JPH06322202A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain a thermoplastic resin composition excellent in a balance between impact resistance and processability. CONSTITUTION:A thermoplastic resin composition prepared by dispersing a graft copolymer prepared by grafting both an aromatic vinyl monomer (STY) and a vinyl cyanide monomer (ACN) or these monomers and other copolymerizable vinyl monomers (other vinyls) onto a rubbery diene polymer (PBDE) in a copolymer prepared by copolymerizing STY and ACN or copolymerizing these monomers with other vinyls, wherein (1) the number-mean particle diameter of PBDE is in the range of 0.08-1.00mum, (2) the compositional. ratio in the composition is 5-40wt.% PBDE, 30-90wt.% STY, 5-50wt.% ACN, and 0-40wt.% other vinyls, (3) the relaxation time (T2,a) of the most quickly damping component of PBDE is 300-800musec, and (4) the rate of the most quickly damping component of PBDE [100Ma/(Ma+Mb+Mc)] is 30-90<1>H%, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition containing a rubbery polymer having a specific structure and having an excellent balance of impact resistance and processability.

[0002]

"Graft polymer" in which vinyl cyanide and aromatic vinyl are grafted onto a diene rubber polymer.
However, ABS resin with a sea-island structure dispersed in a "copolymer" of vinyl cyanide and aromatic vinyl is widely used because of its good mechanical properties including impact resistance and processability. Although being used, it is desired to develop an ABS resin having an excellent balance of impact resistance and workability as the range of use is expanded. Conventionally, by increasing the amount of the rubber component in the ABS resin or increasing the molecular weight of the copolymer,
Although the impact resistance is improved, the workability is rather reduced. Therefore, as a method of improving the utilization efficiency of the rubber component, that is, a method of obtaining sufficient impact resistance and excellent processability with a small amount of the rubber component, a method of using two kinds of rubbers having different particle diameters or a particle diameter Not only the graft ratio is different 2
Although a method of preparing a kind of graft polymer has been proposed,
It is hard to say that it has a sufficient impact resistance-workability balance. Recently, with the development of analysis and analysis technology, it has been disclosed in JP-A-3-7710, etc. that the spin-spin relaxation time by the Harn-Eco method using a pulsed NMR apparatus influences the physical properties of a rubber-reinforced resin. However,
A composition having a sufficient physical property balance cannot be obtained only by such relaxation time limitation, and it is a fact that development of an ABS resin having an excellent impact resistance-processability balance is desired.

[Problems to be Solved by the Invention]

The present invention is to solve the above problems and to provide a thermoplastic resin composition having a more excellent impact resistance-workability balance.

[Means for solving problems]

The present inventor has paid attention to the structure of the rubber component, which has a great influence on the impact resistance of the ABS resin, and as a result of diligent research, as a result, not only the particle diameter of the rubber component but also the harsh economies using a pulse NMR apparatus. - three relaxation time obtained by law _{(T 2, a, T 2} , b, T 2, c) among the component ratio [10 take the relaxation time of the component for attenuating the fastest (T _{2, a)}
0M _a ÷ (M _a + M _b + M _c )], an ABS resin using a rubber component in a certain range is a conventional ABS resin.
The present invention has been found to have a better impact resistance-processability balance than resins, and has reached the present invention.

That is, according to the present invention, a diene rubber polymer is grafted with an aromatic vinyl monomer and a vinyl cyanide monomer or a copolymerizable vinyl monomer with them. The graft polymer is dispersed in a copolymer formed by copolymerizing an aromatic vinyl monomer and a vinyl cyanide monomer or a copolymerizable vinyl monomer with them. In the thermoplastic resin composition, the diene rubbery polymer has a number average particle size of 0.08 to 1.00 μm,
The composition ratio in the composition is 5 to 40% by weight of diene rubbery polymer, 30 to 90% by weight of aromatic vinyl monomer, 5 to 50% by weight of vinyl cyanide monomer, and other copolymerizable Vinyl monomer of 0 to 40% by weight, relaxation time (T _{2, a} ) of the fastest decaying component of the diene rubbery polymer is 300.
~ 800 μsec, and ratio of such components [100M
there is provided a _{a ÷ (M a + M b} + M c) ] is thermoplastic resin composition excellent in processability balance between the impact resistance is 30 to 90 ¹ H%.

The present invention will be described in detail below. Examples of the diene rubbery copolymer used in the present invention include polybutadiene, styrene-butadiene copolymer,
Examples thereof include acrylonitrile-butadiene copolymer, polyisoprene, and the like, and one kind or two or more kinds can be used. Especially polybutadiene and styrene content is 2
A styrene-butadiene copolymer content of 0% by weight or less is preferred. The number average particle diameter of the diene rubbery copolymer is 0.0
It is 8 to 1.00 μm. If it is less than 0.08 μm, the impact resistance is poor, and if it exceeds 1.00 μm, the impact resistance and the gloss are poor, which is not preferable. Particularly, 0.10 to 0.50 μm is preferable. The particle size can be adjusted by increasing or decreasing the amount of emulsifier. Generally, the particle size decreases as the amount of emulsifier increases.

Aromatic vinyl monomers constituting the thermoplastic resin composition together with the diene rubbery copolymer include styrene, α-methylstyrene, o-methylstyrene and m.
-Methylstyrene, p-methylstyrene, t-butylstyrene, α-methylvinyltoluene, dimethylstyrene, chlorostyrene, dichlorostyrene, bromstyrene, dibromostyrene, vinylnaphthalene, etc. are used, and one or more kinds thereof are used. You can In particular, styrene and α-methylstyrene are preferable. Further, examples of the vinyl cyanide-based monomer include acrylonitrile, fumaronitrile, methacrylonitrile, and the like, and one kind or two or more kinds can be used. Acrylonitrile is particularly preferable. Other copolymerizable vinyl monomers include methyl (meth) acrylate and ethyl (meth)
Unsaturated carboxylic acid alkyl ester monomers such as acrylate, propyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, maleimide, methylmaleimide, ethylmaleimide, N-phenylmaleimide, O-chloro-N-phenylmaleimide, etc. The maleimide-based monomer and the like can be used, and each can be used alone or in combination of two or more.

The thermoplastic resin composition of the present invention comprises 5 to 40% by weight of a diene rubbery polymer and 3 aromatic vinyl monomers.
0 to 90% by weight, vinyl cyanide-based monomer 5 to 50% by weight, and other copolymerizable vinyl-based monomer 0 to 40% by weight. Outside this range, the balance between impact resistance and workability is poor. In particular, diene rubbery polymer 15 to 30
A composition of wt%, aromatic vinyl monomer 40 to 70 wt%, vinyl cyanide monomer 15 to 30 wt% and other copolymerizable vinyl monomer 0 to 30 wt% is preferable. .

In the thermoplastic resin composition of the present invention, a graft polymer (1) obtained by grafting a monomer onto a diene rubbery polymer is dispersed in a copolymer (2) composed of the monomer. Has become. The copolymer (2) may be simultaneously produced at the time of graft polymerization, or may be separately copolymerized with only a monomer. The graft ratio of the graft polymer is
There is no particular limitation, but from the viewpoint of impact resistance and workability, it is 20-
70% by weight, particularly 30 to 60% by weight is preferred. In addition,
The graft ratio (%) can be determined according to the following equation (1) by extracting and separating the soluble portion and the insoluble portion using acetone as a solvent.

[0010]

[Equation 1]

The molecular weight of the copolymer (controlled by the intrinsic viscosity) is not particularly limited, but from the viewpoint of impact resistance and processability, the intrinsic viscosity (30 ° C., dimethylformamide) is 0.4 to 0. It is preferably 8. The graft polymerization method and the copolymerization method are not particularly limited, and examples thereof include known emulsion polymerization methods, suspension polymerization methods, solution polymerization methods, bulk polymerization methods, and combinations thereof. The emulsion polymerization method is particularly preferable.

Further, in order to achieve the object of the present invention, it is important to define not only the rubber particle diameter and the composition ratio but also the rubber structure. That is, the relaxation time (T _{2, a} ) of the fastest decaying component of the diene rubbery polymer is 300 to 800 μse.
c, and the proportion of such components _{[100M a ÷ (M a + M} b
+ M _c )] is in the range of 30 to 90 ¹ H%. The relaxation time (T _{2, a} ), using a pulsed NMR apparatus, measurement nucleus: hydrogen nucleus, measurement frequency: 60 μHz, 90 °
Pulse width: 4 μsec, temperature: measured under the conditions of 60 ° C., and measured by the Hahn-Echo Metho method.
d, 90 ° -τ-180 ° pulse method), the free decay curve (M (t)) of the magnetization of the rubber component is measured, and then the free decay curve is obtained.
Component, ie, three relaxation times (T _{2, a} , T _{2, b} , T
_{2, c} ) exists. The following equation (2) is calculated by the nonlinear least squares method.
Means the relaxation time of the fastest decaying component when separated into three components. The ratio of components to attenuate fastest is sought from the expression of _{100M a ÷ (M a + M} b + M c), expressed by the amount of hydrogen nuclei ⁽¹ H%).

[0013]

(2) M (t) = Ma exp (-t / T _{2, a} ) + Ma exp (-
t / T _{2, b} ) ＋ Ma exp (-t / T _{2, c} )

M (t): Free decay curve of magnetization t: Time (μsec) T _{2, a} , T _{2, b} , T _{2, c} : Relaxation time (T ₂ ) of each component
In, and _{T 2, a <T 2,} b <T 2, c M a, M b, M c: T 2, a, T 2, b, the magnetization of the components corresponding to T _{2, c}

If the relaxation time (T _{2, a} ) and the proportion of the fastest decaying component are outside the above ranges, the impact resistance of the composition will not be improved. Particularly preferably, the relaxation time (T _{2, a} ) 4
00-750 μ. ec, ratio of the fastest decaying component 4
It is 0 to 80 ¹ H%. The relaxation time and the ratio of the component that decays the fastest can be adjusted by the polymerization time during the production of the diene rubber polymer, the type and amount of the molecular weight modifier, and the like. By increasing the polymerization time, the relaxation time and (T _{2, a} ) as well as the proportion of the fastest decaying component tend to decrease. Moreover, the relaxation time and its ratio tend to increase as the amount of the molecular weight modifier increases.

In the thermoplastic resin composition of the present invention, if necessary, an antioxidant, an ultraviolet absorber, an antistatic agent, a lubricant,
Known additives such as dyes and pigments, as well as glass fiber,
Known reinforcing agents such as metal fibers and carbon fibers can be added. The graft polymer and the copolymer, or the mixture of the above-mentioned additives and reinforcing agents can be used with a known mixer such as a Banbury mixer, a single screw extruder, or a twin screw extruder.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples. All parts and% used in the examples are based on weight.

Reference Example Manufacture of Polybutadiene Latex 100 parts of butadiene, potassium rosinate (emulsifier), potassium persulfate (initiator), dodecyl mercaptan (molecular weight modifier) and deionized water 20 in a reactor substituted with nitrogen.
0 part was charged and reacted at 60 ° C. Emulsifier, initiator,
By changing the molecular weight modifier and the reaction time, 13 kinds of polybutadiene having different structures such as particle size were prepared. The polymerization conditions of the polybutadiene latex are shown in Table 1, and the particle size and structure are shown in Table 2.

Examples 1 to 7 and Comparative Examples 1 to 6 100 parts (solid content) of the polybutadiene latex obtained in Reference Example and 0.5 dextrin were placed in a reactor substituted with nitrogen.
65 parts, sodium pyrophosphate 0.3 parts, ferrous sulfate 0.005 parts and deionized water 100 parts,
After the temperature was raised to ℃, cumene hydroperoxide 0.1
Part, 0.3 part of t-dodecyl mercaptan, 150 parts of acrylonitrile and 350 parts of styrene, and 2 parts of sodium oleate and 2 parts of deionized water.
An emulsifier solution consisting of 0 parts was continuously added over 5 hours. Then, the inside of the reaction system was further heated to 68 ° C. and aged for 2 hours to complete the polymerization. After completion of the polymerization, salting out was performed using magnesium sulfate, and dehydration and drying were performed to obtain a thermoplastic resin composition. To the obtained powder, 0.2 parts of a phenolic stabilizer and 1.0 part of ethylene bisstearamide were added, pelletized by an extruder, and then injection molded at 230 ° C. to prepare various test pieces. .

[0020]

The physical properties of the composition were measured by the following methods. The results are shown in Table-2. (1) Preparation of Test Pieces for Measurement The pellets obtained in Examples and Comparative Examples were molded into test pieces for each physical property at a cylinder set temperature of 230 ° C. using a 3.5 ounce injection molding machine. (2) Physical property measurement Impact resistance Notched Izod impact strength (NI) ASTM D-
According to 256. 1/4 inch thick, 23 ° C, unit: Kg
cm / cm Workability High performance type flow tester, 210 ° C, 30 Kg / cm ² ,
Unit: cc / min (3) Number average molecular weight Polybutadiene latex was dyed with osmium tetroxide, 500 rubber particle diameters were measured by a transmission electron microscope (TEM), and the average value was calculated. (4) Relaxation time (T _{2, a} ) and its ratio Using a pulsed NMR apparatus, measurement nucleus: hydrogen nucleus, measurement frequency: 60 μHz, 90 ° pulse width: 4 μsec, temperature:
Measured under the condition of 60 ° C., and measured by the Hahn eco method (Hahn-
Free decay curve (M (t)) of the magnetization of the rubber component is measured by Echo Method, 90 ° -τ-180 ° pulse method). Three relaxation times (T _{2, a} , T on the free decay curve)
_{2, b} , T _{2, c} ) The relaxation time of the fastest decaying component when separated into 3 components is calculated according to the above equation (2) based on the nonlinear least squares method. Also, the fastest rate of decaying component ⁽¹ H%) _{is, 100M a ÷ (M a +} M b + M
_{It was calculated} from the equation in _c ).

[0022]

[0023]

INDUSTRIAL APPLICABILITY The thermoplastic resin composition of the present invention has an excellent balance of impact resistance and workability, and can be used in the fields of vehicle parts, electric parts, sundries, and the like, and its excellent performance. By utilizing the above, it is possible to obtain a molded product which is thinner and larger than before.

Claims (1)

[Claims] 1. A graft polymer obtained by grafting an aromatic vinyl monomer and a vinyl cyanide monomer or a copolymerizable vinyl monomer thereof with a diene rubber polymer. Is a thermoplastic resin composition obtained by dispersing an aromatic vinyl-based monomer and a vinyl cyanide-based monomer or a copolymer formed by copolymerizing them with another copolymerizable vinyl-based monomer. In the product, the number average particle diameter of the diene rubber polymer is 0.08 to
1.00 μm, the composition ratio of the composition is diene rubbery polymer 5-40
% By weight, aromatic vinyl-based monomer 30 to 90% by weight, vinyl cyanide-based monomer 5 to 50% by weight, other copolymerizable vinyl-based monomer 0 to 40% by weight, diene rubber material component of the relaxation time of the fastest decay of the polymer (T _{2, a)} is 300～800Myusec, and the proportion of component fastest decay of diene-based rubbery polymer _{[100M a ÷ (M a + M} b + M c) ] 30 to 90 ¹
The thermoplastic resin composition is H%.