JPH10139945A5 - - Google Patents

Description

[0004]
[Means for solving the problem]
The present invention provides a thermoplastic resin composition comprising (A) an olefin polymer, (B) a crosslinked styrene polymer having a specific gravity of 0.5 to 1.1 , and (C) (A) at least one block segment selected from (A-1) a styrene polymer block segment and (A-2) a polybutadiene block segment having a 1,2-vinyl bond content of less than 20%, and (B) a hydrogenated block copolymer obtained by hydrogenating 90% or more of the unsaturated double bonds of a block copolymer having a linear or branched block structure, the block copolymer comprising a butadiene (co)polymer block segment having a 1,2-vinyl bond content of 20% or more in the butadiene moiety and/or an isoprene (co)polymer block segment having a vinyl bond content of 10% or more in the isoprene moiety.

[0005]
In the present invention, the olefin polymer constituting component (A) is a polymer having an α-monoolefin having 2 to 8 carbon atoms as the main monomer component. Specific examples of this olefin polymer include low-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-propylene random copolymer, ethylene-propylene block copolymer , polymethylpentene, polybutene-1, etc., which are used alone or in combination of two or more. Particularly preferred olefin polymers are polymers having ethylene or propylene as the main monomer component, specifically various polyethylenes, polypropylene, ethylene-vinyl acetate random copolymer, ethylene-(meth)acrylic acid random copolymer, ethylene-glycidyl methacrylate random copolymer, etc., propylene random or propylene block copolymer, and further mixtures thereof.

[0006]
In the present invention, the cross-linked styrene-based polymer constituting component (ii) is a (co)polymer whose main components are a styrene-based monomer such as styrene, p-methylstyrene, or α-methylstyrene, and a polyfunctional monomer such as divinylbenzene or a di- or tri(meth)acrylic acid ester of a polyhydric alcohol ( e.g., ethylene glycol diacrylate, ethylene glycol dimethacrylate).
In addition to the styrene monomer and the polyfunctional monomer, the crosslinked styrene polymer may further contain copolymerized acrylonitrile, methyl methacrylate, maleic anhydride, etc.
In the present invention, the crosslinked styrene polymer can be used as either an aqueous dispersion or a dry powder . The dry powder is preferable for ease of handling. Various methods for drying can be used, such as hot air drying and spray drying, but spray drying is preferred.
In the present invention, the specific gravity of the crosslinked styrene polymer is 0.5 to 1.1, preferably 0.6 to 0.9. In order to reduce the specific gravity of the crosslinked styrene polymer, the crosslinked styrene polymer is preferably in the form of hollow or porous particles.
There is no particular limitation on the method for producing the crosslinked hollow particles, but they can be preferably produced by the methods described in JP-A Nos. 62-127336 and 61-185505.

[0007]
When the crosslinked styrene polymer is in the form of particles , the particle size is usually 0.1 to 10 μm.
In the present invention, preferred polymer compositions for the hollow or porous crosslinked styrene particles include methyl methacrylate/divinylbenzene/methacrylic acid, methyl methacrylate/divinylbenzene/styrene and/or α-methylstyrene/methacrylic acid, styrene and/or α-methylstyrene/divinylbenzene/methacrylic acid, etc.

[0008]
Component (c) of the present invention is a hydrogenated block copolymer comprising (A) 2 to 98% by weight of at least one block segment selected from (A-1) a styrene polymer block segment (hereinafter sometimes referred to as "block A1") and (A-2) a polybutadiene block segment having a 1,2-vinyl bond content of less than 20% (hereinafter sometimes referred to as "block A2"), and (B) 2 to 98% by weight of a butadiene (co)polymer block segment having a 1,2-vinyl bond content of 20 to 95% in the butadiene moiety and/or an isoprene (co)polymer block segment having a vinyl bond content of 10 to 95% in the isoprene moiety (hereinafter sometimes referred to as "block B"), which comprises 50 to 100% by weight of butadiene and/or isoprene and/or a copolymer having a vinyl bond content of 10 to 95% in the isoprene moiety (hereinafter sometimes referred to as "block B"), where (A) + (B) = 100% by weight , and wherein 90% or more of the unsaturated double bonds of the block copolymer have a linear or branched block structure and are hydrogenated.

[0009]
The preferred specific design principles for block A2 and block B are summarized as follows.
Case 1 (olefin polymer containing ethylene as the main monomer component);
Block A2 in component (c) becomes crystalline and polyethylene-like in structure upon hydrogenation, resulting in excellent compatibility with olefin polymers (e.g., polyethylene) containing ethylene as the primary monomer component. Therefore, compatibilizers containing block A2 are particularly preferred for component (a), which contains an olefin polymer containing ethylene as the primary monomer component. In this case, designing block B as a segment with excellent rubber-like properties is preferred, as this dramatically improves impact resistance. When block B is designed as a segment with excellent rubber-like properties, it is preferable to set the vinyl bond content of the diene portion of block B to an appropriate value within the range described in the claims. For example, the vinyl bond content of the diene portion of block B is 30 to 55% by weight, preferably 35 to 50% by weight, for butadiene, and 40% by weight or less, preferably 30% by weight or less, for isoprene. Within this vinyl bond content range, block B exhibits excellent rubber-like properties.

[0012]
Block B is composed of 50 to 100% by weight of butadiene and/or isoprene and 50 to 0% by weight of other monomers, and is a butadiene- based (co)polymer block segment having a 1,2-vinyl bond content of 20 to 95% in the butadiene portion and/or an isoprene -based (co)polymer block segment having a vinyl bond content of 10 to 95% in the isoprene portion.
As mentioned above, block B is a block segment whose role varies greatly depending on the overall structure of component (c) and the intended use.
In the present invention, the 1,2-vinyl bond content of the butadiene portion refers to the amount of butadiene having a 1,2-bond in the butadiene block, and the vinyl bond content of the isoprene portion refers to the total amount of isoprene having a 1,2-bond and isoprene having a 3,4-bond in the isoprene block.

[0019]
The thermoplastic resin composition of the present invention mainly comprises the above components (A) to (C). In addition, the composition may contain hindered phenol antioxidants such as 2,6-di-t-butyl-4-methylphenol, 2-(1-methylcyclohexyl)-4,6-dimethylphenol, 1,6 -hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] and pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], thioether antioxidants such as pentaerythritol tetrakis(3-laurylthiopropionate) and dilauryl 3,3′-thiodipropionate, phosphorus-based antioxidants such as trisnonylphenyl phosphite and distearyl pentaerythritol diphosphite, antistatic agents such as stearamidopropyldimethyl-β-hydroxyethylammonium nitrate, and 4-acetoxy-2 Weatherproofing agents such as 2,6-tetramethylpiperidine and 4-stearoyloxy-2,2,6,6-tetramethylpiperidine; ultraviolet absorbers such as p-t-butylphenyl salicylate and 2,2'-dihydroxy-4-methoxybenzophenone; lubricants such as paraffin wax, polyethylene wax, higher fatty acids or their metal salts; colorants such as titanium oxide and carbon black; fillers such as glass fiber, carbon fiber, metal fiber, aramid fiber, glass beads, asbestos, mica, calcium carbonate, potassium titanate whisker, talc, barium sulfate, glass flakes and fluororesin; or other rubber polymers, thermoplastic resins, etc. may also be appropriately blended. Furthermore, deodorizers such as 1-menthol and citrus oil may also be appropriately blended as needed.
The composition of the present invention can be obtained by melt-kneading using an extruder, kneader, Banbury mixer, or the like. To produce the composition of the present invention, the components may be mixed all at once, or any components may be premixed in advance, and the remaining components may be added and mixed. The most preferred production apparatus is a single-screw or twin-screw extruder, which allows for continuous and efficient kneading and pelletization. The resulting pellets can be extrusion-molded to form molded articles. Examples of extrusion-molded articles obtained using the composition of the present invention include sheets, films, tubes, and the like, and can be used for a variety of purposes.

[0020]
[Example]
The present invention will be explained in more detail below by way of examples, but the present invention is not limited to these examples.
In the examples, parts and percentages are by weight unless otherwise specified.
In addition, various measurements in the examples were carried out according to the following methods.
(1) Bound vinyl aromatic compound content: Measured by infrared analysis based on the absorption of phenyl groups at 679 nm ^-1 .
(2) Vinyl bond content of conjugated diene: Calculated by Hampton's method using infrared analysis.
(3) Hydrogenation rate: Calculated from 10 MHz ¹ H - NMR spectrum using ethylene tetrachloride as a solvent.
(4) Weight average molecular weight: Determined in terms of polystyrene by gel permeation chromatography (GPC) at 135°C using trichlorobenzene as a solvent.
(5) Specific gravity: Measured in accordance with JIS K-7112.
(6) Melt flow rate (MFR)
Measurement was carried out in accordance with JIS K7210 at 230°C and a load of 2.16 kg.
(7) Izod impact strength: Measured in accordance with JIS K7110.
(8) Tensile properties: Measured in accordance with JIS K7113.

[0021]
Preparation of component (b): 98 parts of styrene, 2 parts of methacrylic acid, and 10 parts of t-dodecyl mercaptan were added to an aqueous solution of 0.5 parts of sodium lauryl sulfate and 1.0 part of potassium persulfate in 200 parts of water, and polymerized with stirring at 70° C. for 8 hours to obtain polymer particles. The polymer particles had an average particle size of 0.22 μm, a toluene-insoluble content of 3%, a number-average molecular weight by GPC of 4,100, and a ratio of weight-average molecular weight to number-average molecular weight Mw/Mn of 2.4.
Next, using these polymer particles as a seed polymer, 10 parts of the polymer particles (solid content), 0.1 part of polyoxyethylene nonylphenyl ether, 0.3 part of sodium lauryl sulfate, and 0.5 part of potassium persulfate were dispersed in 900 parts of water. To this was added a mixture of 80 parts of methyl methacrylate, 10 parts of divinylbenzene (pure product equivalent), and 10 parts of styrene , and the mixture was stirred at 30° C. for 1 hour, whereupon the above substances were almost completely absorbed into the seed polymer particles.
This was polymerized at 70° C. for 5 hours, whereupon an aqueous dispersion of hollow crosslinked polymer particles (hereinafter referred to as hollow particles (b)) having a pH of 3.0 was obtained with a polymerization yield of 98%.

[0022]
(C) Production of components (production of C-1 to C-5)
2.5 kg of cyclohexane, 500 g of 1,3-butadiene, and 0.4 g of n-butyllithium were placed in an autoclave having an internal volume of 5 liters, and after the polymerization conversion rate reached 18% at 50°C, 9.8 g of tetrahydrofuran was added, the temperature was raised, and polymerization was continued until the polymerization conversion rate reached 100%.
Next, 90 g of styrene was added and the polymerization was continued.
After the polymerization was completed, the reaction mixture was heated to 70°C, and 0.8 g of n-butyllithium, 0.8 g of 2,6-di-t-butyl-p-cresol, 0.25 g of bis(cyclopentadienyl)titanium dichloride, and 1 g of diethylaluminum chloride were added. The mixture was heated under a hydrogen pressure of 10 kg/cm² ^. The reaction was carried out at rt for 1 hour. This reaction solution was mixed with a large amount of methyl alcohol, and the precipitated solid was collected and dried to obtain hydrogenated block copolymer III-1 . The hydrogenation rate of the obtained hydrogenated block copolymer III-1 was 99%, the 1,2-vinyl bond content of the first stage was 12%, and the 1,2-vinyl bond content of the second stage was 40%.
Furthermore, hydrogenated block copolymers Ha-2 to Ha-5 were obtained similarly to hydrogenated block copolymer Ha-1 by varying the monomer type, monomer amount, catalyst amount, polymerization temperature, polymerization time, etc., so as to obtain hydrogenated block copolymers as shown in Table 1.
Structure 1: Block A1 - Block B - Block A2
Structure 2: Block A1-Block B

[0023]
Examples 1 to 7
A resin mixture was prepared according to the formulation shown in Table 2 and pelletized using a twin-screw extruder PCM45 manufactured by Ikegai Iron Works Co., Ltd. The pellets were then injection molded to obtain test pieces. The results are shown in Table 2.

[0024]
Comparative Examples 1 to 7
A resin mixture was prepared according to the formulation shown in Table 3 and pelletized using a twin-screw extruder PCM45 manufactured by Ikegai Iron Works Co., Ltd. The pellets were then injection molded to obtain test pieces. The results are shown in Table 3.
The resins used in Tables 2 and 3 are shown below.
Low-density polyethylene: Petrothene 190, manufactured by Tosoh Corporation
Polypropylene: MA-2A, manufactured by Mitsubishi Petrochemical Co., Ltd.
G1650: SEBS manufactured by Shell Chemical Co., Ltd. A hydrogenated block copolymer obtained by hydrogenating a styrene-butadiene-styrene block copolymer. Its microstructure contains approximately 40% by weight of butadiene blocks having 1,2-vinyl bonds.
A1100: MODIPER A1100 (a graft copolymer in which polystyrene is grafted onto polyethylene chains), manufactured by NOF Corporation

[0026]
[Table 2]

[0027]
[Table 3]

Claims (8)

(a) olefin polymers,
(B) a crosslinked styrene-based polymer having a specific gravity of 0.5 to 1.1; and (C) (A) at least one block segment selected from (A-1) a styrene-based polymer block segment and (A-2) a polybutadiene block segment having a 1,2-vinyl bond content of less than 20%, and (B) a hydrogenated block copolymer having a linear or branched block structure, the block copolymer comprising a butadiene-based (co)polymer block segment having a 1,2-vinyl bond content of 20% or more in the butadiene portion and/or an isoprene-based (co)polymer block segment having a vinyl bond content of 10% or more in the isoprene portion, and having a linear or branched block structure, and having 90% or more of the unsaturated double bonds hydrogenated. 2. The thermoplastic resin composition according to claim 1, wherein the (a) olefin polymer is 10 to 99.4% by weight, the (b) crosslinked styrene polymer is 0.5 to 70% by weight, and the (c) hydrogenated block copolymer is 0.1 to 20% by weight (wherein (a) + (b) + (c) = 100% by weight). 3. The thermoplastic resin composition according to claim 1, wherein the crosslinked styrene polymer (b) is a (co)polymer containing a styrene monomer and a polyfunctional monomer as main components. 4. The thermoplastic resin composition according to claim 3, wherein said styrene-based monomer is styrene. 5. The thermoplastic resin composition according to claim 3, wherein the polyfunctional monomer is divinylbenzene or a di- or tri(meth)acrylic acid ester of a polyhydric alcohol. 6. The thermoplastic resin composition according to claim 1, wherein the crosslinked styrene polymer (b) is in the form of hollow or porous particles. 7. The thermoplastic resin composition according to claim 6, wherein the hollow or porous particles have a particle diameter of 0.1 to 10 [mu]m. 8. The thermoplastic resin composition according to claim 1, wherein the hydrogenated block copolymer (c) comprises 2 to 98% by weight of the (A) block segment and 2 to 98% by weight of the (B) block segment (where (A) + (B) = 100% by weight), wherein the (B) block segment contains 50 to 100% by weight of butadiene and/or isoprene and 50 to 0% by weight of other monomers, and comprises a butadiene-based (co)polymer block segment having a 1,2-vinyl bond content of 20 to 95% in the butadiene portion and/or an isoprene-based (co)polymer block segment having a vinyl bond content of 10 to 95% in the isoprene portion.