JPH0692522B2 - Block copolymer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a block copolymer composition comprising a conjugated diene and a vinyl aromatic hydrocarbon which are excellent in transparency, color tone, blocking resistance and impact resistance. Regarding

[Conventional technology]

A block copolymer composed of a conjugated diene and a vinyl aromatic hydrocarbon has excellent transparency when the content of the vinyl aromatic hydrocarbon is relatively high, and a thermoplastic resin having a better impact resistance than polystyrene can be obtained. In recent years, its usage has been increasing mainly in fields such as food packaging containers, daily sundries, toys, and light electric parts.

Such block copolymers are used in various applications such as sheets, extrusion-molded products such as films, and molded products obtained by thermoforming them by methods such as vacuum molding and pressure molding, injection-molded products and the like. The block copolymer is generally used because it has high adhesiveness, and the mold release resistance with the mold and the mold release resistance between the molded products are large, so that a molded product with a good appearance cannot be obtained. However, there is a problem in that it requires special measures or it becomes difficult to separate molded products from each other during use.

In order to improve such problems, (1) inorganic fine particles (eg calcium carbonate, silica), (2) fatty acid, (3)
It is generally known to add fatty acid amides, (4) fatty acid esters, (5) other resins. For example,
49-66744 discloses a method of adding a hardened animal or vegetable oil, and JP-A-50-80350 and JP-A-50-155555 disclose glycerin fatty acid ester and / or carbon number 12
~ 22 fatty acid, JP-A-52-130852 discloses a method of adding porous silica gel, JP-A-54-3024
No. 6 discloses a method of using montanic acid wax and a fatty acid amide in combination.

[Problems to be Solved by the Invention]

However, even in the methods disclosed in these methods, there are problems that the block resistance is insufficient and the transparency and the color tone are inferior, and improvement thereof is desired.

[Means for Solving the Problems]

The present inventors have found that by adding a microcrystalline wax having a melting point in a specific range to a block copolymer in which the ratio of the block-shaped homopolymer segment present in the block copolymer is in a specific range. The inventors have found that the above problems can be solved and completed the present invention.

That is, the present invention provides a block copolymer comprising a conjugated diene and a vinyl aromatic hydrocarbon and having a vinyl aromatic hydrocarbon content of 60 to 95% by weight, and The block copolymer composition comprises 100 parts by weight of the block copolymer and 0.01 to 3 parts by weight of microcrystalline wax having a melting point of 70 to 120 ° C.

The present invention will be described in detail below.

The block copolymer used in the present invention comprises at least 1
, Preferably two or more polymer segments mainly composed of vinyl aromatic hydrocarbons and at least one polymer segment mainly composed of conjugated dienes, and having a vinyl aromatic hydrocarbon content of 60 to 95. % By weight, preferably 65-90% by weight,
More preferably, it is 70 to 85% by weight. If the content of the vinyl aromatic hydrocarbon is less than 60% by weight, the rigidity is inferior, and if it exceeds 95% by weight, the impact resistance is inferior, which is not preferable. The block copolymer used in the present invention has a proportion of vinyl aromatic hydrocarbons present as a block-like homopolymer segment in the block copolymer of 50 to 98% by weight, preferably 60 to 96. % By weight, more preferably 70-94
% By weight. When the proportion of vinyl aromatic hydrocarbons present as a block-like homopolymer segment is less than 50% by weight, the rigidity is poor, and when it exceeds 98% by weight, not only the impact resistance is poor but also the microcrystalline It is not preferable because the wax easily bleeds. The vinyl aromatic hydrocarbon present as a block-like homopolymer segment in the block copolymer is a method of oxidatively decomposing the copolymer with diethyl butyl hydroperoxide using osmium tetroxide as a catalyst (for example, L.M.・
Kolthoff et l, J, Polymer Sci., 1, 429 (1946))) and the like. Therefore, the ratio of vinyl aromatic hydrocarbons present as block-like homopolymer segments in the block copolymer, the amount of the block-like homopolymer segment quantified by such a method, in the block copolymer It can be understood by dividing by the amount of all vinyl aromatic hydrocarbons contained in.

The block copolymer used in the present invention is represented by the general formula (AB) n, AB-A) n, BA-B) n (in the above formula, A is a polymer segment mainly containing a vinyl aromatic hydrocarbon). And B is a polymer segment mainly composed of a conjugated diene, and the boundary between the A segment and the B segment does not necessarily need to be clearly distinguished.
Is an integer of 1 or more. ) Or general formula, [(B-A _{n m + 1} X, [(A-B _{n
m + 1} X, [(B-A _n B _{m + 1} X, [(A-B _n A
_{m + 1} X, (In the above formula, A and B are the same as above, and X is, for example, coupling of silicon tetrachloride, tin tetrachloride, epoxidized soybean oil, polyhalogenated hydrocarbon, carboxylic acid ester, polyvinyl compound, etc. Represents a residue of an agent or a residue of an initiator such as a polyfunctional organolithium compound, where m and n are integers of 1 or more.). In the above formula, the polymer segment mainly composed of vinyl aromatic hydrocarbon means a copolymer block of vinyl aromatic hydrocarbon and conjugated diene containing 50% by weight or more of vinyl aromatic hydrocarbon and / or vinyl. Aromatic hydrocarbon homopolymer block refers to a polymer block mainly containing a conjugated diene. A copolymer block of a conjugated diene containing 50% by weight or more of a conjugated diene and a vinyl aromatic hydrocarbon block and / or a conjugated diene. A homopolymer block is shown.

The vinyl aromatic hydrocarbon in the copolymer block may be distributed uniformly or in a taper shape. A plurality of uniformly distributed portions and / or tapered distributed portions may coexist in each block.

A particularly preferred block copolymer in the present invention is a polymer in which the unterminated ends of the polymer molecular chains are each composed of a polymer segment mainly containing vinyl aromatic hydrocarbon, and the polymer mainly containing vinyl aromatic hydrocarbon. At least one of the segments is a vinyl aromatic hydrocarbon homopolymer block and a vinyl aromatic hydrocarbon block having a vinyl aromatic hydrocarbon content of 75 to 98% by weight, preferably 80 to 95% by weight, adjacent to the polymer block. It is a block copolymer which is a segment containing a copolymer block of hydrogen and a conjugated diene. Such a block copolymer is characterized in that it is unlikely to cause microcracks when the molded product is bent or deformed.

The block copolymer used in the present invention may be any mixture of the block copolymers represented by the above general formula.

The conjugated diene used in the present invention is a diolefin having a pair of conjugated double bonds, such as 1,3-butadiene,
2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-
Hexadiene, etc.
Examples include 3-butadiene and isoprene. These are 1
Not only the seeds but also two or more kinds may be mixed and used.

Examples of the vinyl aromatic hydrocarbon used in the present invention include styrene, o-methylstyrene, p-methylstyrene and p-te.
There are rt-butyl styrene, 1,3-dimethyl styrene, α-methyl styrene, vinyl naphthalene, vinyl anthracene and the like, but styrene is particularly common. These may be used alone or in combination of two or more.

The number average molecular weight of the block copolymer used in the present invention is 10,0.
00 to 1,000,000, preferably 20,000 to 800,000, more preferably 50,000 to 500,000.

In the present invention, a modified block copolymer in which a polar group-containing compound is reacted with the active terminal of the polymer and a polar group-containing atomic group is bonded to the polymer chain can also be used. Here, the polar group-containing atomic group means an atomic group containing at least one atom selected from nitrogen, oxygen, silicon, phosphorus, sulfur and tin. Specifically, a carboxyl group, a carbonyl group, a thiocarbonyl group, an acid halide group, an acid anhydride group, a carboxylic acid group, a thiocarboxylic acid group, an aldehyde group,
Thioaldehyde group, carboxylic acid ester group, amide group,
Sulfonic acid group, sulfonic acid ester group, phosphoric acid group, phosphoric acid ester group, amino group, imino group, nitrile group, pyridyl group, quinoline group, epoxy group, thioepoxy group, sulfide group, isocyanate group, isothiocyanate group, An atomic group containing at least one polar group selected from a silicon halide group, an alkoxysilicon group, a tin halide group, an alkyltin group, a phenyltin group and the like can be mentioned. More specifically, the terminal modification treatment agent described in Japanese Patent Application No. 61-129179 can be used, and the terminal modification treatment agent described in the specification is within the scope of the present invention. The terminal modification treatment agent for imparting the polar group-containing atomic group is 0.1 to 10 moles per 1 atomic equivalent of lithium metal at the polymer terminal,
It is preferably used in an amount of 0.2 to 5 mol, more preferably 0.5 to 2 mol.

Further, in the present invention, the block copolymer or the modified block copolymer obtained above can be partially or selectively hydrogenated by a hydrogenation reaction (hydrogenation reaction). The hydrogenation rate can be arbitrarily selected, and in order to improve the heat deterioration resistance while maintaining the properties of the unhydrogenated polymer, the aliphatic double bond based on the conjugated diene is 3% or more, 80% or more.
%, Preferably 5% or more but less than 75% Hydrogenated, or 80% to improve heat deterioration resistance and weather resistance
It is recommended to hydrogenate the above, preferably 90% or more.
In this case, the water of the aromatic double bond based on the vinyl aromatic compound copolymerized with the polymer block A mainly containing the vinyl aromatic compound and the polymer block B mainly containing the conjugated diene compound as the case requires. The addition rate is not particularly limited, but the hydrogen addition rate is preferably 20% or less. The amount of unhydrogenated aliphatic double bonds contained in the hydrogenated block copolymer can be easily known by an infrared spectrometer, a nuclear magnetic resonance apparatus or the like. As the catalyst used in the hydrogenation reaction, (1) a supported heterogeneous catalyst in which a metal such as Ni, Pt, Pb, Ru is supported on carbon, silica, alumina, diatomaceous earth, and (2) Ni Known are homogeneous catalysts such as so-called Ziegler-type catalysts using organic acid salts such as Co, Fe, Cr or acetylacetone salts and reducing agents such as organic Al, or so-called organic complex catalysts such as organic metal compounds such as Ru and Rh. Has been. Specific methods include Japanese Patent Publication No. 42-8704, Japanese Patent Publication No. 43-6636, or Japanese Patent Publication No. 59-133203, Japanese Patent Publication No. 60-2201.
According to the method described in Japanese Patent Publication No. 47, hydrogenation can be carried out in the presence of a hydrogenation catalyst in an inert solvent to obtain a hydrogenated product, and the hydrogenated block copolymer used in the present invention can be synthesized. At that time, the hydrogenation rate of the aliphatic double bond based on the conjugated diene compound in the block copolymer can be controlled to an arbitrary value by adjusting the reaction temperature, the reaction time, the hydrogen supply amount, the catalyst amount and the like.

Next, the microcrystalline wax used in the present invention has a melting point of 70 to 120 ° C, preferably 75 to 110 ° C, more preferably 80 to 100 ° C. If the melting point is less than 70 ° C, blocking resistance is poor, and if the melting point exceeds 120 ° C, transparency is deteriorated, which is not preferable. In the present invention, the melting point is ASTM
It is a value obtained by D-127. The microcrystalline wax of the present invention is generally a complex mixture containing a small amount of an aromatic compound and having branched paraffins and cycloparaffins as main components. Particularly preferred microcrystalline waxes have a penetration of 1 to 1 as measured by ASTM D-1321.
20, preferably 5 to 15, and has a feature that it is difficult to bleed.

The amount of microcrystalline wax added is 0.01 to 3 parts by weight, preferably 0.0 to 100 parts by weight of the block copolymer.
It is 5 to 2 parts by weight, more preferably 0.1 to 1 part by weight. If the addition amount is less than 0.01 parts by weight, the blocking resistance is poor, and if it exceeds 3 parts by weight, the wax bleeds and the transparency is poor, which is not preferable.

In the present invention, other lubricants can be used in combination for the purpose of further improving the blocking resistance. Other lubricants include higher fatty acids having 8 to 22 carbon atoms, higher fatty acid metal salts having 4 to 22 carbon atoms, fatty acid esters of straight chain aliphatic monohydric alcohols having 8 to 18 carbon atoms, monohydric and polyhydric alcohols, Water-operated
Examples include higher fatty acid amides such as vegetable oil, ethylenebis fatty acid amide, higher fatty acid amide, stearyl erucamide, and oleyl palmitoamide. These lubricants are generally used per 100 parts by weight of the block copolymer.
It is 0.01 to 3 parts by weight, preferably 0.05 to 2 parts by weight.

The block copolymer composition of the present invention contains various additives such as stabilizers, antistatic agents, ultraviolet absorbers, softeners, plasticizers, inorganic fillers, organic fillers and inorganic reinforcing agents according to the purpose. , An organic reinforcing agent, a tackifier, a flame retardant, a coloring agent and the like can be added.

Specifically, compounds described in "Plastics and Rubber Additives Handbook" (Chemical Industry Co., Ltd.) and the like can be used.

The block copolymer resin of the present invention can also be used in combination with other polymers. As such a polymer, a polymer of the vinyl aromatic hydrocarbon-based monomer, the vinyl aromatic hydrocarbon-based monomer and another vinyl monomer, for example, ethylene, propylene, butylene, vinyl chloride, vinylidene chloride, vinyl acetate, Acrylic ester such as methyl acrylate, methacrylic acid ester such as methyl methacrylate, copolymer with acrylonitrile, rubber modified impact resistant styrene resin (HIPS), acrylonitrile-
Butadiene-styrene copolymer (ABS), methyl methacrylate-butadiene-styrene copolymer, polyphenylene ether resin, polyethylene, polypropylene, polycarbonate, polysulfone, polyamide, polyester, polyvinyl chloride, polymethacrylic acid ester, etc. . Particularly suitable thermoplastic resins include polystyrene, polyparamethylstyrene, styrene-α-methylstyrene copolymer, styrene-methylmethacrylate copolymer, and HIPS.

The method for obtaining the block copolymer composition of the present invention can be produced by any conventionally known compounding method.
For example, an open roll, an intensive mixer, an internal mixer, a co-kneader, a continuous kneader with a twin-screw rotor, a melt-kneading method using a general kneader such as an extruder, each component is dissolved in or dispersed in a solvent And the like are used.

〔The invention's effect〕

The block copolymer composition of the present invention can be used as a molding material for various molded products by taking advantage of its excellent transparency, color tone, blocking resistance and impact resistance. That is, the block copolymer composition of the present invention is, as it is or after being colored, by a processing means similar to that of a usual thermoplastic resin, extruded products such as sheets and films, and vacuum molding and pressure molding thereof. Molded articles thermoformed by the method of, specifically food container packaging, blister packaging materials, fruits and vegetables,
It can be used in a wide range of container packaging materials such as packaging films for confectionery. In addition, it can be used for applications in which ordinary general-purpose thermoplastic resins are used, such as in the fields of toys, daily necessities, food packaging containers, miscellaneous goods, and light electric parts by injection molding, blow molding, and the like.

〔Example〕

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

Examples 1 to 7 and Comparative Examples 1 to 6 The block copolymers shown in Table 1 were produced according to a conventional method using normal butyl lithium in cyclohexane as a catalyst. For example, the block copolymer D was manufactured as follows. The inside of the dried polymerization vessel equipped with a stirrer was sufficiently replaced with nitrogen gas, and a cyclohexane solution containing 30 parts by weight of purified and dehydrated styrene was charged therein, and then hexane containing 0.07 part by weight of n-butyllithium as a polymerization initiator. After adding the solution, the internal temperature was raised to 70 ° C. to carry out polymerization. After the polymerization of styrene was substantially completed, a cyclohexane solution containing 8.5 parts by weight of styrene and 2 parts by weight of butadiene was used at a constant flow rate for 60 minutes by a plunger pump for 70 minutes.
Added at ° C. Then a cyclohexane solution containing 1.9 parts by weight of butadiene was added. After the polymerization of butadiene was substantially completed, a cyclohexane solution containing 8.5 parts by weight of styrene and 2 parts by weight of butadiene was added with a plunger pump at a constant flow rate for 60 minutes at 70 ° C. Then a cyclohexane solution containing 30 parts by weight of styrene was added. After the polymerization was substantially complete, a small amount of methanol was added to stop the polymerization. Then, 0.5 parts by weight of 2,6-di-tert-butyl-4-methylphenol and 0.5 parts by weight of trisnonylphenylphosphite were added, and then cyclohexane as a solvent was distilled off by heating to obtain a block copolymer D. Obtained.

The block copolymer I was prepared as follows. The purified and dehydrated cyclohexane solution containing 38.5 parts by weight of styrene was charged into the same polymerization vessel as used to produce the block copolymer D, and then a hexane solution containing 0.075 parts by weight of n-butyllithium was added as a polymerization initiator. After that, the internal temperature was raised to 70 ° C. to carry out polymerization. After the polymerization of styrene was substantially completed, a cyclohexane solution containing 23 parts by weight of butadiene was added and polymerization was carried out at 70 ° C. After the polymerization of butadiene was substantially completed, a cyclohexane solution containing 38.5 parts by weight of styrene was added and polymerization was carried out at 70 ° C. After the polymerization was substantially completed, a block copolymer I was obtained by the same treatment as described above.

Then, wax was added according to the compounding method shown in Table 1 and extruded with a 30 mmφ extruder to form a pellet. A plate having a thickness of 2 mm was prepared from the pellet obtained by using an injection molding machine at 210 ° C., and its transparency, color tone, bleeding property and slipperiness were measured. The results are shown in Table 1. The dirt impact value (ASTM D-1709) and tensile modulus (JIS K-6732) of the plate of Example 4 were measured to be 14 kgf · cm, 16500K.
It was g / cm ² , and had excellent impact resistance and rigidity.

Comparative Example 7 A block copolymer having an ABA structure with a styrene content of 55% by weight, a block styrene ratio of 85% by weight, and a molecular weight of 130,000 was obtained in cyclohexane using normal butyllithium as a catalyst. 0.5 W of wax A to this block copolymer
A plate having a thickness of 2 mm was prepared in the same manner as in Example 1 by adding t%.

The tensile modulus of elasticity of the prepared plate (based on JIS K-6732) was 3800 Kg / cm ^2, which was extremely inferior in rigidity.

Comparative Example 8 A block copolymer having an ABA structure having a styrene content of 97% by weight, a block styrene ratio of 90% by weight, and a molecular weight of 170,000 was obtained in cyclohexane using normal butyllithium as a catalyst. 0.5 W of wax A to this block copolymer
Dirt impact value (ASTM D-1
709) was measured and found to be extremely inferior in impact resistance to 1.5 Kgf · cm.

Claims (1)

[Claims] 1. A block copolymer comprising a conjugated diene and a vinyl aromatic hydrocarbon, wherein the vinyl aromatic hydrocarbon content is 60 to 95% by weight, and 100 parts by weight of block copolymer having a melting point of 70 to 120 ° C., microcrystalline wax 0.01
~ 3 parts by weight, a block copolymer composition.