JPH0619005B2 - Thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. TECHNICAL FIELD The present invention relates to a thermoplastic resin composition having excellent heat resistance and impact resistance, more specifically, a polycarbonate resin, an aromatic vinyl compound-conjugated diene block copolymer (hereinafter,
(Abbreviated as block copolymer) and a maleimide-based copolymer.

b. 2. Description of the Related Art Polycarbonate resins are widely known as engineering plastics having excellent impact resistance and heat resistance.

However, in impact resistance, notch sensitivity is sensitive,
If the molded product has a cut or the like, it has a drawback that it is easily broken by stress.

As a method of improving this, blend a polycarbonate resin with a rubber-reinforced styrene resin, for example, an ABS resin,
Resins having high impact resistance and improved notch sensitivity have been developed and are commercially available. However, the resin has low heat resistance and may not be sufficient as a material for parts of automobiles and OA equipment.

c. Problems to be Solved by the Invention As described above, it has been difficult to produce an engineering plastic excellent in heat resistance and impact resistance by the conventional method.

Therefore, as a result of intensive investigations by the present inventors, a resin composition having excellent heat resistance and impact resistance was obtained by mixing a maleimide copolymer with a polycarbonate resin and an aromatic vinyl-conjugated diene block copolymer. They have found that they can be obtained and have reached the present invention.

d. Means for Solving the Problems That is, the present invention provides (a) a polycarbonate resin 5 to 90% by weight, (b) an aromatic vinyl-conjugated diene block copolymer 3 to 40% by weight, and (c) a rubbery polymer. In the presence or absence of a maleimide compound and a thermoplastic resin composition consisting of a maleimide copolymer 5 to 85 wt% obtained by polymerizing a monomer mixture containing an aromatic vinyl compound as a main component. It is provided.

Examples of the polycarbonate resin (a) used in the present invention include aromatic polycarbonate, aliphatic polycarbonate, and aliphatic-aromatic polycarbonate. For example, polymers composed of bisphenols such as 2,2-bis (4-oxyphenyl) alkane-based, bis (4-oxyphenyl) ether-based, bis (4-oxyphenyl) sulfone sulfide or sulfoxide-based,
Alternatively, it may be a copolymer, and may be a polymer using bisphenols substituted with halogen depending on the purpose. With regard to the type of polycarbonate resin (a), the manufacturing method, etc., all those described in detail in "Polycarbonate resin" published by Nikkan Kogyo Shimbun Co., Ltd. (issued September 30, 1969) can be used.

The content of the polycarbonate resin (a) in the resin composition of the present invention is 5 to 90% by weight, preferably 10 to 80% by weight. If it is less than 5% by weight, the heat resistance of the obtained resin composition is low, and if it is 90% by weight or more, the impact resistance (impact with notch) is low.

The aromatic vinyl compound-conjugated diene-based block copolymer (b) used in the present invention (hereinafter, referred to as block copolymer (b)) is a block copolymer of an aromatic vinyl compound and a conjugated diene, The amount used is 3-40% by weight, preferably 5-30% by weight, based on the total composition. If it exceeds 40% by weight, the heat resistance aimed at by the present invention decreases, and if it is 3% by weight or less, the impact resistance decreases, which is not preferable.

The aromatic vinyl compound constituting the block copolymer (b) is styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, dibromostyrene, α-methylstyrene, α-ethylstyrene, methyl-α. -Methylstyrene, dimethylstyrene, vinylnaphthalene and the like. Of these, styrene, p-methylstyrene and α-methylstyrene are preferable, and styrene, α-methylstyrene and a mixture thereof are more preferable.

On the other hand, examples of the conjugated diene compound include butadiene,
Examples include isoprene and piperylene. Of these, preferred are butadiene and isoprene.

The preferred block copolymer (b) used in the present invention, the following general formula Is a block copolymer having a total aromatic vinyl compound content of 25 to 90% by weight, preferably 28 to 90% by weight.

Particularly preferred block copolymer (b) is one having the following structure, and when this block copolymer is used, further excellent impact resistance improvement can be expected.

That is, a block copolymer having an aromatic vinyl compound content of 25 to 95% by weight, wherein the copolymer has the general formula And the content of the aromatic vinyl compound constituting a chain in which one or four or less of the aromatic vinyl compound are connected in a monomer unit is 1 to 4 of the whole aromatic vinyl compound.
25% by weight, preferably 2 to 20% by weight, more preferably 5 to 20% by weight.

Further, the preferable number of the tapered blocks is 2 to 7.

The block copolymer (b) used in the present invention can be produced, for example, by the following method.

An ether or a tertiary amine is added to a hydrocarbon solvent, an aromatic vinyl compound is first polymerized using an organic lithium compound as a polymerization initiator, and after the polymerization reaction is substantially completed, a conjugated diene compound or aromatic The mixture of the vinyl compound and the conjugated diene compound is preferably added in 2 to 10 times and polymerized, and if necessary, after that, the same amount of conjugated diene as one addition is added for polymerization.

Further, the block copolymer represented by the general formula A-B-A can be obtained by adding an aromatic vinyl compound and then polymerizing.

Further, the block copolymer having the structure represented by the general formula (AB) _n X can be obtained by subsequently performing a coupling reaction using a conventionally known coupling agent such as tetrachlorosilane.

The mixture of the conjugated diene of the above aromatic vinyl compound is 2 to
In the step of adding and polymerizing in 10 batches, the addition amount of the monomer in each time is preferably the same, and as a method of adding the monomer, a method of adding a monomer mixture, or a conjugated diene The aromatic vinyl compounds may be added separately and simultaneously.

The preferred chain distribution of the aromatic vinyl compound in the block copolymer (b) is 0.005 to 5 parts by weight, preferably 0.005 to 0.5 parts by weight of ether or tertiary amine in a hydrocarbon solvent per 100 parts by weight of the monomer. It is obtained by adding parts by weight.

The weight average molecular weight of the block copolymer (b) used in the present invention is 10,000 to 800,000, preferably 50,000 to 500,000.
If it is less than this range, improvement in impact resistance cannot be expected, and if it is more than this range, the compatibility with the components (a) and (c) deteriorates, which is not preferable.

As the hydrocarbon solvent used in the production of the block copolymer (b), cyclopentadiene, cyclohexane, benzene, xylene and mixtures thereof with pentahexane, heptane, butane and the like are used.

Further, as the organic lithium compound, n-butyllithium, sec-butyllithium, tert-butyllithium, n
-Hexyllithium, iso-hexyllithium, phenyllithium, naphthyllithium, etc. are used.

The maleimide copolymer (c) used in the present invention is a copolymer obtained by polymerizing a monomer mixture containing a maleimide compound and an aromatic vinyl compound as main components in the presence or absence of a rubbery polymer. It is a polymer.

Examples of the rubbery polymer include polybutadiene (BR), styrene-butadiene rubber (SBR), diene rubber such as acrylonitrile-butadiene rubber (NBR), ethylene-propylene rubber (EPR), ethylene-propylene-non-conjugated diene rubber (EDPM). ) And other olefinic rubbers, and polybutyl acrylate and other acrylic rubbers.

The content of the rubbery polymer in the copolymer (c) is not particularly limited.

Examples of the maleimide compound used in the present invention include maleimide, N-methylmaleimide, N-ethylmaleimide, N-phenylmaleimide, N-o-chlorophenylmaleimide, N-cyclohexylmaleimide, and the like, but preferably N- Phenylmaleimide, No
-Chlorophenylmaleimide, N-cyclohexylmaleimide and the like, and these may be used alone or in combination of two or more.

Examples of the aromatic vinyl compound include styrene, α-methylstyrene, methylstyrene, monobromostyrene, dibromostyrene and the like, and they are used alone or in combination of two or more. The preferred aromatic vinyl compound is styrene.

The maleimide-based copolymer (c) of the present invention contains the above maleimide-based and aromatic vinyl compounds as main components, but may contain other copolymerizable components.

Other copolymerizable monomers include, for example, vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, methacrylic acid esters such as methyl methacrylate and ethyl methacrylate, maleic anhydride, and itaconic anhydride. Examples thereof include saturated acid anhydrides.
These are used alone or in combination of two or more.

Specific combinations of monomers that can be copolymerized with these maleimide-based monomers are illustrated below.

Styrene Styrene-acrylonitrile styrene, acrylonitrile-methyl methacrylate By substituting α-methylstyrene for a part or all of these styrenes, a maleimide copolymer having high heat resistance can be obtained.

Further, flame retardancy can be imparted by substituting a part or all of styrene with halogenated styrene.

In the present invention, the preferred polymerization method for obtaining the maleimide copolymer (c), a monomer mixture mainly composed of a rubbery polymer and a maleimide compound and an aromatic vinyl compound, a homogeneous solution polymerization system To continuously polymerize. A bulk polymerization method, a solution polymerization method and the like are suitable as the polymerization method, and the polymerization solvent and the polymerization temperature can be the same as those in the general radical polymerization of vinyl monomers.

The content of the maleimide copolymer (c) in the resin composition of the present invention is 5 to 85% by weight, preferably 10 to 70% by weight. Heat resistance is low at less than 5% by weight, 85% by weight
The above is not preferable because the impact resistance is low.

The method for preparing the thermoplastic molding composition of the present invention is a method of dissolving and swelling each component in an organic solvent and mixing them.

A method in which the components are mixed with a mixer, etc., the solution is mixed with an extruder, and then pelletized.

In the method of 1., the powder mixture recovered using a non-solvent is melt-mixed using an extruder and then pelletized.

There is a method in which the pellets or powder obtained by the method (1) are used alone or in a mixture, or each component is further added and mixed, and then a molded product is obtained using an injection molding machine.

In each of the above methods, known mixing equipment such as Banbury and kneader can be used.

Furthermore, to the resin composition of the present invention obtained by the above method, other thermoplastic resin, styrene resin, polyphenylene ether, polyamide, polyester, acrylic resin or other polymer is added and mixed, this in an extruder The composition may be obtained by melt mixing.

The thermoplastic molding composition of the present invention can be used as various molded articles by injection molding, sheet extrusion, vacuum molding, modified molding, foam molding and the like.

When the thermoplastic molding composition of the present invention is used, known antioxidants, ultraviolet absorbers, lubricants, flame retardants, antistatic agents, foaming agents, glass fibers and the like which are commonly used can be added.

The thermoplastic molding composition of the present invention can be suitably used for automobile parts, electric products, household products, various industrial products and the like.

e. EXAMPLES Next, the present invention will be described in more detail with reference to production examples and examples, but these are merely examples and do not limit the content of the present invention. In the following examples, parts and% indicate parts by weight and% by weight, respectively.

Production Example (1) Aromatic vinyl compound-conjugated die block copolymer B-1 Washed and dried stirrer and jacketed autoclave were charged with 4500 g of cyclohexane and 1 g of tetrahydrofuran under a nitrogen atmosphere, and then the internal temperature was raised to 70 ° C. did.

Next, after adding a hexane solution containing 0.5 g of n-butyllithium, 130 g of styrene was added and polymerization was carried out for 60 minutes. The polymerization conversion of styrene was 100%. Then styrene 15
g and 115 g of butadiene were added, and the mixture was polymerized for 60 minutes. The polymerization conversion rate of styrene and butadiene was 100%. Further, this operation was repeated twice. Next, 115 g of butadiene was added and polymerized to a polymerization conversion rate of 100%.
After that, 130 g of styrene was further added and polymerized for 60 minutes to obtain a block copolymer B-1 shown in Table 1.

B-2, B-3 Next, using a sample in which the amount of styrene of the block copolymer B-1 was changed, and by the same method as in B-1 above, Table 1
B-2 and B-3 shown in FIG.

(2) Maleimide Copolymer A maleimide copolymer having the following composition was prepared.
(Table-2) Examples 1 to 16 and Comparative Examples 1 to 6 Various polymers were mixed according to the composition ratios shown in Table 3 and extruded at a temperature of 260 to 300 ° C. using a biaxial kneader to form pellets. Dry and use injection molding machine 24
Test pieces were molded at 0-280 ° C. Table 3 shows the results of evaluation of the properties of these using the following methods.

(1) Heat resistance According to ASTM D648, using a test piece with a thickness of 1/2 ″, 26
Measured at 4 psi.

(2) Impact resistance: Measured according to ASTM D256 using a test piece with a 1/4 "notch thickness.

Hereinafter, the resin compositions obtained in Examples and Comparative Examples will be described while comparing the properties shown in Table-3.

The resin compositions of Examples 1 to 6 and Comparative Examples 1 and 2 are obtained by varying the amount of polycarbonate.
Indicates a case where the amount of polycarbonate resin is outside the range of the present invention, and Comparative Example 1 has a low impact resistance because the amount of polycarbonate resin is larger than the range of the present invention. Further, in Comparative Example 2, since the amount of polycarbonate resin is small, the heat resistance is low.

The resin compositions of Examples 7 and 8 and Comparative Examples 3 and 4 were obtained by varying the block copolymer amount. In Comparative Example 3, the content is more than the range of the present invention, and the heat resistance is low. Comparative Example 4 is less than the range of the present invention and has low impact resistance.

The resin compositions of Examples 9 and 10 show the case where the types of block copolymers are different.

The resin compositions of Examples 11 to 16 are different in the type of maleimide-based copolymer.

The resin compositions of Comparative Examples 5 and 6 are cases where the amount of the maleimide copolymer is outside the range of the present invention. Comparative Example 5 is a case where the maleimide-based copolymer is not included and the heat resistance is low. Comparative Example 6 is a case where the amount of the maleimide-based copolymer is larger than the range of the present invention and the body impact resistance is low.

f. EFFECTS OF THE INVENTION Currently, automobiles and low-power manufacturers that use thermoplastic resins tend to become complicated and large in size due to diversified applications.

Molded articles for such applications are required to have much higher heat resistance and impact resistance than ever before.

However, with conventional polycarbonate / ABS compositions,
Not enough for these requirements.

Since the resin composition of the present invention has a high balance of heat resistance and impact resistance,
It is a material that improves the drawbacks of the above composition and satisfies the requirements of the above manufacturers, and its industrial value is great.

Claims (2)

[Claims] 1. (a) Polycarbonate resin 5 to 90% by weight (b) Aromatic vinyl-conjugated diene block copolymer 3
To 40% by weight and (c) the presence or absence of a rubbery polymer, a maleimide copolymer obtained by polymerizing a monomer mixture containing a maleimide compound and an aromatic vinyl compound as a main component.
A thermoplastic resin composition comprising 85% by weight. 2. An aromatic vinyl-conjugated diene-based block copolymer has the following general formula: The thermoplastic resin composition according to claim (1), which is a block copolymer having a total aromatic vinyl compound content of 25 to 90% by weight.