JP3410549B2 - Thermoplastic resin composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin having good injection moldability, and a molded article having excellent rigidity and low-temperature impact resistance. The present invention relates to a resin composition, and provides a thermoplastic resin composition molded into a molded article having excellent properties as interior and exterior parts of automobiles, various industrial parts, and the like. [0002] A thermoplastic resin composition comprising a mixed composition of a polypropylene resin and an ethylene / propylene rubber is formed into a molded article having excellent mechanical strength and impact resistance, and is economically advantageous. Because of its excellent recyclability, it is used as a raw material for obtaining molded articles in a wide range of fields including interior and exterior parts of automobiles. [0003] However, the conventional thermoplastic resin composition of a polypropylene resin and an ethylene / propylene rubber has an injection moldability and a room temperature of a molded article of the thermoplastic resin composition. The balance between rigidity at low temperatures and impact resistance at low temperatures is not yet sufficient. [0004] On the other hand, the present invention provides a thermoplastic resin composition which is excellent in injection moldability and is molded into a molded article having good balance between rigidity at normal temperature and impact resistance at low temperature. The purpose is to do. [0005] According to the present invention, the above-mentioned object is to provide a polypropylene-based resin (1)... 100 parts by weight. Hydrogenated block copolymer (2) having a number average molecular weight of 500,000 or less 5 to 100 parts by weight Block A: number average molecular weight of 2,500 to 200,000
And a hydrogenated block block B of a butadiene polymer having a vinyl bond amount of 20% or less: a number average molecular weight of 30,000 to 300,000
In a vinyl bond content of 20% or less isoprene / butadiene = 30 / 70-100 / 0 consisting (by weight) polymer hydrogenated block ethylene Pro Pi Ren-based rubber (3) ·······・ 0-100
Parts by weight, and at a temperature of 200 ° C. and a shear rate of 1220 (1/1).
Melt viscosity of hydrogenated block copolymer (2)
The melt viscosity of the polypropylene resin (1) is 0.5 to 1
This can be achieved by providing a thermoplastic resin composition in the range of 0.0. Hereinafter, the thermoplastic resin composition of the present invention will be described in more detail. There is no particular limitation on the polypropylene resin which is the component (1) used in the thermoplastic resin composition of the present invention. When importance is placed on the properties, block polypropylene is preferably used, and when importance is placed on transparency, random polypropylene is preferably used. These polypropylene resins may be used in combination. As a polypropylene resin, 230 ° C.
2. If the MFR under a load of 16 kg is less than 5 g / 10 min, the moldability of the composition is reduced.
FR of 5 g / 10 min or more, more preferably 10 g / 1
A polypropylene-based resin of 0 minutes or more is preferable. [0009] As these polypropylene resins, permissible not be used modified polypropylene, hydroxyl groups at the molecular terminal, carboxyl group, a polypropylene pin Ren or the like by introducing a functional group such as epoxy group by a carboxylic acid derivative or its anhydride . The block A in the hydrogenated block copolymer which is the component (2) used in the thermoplastic resin composition of the present invention is a butadiene polymer having a number average molecular weight of 2,500 to 200,000 and a vinyl bond amount of 20% or less. It is a hydrogenation block. When the vinyl bond content of the butadiene polymer in the hydrogenated block exceeds 20%, a molded product having sufficient rigidity cannot be obtained. The number average molecular weight of the polymer used in the present invention is the molecular weight in terms of polystyrene determined by the GPC method. If the number average molecular weight of the hydrogenated block of the butadiene polymer is less than 2500, a molded article having a sufficient rigidity cannot be obtained, and if it exceeds 200,000, the hydrogenated block copolymer (2) cannot be obtained. Since the melt viscosity becomes high, the moldability of the composition becomes poor. If the hydrogenation rate of the hydrogenated block of the butadiene polymer is less than 85%, a molded article having excellent rigidity and heat aging resistance cannot be obtained. Above hydrogenation rate, more preferably 9
The hydrogenation rate is preferably 0% or more. The proportion of the block A in the hydrogenated block copolymer (2) is preferably 5 to 70% by weight, more preferably 20 to 50% by weight. When the proportion of the block A in the hydrogenated block copolymer (2) is less than 5% by weight, the rigidity of a molded article obtained from the composition tends to decrease. The impact resistance of the resulting molded article at low temperatures tends to be insufficient. Component (2) of the thermoplastic resin composition of the present invention
The block B in the hydrogenated block copolymer having a weight ratio of isoprene / butadiene of 30/70 to 100 /
It is a hydrogenated block of a polymer consisting of 0. The vinyl bond amount in the block B is 20%
If it exceeds 50, the molded article obtained from the composition will have insufficient impact resistance at low temperatures, so that the vinyl bond amount of the block B needs to be 20% or less. When the number average molecular weight of the block B is less than 30,000, the molded article obtained from the composition has insufficient impact resistance at low temperatures, and when it exceeds 300,000, the hydrogenated block copolymer (2) has The melt viscosity increases, and the moldability of the composition deteriorates. For this reason, the block B in the hydrogenated block copolymer (2) needs to have a number average molecular weight of 30,000 to 300,000. Further, the content of isoprene in the block B is less than 30 wt%, the impact resistance at low temperatures by I resulting <br/> Ru molded body composition becomes insufficient, block The content of isoprene in B must be at least 30% by weight. When the block B is composed of an isoprene polymer and a butadiene polymer, the polymerization mode of the isoprene polymer and the butadiene polymer may be any of random, block and tapered, but is preferably random. is there. The block structure of the hydrogenated block copolymer (2) is A- (BA) _m or (AB) _n (provided that
m and n are integers of 1 or more), and may be any of linear or branched, and preferably ABA
Type or AB type. If the number average molecular weight of the hydrogenated block copolymer (2) exceeds 500,000, the moldability of the composition becomes poor.
It is necessary to have a number average molecular weight of 00 or less, and particularly preferably a number average molecular weight of 300,000 or less. The hydrogenated block copolymer (2) can be used to the extent that the object of the present invention is not impaired.
May have a functional group such as a carboxyl group, an acid anhydride group, a hydroxyl group, an epoxy group, or an amino group at the molecular terminal or in the molecular chain. When the addition amount of the hydrogenated block copolymer (2) is less than 5 parts by weight based on 100 parts by weight of the polypropylene resin (1), the modification effect by the addition of the hydrogenated block copolymer (2) is obtained. If not more than 100 parts by weight, the rigidity of the molded article obtained from the composition is reduced.
For this reason, the hydrogenated block copolymer (2) is added at a ratio of 5 to 100 parts by weight based on 100 parts by weight of the polypropylene resin (1). The method for producing the block copolymer before hydrogenation of the hydrogenated block copolymer which is the component (2) includes, for example, a method in which an alkyllithium compound is used as an initiator and a monomer is sequentially added to carry out polymerization. A method of obtaining a polymer by coupling with a coupling agent or the like can be used. Examples of the alkyl lithium compound as the initiator include alkyl compounds having 1 to 10 carbon atoms in the alkyl residue, and particularly preferred are methyl lithium, ethyl lithium, pentyl lithium, butyl lithium and the like. As the coupling agent, dichloromethane, dibromomethane, dichloroethane, dibromoethane, dibromobenzene, phenyl benzoate and the like are used. The amount of the initiator used is determined by the molecular weight of the target block copolymer, but is used in the range of 0.01 to 0.2 parts by weight based on 100 parts by weight of all monomers used for polymerization. Is good. As the reaction solvent, an organic solvent inert to the polymerization initiator is used. Particularly, aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons having 6 to 12 carbon atoms are preferable, and examples thereof include hexane, heptane, cyclohexane, methylcyclohexane, and benzene. The polymerization reaction is in each case from 0 to 80
C., for about 0.5 to 50 hours. The hydrogenation reaction of the obtained block copolymer is as follows:
It is preferable to carry out the reaction by a known method of reacting hydrogen in a molecular state with the hydrogenation catalyst and the block copolymer dissolved in a solvent inert to the reaction. As the catalyst for the hydrogenation reaction, a heterogeneous catalyst comprising Raney nickel, or a metal such as Pt, Pd, Ru, Rh, Ni or the like supported on a carrier such as carbon, alumina or diatomaceous earth, or A Ziegler-based catalyst composed of a combination of a transition metal, an alkylaluminum compound, an alkyllithium compound and the like is used. The hydrogenation reaction is carried out at normal pressure to 200 kg / cm
The reaction is carried out at a hydrogen pressure of ² , a reaction temperature of room temperature to 250 ° C., and a reaction time of 1 to 100 hours. The block copolymer after the hydrogenation reaction is heated or dried under reduced pressure after coagulating the reaction solution with methanol or the like, or the reaction solution is poured into boiling water to remove the solvent by azeotropic distillation, and then heated. Alternatively, it is obtained by drying under reduced pressure. The polypropylene resin (1) and the hydrogenated block copolymer (2) were mixed at a temperature of 200 ° C. and a shear rate of 1220.
(1/2) “melt viscosity of hydrogenated block copolymer (2) / melt viscosity of polypropylene resin (1)”
It is necessary to be in the range of 0.5 to 10.0, preferably 1.0 to 8.0. When “melt viscosity of hydrogenated block copolymer (2) / melt viscosity of polypropylene resin (1)” at 200 ° C. and a shear rate of 1220 (1 / sec) is less than 0.5, In addition, slipping easily occurs in the melting and kneading steps of the composition, it is difficult to perform sufficient kneading, and a uniform composition cannot be obtained. In addition, 200 ° C., shear rate 1220
(1) melt viscosity of hydrogenated block copolymer (2) / melt viscosity of polypropylene resin (1)
If it exceeds 0, the dispersibility of the hydrogenated block copolymer (2) becomes poor, and a uniform composition cannot be obtained. The ethylene / propylene rubber of the component (3) is mixed in a range of 100 parts by weight or less based on 100 parts by weight of the polypropylene resin (1). If the ethylene / propylene rubber (3) exceeds 100 parts by weight with respect to 100 parts by weight of the polypropylene resin (1), the rigidity of a molded article obtained from the composition becomes inferior. As the ethylene / propylene rubber, a rubbery copolymer composed of a two-component system of ethylene / propylene or a three-component system of ethylene / propylene / non-conjugated diene is used. The ethylene / propylene rubber preferably has a propylene content in the range of 10 to 60% by weight.
In particular, those having a propylene content of 20 to 40% by weight are preferred. Further, the thermoplastic resin composition of the present invention may contain various additives such as carbon black, silica, calcium carbonate, talc, mica, magnesium hydroxide, clay, barium sulfate, and the like, as long as their properties are not impaired. Fillers such as natural silicic acid, titanium oxide, basic magnesium sulfate, etc., glass fibers, surface-treated glass fibers, carbon fibers, fibrous fillers such as ceramic fibers, antioxidants, ultraviolet absorbers, coloring agents, crosslinking agents, foaming Agents, flame retardants,
A nucleating agent, an antistatic agent, a coating improver and the like can be contained as required. Further, the thermoplastic resin composition of the present invention may contain other thermoplastic resins, such as a styrene-butadiene block copolymer and a hydrogenated product thereof, and a styrene-isoprene block copolymer, as long as the properties are not impaired. It is possible to mix thermoplastic resins such as coalesce and hydrogenated products thereof, polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer and ethylene-methyl methacrylate copolymer. The mixing ratio of these thermoplastic resins is preferably about 50% by weight or less based on the thermoplastic resin composition of the present invention. The thermoplastic resin composition of the present invention can be produced by using a usual kneader such as a kneader, a Banbury mixer, a roll, a Brabender plastograph, a single screw extruder, a twin screw extruder or the like. The method for molding a molded article using the thermoplastic resin composition of the present invention is not particularly limited, and includes press molding, injection molding, extrusion molding, hollow molding, sheet molding, film molding, lamination molding, rotational molding, and the like. Can be used, but a molding method by injection molding is particularly desirable. A molded article made of the thermoplastic resin composition of the present invention is usually obtained by kneading with an extruder or the like to obtain pellets and then molding using the pellets as a raw material. Alternatively, each component can be directly supplied to a molding machine and molded while kneading with the molding machine. The thermoplastic resin composition of the present invention is excellent in moldability, moreover, rigidity, impact resistance at low temperature, economical efficiency, the advantage that the molded body is obtained having excellent Lisa <br/> acme Le resistance For example, automotive exterior parts such as bumpers, side moldings, tire houses, etc., automotive interior parts such as dashboards, various parts of electronic and home appliances, housing materials, medical materials, sports equipment, various packaging And various packaging films. EXAMPLES Hereinafter, the specific constitution of the thermoplastic resin composition of the present invention will be described based on examples. REFERENCE EXAMPLE 1 (Production of block copolymer) In a pressure-resistant reactor replaced with dry nitrogen, cyclohexane was used as a solvent, n-butyllithium was used as a polymerization catalyst, and isoprene was polymerized after polymerizing butadiene. Polymerized, AB type block copolymer (I), (II), (III),
(V), (VI), (VII) and (IX) were obtained. Reference Example 2 (Production of block copolymer) In a pressure-resistant reactor substituted with dry nitrogen, cyclohexane was used as a solvent, n-butyllithium was used as a polymerization catalyst, and butadiene was polymerized. Content 50 wt. % Of a mixed monomer of butadiene and isoprene was polymerized, and then butadiene was polymerized to obtain an ABA block copolymer (IV). Reference Example 3 (Preparation of Block Copolymer) In a pressure-resistant reactor purged with dry nitrogen, cyclohexane was used as a solvent, n-butyllithium was used as a polymerization catalyst, and tetrahydrofuran was used as a vinylating agent. , Butadiene is polymerized and then isoprene is polymerized.
A B-type block copolymer (VIII) was obtained. Reference Example 4 (Production of hydrogenated block copolymer) Block copolymers obtained in Reference Examples 1 to 3
Each of (I) to (IX) was subjected to a hydrogenation reaction in cyclohexane using Pd-C as a hydrogenation catalyst at a hydrogen pressure of 20 kg / cm ² to correspond to the block copolymers (I) to (IX). The respective hydrogenated block copolymers (i) to (ix) were obtained. The molecular properties of the block copolymers (I) to (IX) and the hydrogenated block copolymers (i) to (ix) are shown in Tables 1 and 2. In Tables 1 and 2, the number average molecular weight is the molecular weight in terms of polystyrene by GPC before hydrogenation, the hydrogenation ratio is measured by NMR, and the melt viscosity is 200. It is a measurement result at ° C and a shear rate of 1220 (1 / second). [Table 1] [Table 2] In the examples and comparative examples described below, the following polypropylene resin and ethylene
Propylene rubber was used. [0056] [(manufactured by Mitsubishi Petrochemical (Ltd.)) BC-1] a polypropylene resin PP-1 ···· M FR = 30 blocks polypropylene (g / 10 min): 20
Melt viscosity at 0 ° C., shear rate 1220 (1 / second); 78
0 poise PP-2 ···· M FR = 200 (g / 10 min) Homo polypropylene [MR002V (Mitsubishi Petrochemical Ltd. Co.): 2
Melt viscosity at 00 ° C. and a shear rate of 1220 (1 / second); 3
90 poise PP-3 ···· M FR = homopolypropylene of 25 (g / 10 min) [MA-2A (manufactured by Mitsubishi Petrochemical Co., Ltd.): 200
850 ° C., melt viscosity at a shear rate of 1220 (1 / second); 850
Poise [0057] ethylene-propylene rubber EPR ···· M FR = 1.6 (g / 10 min) propylene content 22 wt. % Of ethylene / propylene rubber [Esprene V0111 (manufactured by Sumitomo Chemical Co., Ltd.)] Example 1 100 parts by weight of polypropylene (PP-1) and Reference Example 4
40 parts by weight of the hydrogenated block copolymer (i) obtained in the above was used at a temperature of 200 ° C. and a rotation speed of 100 rpm using a twin-screw extruder.
To obtain pellets. Next, the obtained pellets were molded at a molding temperature of 23.
A test piece was prepared by injection molding at 0 ° C., and the physical properties were evaluated.
The results are shown in [Table 5]. Examples 2 to 6 100 parts by weight of polypropylene (PP-1) and Reference Example 4
40 parts by weight of the hydrogenated block copolymers (ii) to (vi) obtained in the above were kneaded in the same manner as in Example 1 to obtain pellets. Next, the obtained pellets were injection molded in the same manner as in Example 1 to prepare test pieces, and the physical properties were evaluated. The results are shown in [Table 5]. Example 7 100 parts by weight of polypropylene (PP-1), 30 parts by weight of a hydrogenated block copolymer (i), and 10 parts by weight of ethylene / propylene rubber (EPR) were prepared in the same manner as in Example 1. The mixture was kneaded to obtain pellets. Next, the obtained pellets were injection molded in the same manner as in Example 1 to prepare test pieces, and the physical properties were evaluated. The results are shown in [Table 5]. Example 8 100 parts by weight of polypropylene (PP-3) and 70 parts by weight of a hydrogenated block copolymer (ii) were kneaded in the same manner as in Example 1 to obtain pellets. Next, the obtained pellets were injection-molded in the same manner as in Example 1 to prepare test pieces, and the physical properties were evaluated. The results are shown in [Table 5]. Comparative Example 1 Kneading was attempted in the same manner as in Example 1 by using 100 parts by weight of polypropylene (PP-1) and 40 parts by weight of the hydrogenated block copolymer (vii) obtained in Reference Example 4. No stable strand was obtained. Comparative Example 2 100 parts by weight of polypropylene (PP-2) and 40 parts by weight of a hydrogenated block copolymer (v) were kneaded in the same manner as in Example 1 to obtain pellets. Next, the obtained pellets were injection-molded in the same manner as in Example 1 to prepare test pieces, and the physical properties were evaluated. As a result, the fluctuation width of the physical properties was large, and a molded article having uniform physical properties could not be obtained. . Comparative Example 3 100 parts by weight of polypropylene (PP-1) and 40 parts by weight of a hydrogenated block copolymer (viii) were kneaded in the same manner as in Example 1 to obtain pellets. Next, the obtained pellets were injection-molded in the same manner as in Example 1 to prepare test pieces, and the physical properties were evaluated. The results are shown in [Table 5]. This test piece was inferior in rigidity to the test piece using the composition of the example. Comparative Example 4 100 parts by weight of polypropylene (PP-1) and 40 parts by weight of ethylene / propylene rubber (EPR) were used in Example 1
To obtain pellets. Next, the obtained pellets were injection molded in the same manner as in Example 1 to prepare test pieces, and the physical properties were evaluated. The results are shown in [Table 5]. This test piece was inferior in impact resistance at low temperature as compared with the test piece using the composition of the example. Comparative Example 5 100 parts by weight of polypropylene (PP-3) and 70 parts by weight of ethylene / propylene rubber (EPR) were used in Example 1
To obtain pellets. Next, the obtained pellets were injection-molded in the same manner as in Example 1 to prepare test pieces, and the physical properties were evaluated. The results are shown in [Table 5]. This test piece was inferior in impact resistance at low temperature as compared with the test piece using the composition of the example. In the above Examples and Comparative Examples, the weight ratio of the component compositions of the compositions was 200 ° C., and the shear rate was 1220 (1/1).
The melt viscosity of the hydrogenated block copolymer / melt viscosity of the polypropylene-based resin, ie, the melt viscosity ratio, and the moldability are shown in [Table 3] and [Table 4]. The moldability of the compositions of Examples and Comparative Examples and the physical properties of the molded articles of the compositions were evaluated by the following methods. (Formability) Temperature 230 ° C., Load 2.16K
g was evaluated by MFR (g / 10 minutes). (Impact resistance at low temperature)
Impact strength (kg ·
cm / cm). (Rigidity) Flexural modulus at 25 ° C. (kg
/ Cm ² ). [Table 3] (*) ··· “Melt viscosity of hydrogenated block copolymer / melt viscosity of polypropylene resin” at 200 ° C and a shear rate of 1220 (1 / sec) (**) ··· Temperature 230 ° C, load 2.16 kg of MFR
(G / 10 minutes) (*) ··· “Melt viscosity of hydrogenated block copolymer / melt viscosity of polypropylene resin” at 200 ° C and a shear rate of 1220 (1 / sec) (**) ··· Temperature 230 ° C, load 2.16 kg of MFR
(G / 10 minutes) Comparative Example 6 100 parts by weight of polypropylene (PP-1) and Reference Example 4
40 parts by weight of the hydrogenated block copolymer (ix) obtained in the above was kneaded with a Brabender plastograph at a temperature of 200 ° C. and a rotation speed of 100 rpm for 5 minutes to obtain a softened composition. A test piece was prepared by press-molding this composition, and the impact strength measured by a notched Izod impact test was 8 kg · cm / cm. Was inferior. [0085] [Effect of the Invention The thermoplastic resin composition of the present invention is obtained by adding a hydrogenated block copolymer of a specific polypropylene resin, exhibit the excellent effect in moldability and rigidity and to become a molded article having excellent properties in balance between impact resistance at low temperatures, a molded article of interior trim and exterior Hinto automobile This First, the effect on practical use as various molded articles for the raw material of a large is there.

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hirayama ▲ Yoshio Kuraray 36, Kamisu-cho, Kashima-gun, Ibaraki Pref. Kuraray Co., Ltd. (56) References JP-A-1-168743 (JP, A) JP-A-2 -245009 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 1/00-101/16

Claims (1)

(57) [Claims] [Claim 1] Polypropylene resin (1) ... 1
00 parts by weight Hydrogenated block copolymer (2) having at least one of the following blocks A and B and having a number average molecular weight of 500,000 or less 5 to 100 parts by weight A: Number average molecular weight is 2,500 to 200,000
And a hydrogenated block block B of a butadiene polymer having a vinyl bond amount of 20% or less: a number average molecular weight of 30,000 to 300,000
In a vinyl bond content of 20% or less isoprene / butadiene = 30 / 70-100 / 0 consisting (by weight) polymer hydrogenated block ethylene Pro Pi Ren-based rubber (3) ·······・ 0-100
The melt viscosity of the hydrogenated block copolymer (2) / the melt viscosity of the polypropylene resin (1) at 200 ° C. and a shear rate of 1220 (1 / second) is 0.5 to 10.0. The thermoplastic resin composition characterized by being in the range of.