

In the above blend, if necessary, a filler,
A coloring agent, an antioxidant, an antioxidant, a light or light fast stabilizer, a processing aid, an antistatic agent, and other physical property improving agents may be added.

These fillers and the like may be blended in the blend as described above, but in some cases, the components (a),
(B) and (c) can also be blended after being crosslinked by dynamic heat treatment in the presence of (d) an organic peroxide.

Such a filler or the like is used in an amount of 50% by weight or less, preferably 35% by weight or less of the total weight of the above components (a), (b) and (c).

As the filler, specifically, carbon black, clay, talc, calcium carbonate, heavy calcium carbonate,
Kaolin, diatomaceous earth, silica, alumina, asbestos, graphite, glass fiber and the like are used. As antioxidants, phenyl-α-naphthylamine, p-
Amine antioxidants such as isopropoxydiphenylamine, N, N'-diphenylethylenediamine, nonylated diphenylamine, 2,6-ditert-butylphenol, styrenated phenol, butylhydroxyanisole, 4,4'-hydroxydiphenyl, 2 , 2-Methylene-bis- (4-methyl-6-cyclohexylphenol), tetrakis- [methylene-3- (3 ', 5'-ditert-butyl-4'-hydroxyphenyl) propionate] methane, tris- ( A phenolic antioxidant such as 2-methyl-hydroxy-5-di-tert-butylphenyl) butane is used.

(D) To promote the decomposition of organic peroxides, trisethylamine, tributylamine, 2,4,6-
Tertiary amines such as tris (dimethylamine) phenol and aluminum, cobalt, vanadium, copper, calcium, zirconium, manganese, magnesium, lead, mercury, and other organic metal carboxylate such as octanoate It can also be used in the heat treatment step.

Next, each component (a), (b), (c),
A method for producing a thermoplastic elastomer sheet containing (d) and, if necessary, (e) will be described.

First, each component (a), (b), (c),
(D) and (e) if necessary, in a non-molten state, preferably
Drive in at 40 ° C. or lower, more preferably at room temperature. At this time, a Henschel mixer, a tumbler blender or the like is used.

Next, the mixture obtained as described above is fed to a twin-screw extruder, in which the mixture is heated and kneaded in a molten state, and partially or completely crosslinked. To prepare a thermoplastic elastomer in a molten state. The kneading is preferably performed in an atmosphere of an inert gas such as nitrogen or carbon dioxide. The temperature is usually 150 to 280 ° C, preferably 170 to 240 ° C, and the kneading time is usually 1 to 20 minutes.
Preferably, it is 1 to 10 minutes.

In this way, the thermoplastic elastomer in the molten state, which is kneaded in a molten state in the twin-screw extruder and partially or completely crosslinked, is prepared by using a T-die or the like connected to the twin-screw extruder. It is supplied in a molten state to a forming device and is formed into a sheet without pelletization.

A T-die is mainly used as a molding device connected to the twin-screw extruder as described above.

Thus, in the present invention, each component (a) as described above,
After mixing (b), (c), (d) and (e) if necessary in a non-molten state, the resulting mixture is fed to a twin-screw extruder and melted in the twin-screw extruder. A thermoplastic elastomer is prepared by kneading and partially or completely cross-linking to prepare a thermoplastic elastomer. Then, the obtained thermoplastic elastomer in a molten state is kept in a molten state from a molding device connected to the twin-screw extruder to obtain a sheet-like material. It is not necessary to perform a pelletizing step of the thermoplastic elastomer because it is molded into a thermoplastic elastomer. Therefore, the step of drying the pellet and the step of remelting the pellet can be omitted, and energy saving can be achieved. Can be significantly simplified.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Example 1 (i) Ethylene-propylene-dicyclopentadiene copolymer rubber to which paraffin-based process oil was added in an amount of 30% by weight (ethylene content: 77 mol%, iodine value: 6, Mooney viscosity: ML _{1 + 4} ( (100 ° C) 70) 35 parts by weight, (ii) melt index 11, 10 parts by weight of polypropylene having a density of 0.91 g / cm ³ , (iii) melt index 25, 5 parts by weight of polypropylene having a density of 0.91 g / cm ³ , (Iv) 23 parts by weight of a linear low density polyethylene having a melt index of 2 and a density of 0.920 g / cm ³ , and (v) a carbon master batch (low density polyethylene 60).
(Vi) 40 parts by weight of carbon black), (vi) 19 parts by weight of a calcium carbonate masterbatch (20 parts by weight of atactic polypropylene, 80 parts by weight of calcium carbonate), and (vii) a heat stabilizer. 0.15 parts by weight of (Irganox 1010) and (viii) a solution in which 0.1 part by weight of 1,3-bis (tert-butyloxyisopropyl) benzene was dissolved and dispersed in 0.15 part by weight of divinylbenzene were mixed by a tumbler blender. The obtained mixture was attached to a T-die (coat hanger type, length 1400 mm, lip opening 2 mm) with a length of 90 m.
m diameter twin screw extruder (Nippon Steel TEX90, L / D = 32, screw rotation speed: 180 rpm, extruder: 220 kg / hr, screen pack: 40 × 80 × 80 × 40 mesh, cylinder temperature: C ₁ / C ₂ / C ₃
/ C ₄ / C ₅ / C ₆ / D = 150/170/220/200/200/200/230 (℃)) by extruding while melting and kneading the sheet (width 1300m
m, thickness 1.5 mm). Table 1 shows the basic physical properties (tensile properties and tear properties measured by the method of JIS K6301) of the obtained sheet.

Example 2 In Example 1, instead of the ethylene-propylene-dicyclopentadiene copolymer rubber, an ethylene-propylene-ethylidene norbornene copolymer rubber (containing ethylene) was added with a paraffinic process oil in an amount of 30% by weight. Rate 78 mol%, iodine value 13, Mooney viscosity ML _{1 + 4} (1
(00 ° C.) A sheet was obtained and the basic physical properties of the sheet were measured in the same manner as in Example 1 except that 75) was used.

 Table 1 shows the results.

Example 3 (i) Ethylene-propylene-dicyclopentadiene copolymer rubber to which paraffin-based process oil was added in an amount of 30% by weight (ethylene content: 77 mol%, iodine value: 6, Mooney viscosity: ML _{1 + 4} ( (100 ° C) 70) 27 parts by weight; (ii) Melt index (ASTM D 1238, 230 ° C) 11,
8 parts by weight of polypropylene having a density of 0.91 g / cm ³ , (iii) a melt index of 25, 4 parts by weight of polypropylene having a density of 0.91 g / cm ³ , and (iv) a melt index (ASTM D 1238, 190 ° C.) of 2,
31 parts by weight of linear low-density polyethylene having a density of 0.920 g / cm ³ , and (v) a carbon master batch (low-density polyethylene 60
(Vi) 40 parts by weight of carbon black), (vi) 20 parts by weight of a calcium carbonate masterbatch (20 parts by weight of atactic polypropylene and 80 parts by weight of calcium carbonate), and (vii) a heat stabilizer. 0.15 parts by weight of (Irganox 1010) and (viii) a solution in which 0.1 part by weight of 1,3-bis (tert-butyloxyisopropyl) benzene was dissolved and dispersed in 0.15 part by weight of divinylbenzene were mixed by a tumbler blender. The resulting mixture was extruded with a twin screw extruder equipped with a T-die (length: 1400 mm, lip opening: 2 mm) at 220 ° C. while melting and kneading to obtain a sheet (width: 1300 mm, thickness: 1.300 mm).
5 mm), and the basic physical properties of the sheet were measured in the same manner as in Example 1.

 Table 1 shows the results.

Example 4 In Example 1, 2,5-dimethyl 2,5 was used instead of 1,3-bis (tert-butyloxyisopropyl) benzene.
A sheet was obtained in the same manner as in Example 1 except that -di (tert-butylperoxy) hexene-3 was used, and the basic physical properties of the sheet were measured.

 Table 1 shows the results.

Comparative Example 1 In Example 1, a 90 mm diameter 1
Shaft extruder (P-90, L / D = 32, full flight screw, screw rotation speed: 180 rpm, throughput: 220k, manufactured by Nippon Steel Corporation)
g / hr, screen pack: 40 × 80 × 80 × 40 mesh, cylinder _{temperature: C 1 / C 2 / C} 3 / C 4 / C 5 / D = 150/170/220/200/100
/ 230 / (° C.)), and a sheet was obtained in the same manner as in Example 1, and the basic physical properties of the sheet were measured.

 Table 1 shows the results.

From Table 1, it can be seen that the basic physical properties of the thermoplastic elastomer sheet obtained by the production method of the present invention are superior to the basic physical properties of the thermoplastic elastomer sheet obtained by the conventional production method.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shizuo Shimizu 3 Chigusa Coast, Ichihara City, Chiba Prefecture Mitsui Oil Chemical Industry Co., Ltd. (56) References JP-A-60-231748 (JP, A) JP-A-59- 106946 (JP, A)

Claims (1)

(57) [Claims] (1) 60 to 20 parts by weight of a peroxide crosslinked olefin copolymer rubber, (b) 20 to 65 parts by weight of a peroxide crosslinked polyethylene resin, and (c) 40 to 15 parts of a peroxide decomposable polypropylene resin. Parts by weight (where (a)
+ (B) + (c) should be 100 parts by weight),
After mixing (e) a mineral oil-based softener and (d) an organic peroxide in a non-molten state, the obtained mixture is fed to a twin-screw extruder and heated to 170 to 240 ° C in the twin-screw extruder. The thermoplastic elastomer is prepared by partially or completely cross-linking by kneading for 1 to 10 minutes in a molten state to prepare a thermoplastic elastomer, and the obtained thermoplastic elastomer in a molten state is continuously connected to the twin-screw extruder in a molten state. A method for producing a sheet made of a thermoplastic elastomer, wherein the sheet is formed directly from a T-die device.