KR20010060421A - Acrylonitrile-butadien-styrene resin composition with improved creep resistence - Google Patents

Abstract

PURPOSE: An acrylonitrile-butadiene-styrene resin composition is provided which significantly improves creep resistance without lowering shock strength and processability. CONSTITUTION: The acrylonitrile-butadiene-styrene resin composition comprises: (i) 30-60 part by weight of a graft copolymer prepared by graft-polymerizing a butadiene rubber with a vinyl cyanide compound and an aromatic vinyl compound; (ii) 0-30 part by weight of a copolymer of a vinyl cyanide compound and an aromatic vinyl compound; and (iii) 10-70 part by weight of a non-linear copolymer which is prepared by copolymerizing 100 part by weight of a vinyl cyanide compound and an aromatic vinyl compound with 0.01-3 part by weight of a mixture consisting of 1-99 part by weight of a multifunctional mercaptan and 99-1 part by weight of a vinyl benzene compound. The acrylonitrile-butadiene-styrene resin composition has an average molecular weight of more than 180,000 and a specific viscosity of more than 0.6.

Description

Acrylonitrile-butadiene-styrene resin composition excellent in creep resistance {ACRYLONITRILE-BUTADIEN-STYRENE RESIN COMPOSITION WITH IMPROVED CREEP RESISTENCE}

The present invention relates to an acrylonitrile-butadiene-styrene resin composition (hereinafter referred to as 'ABS resin composition') having excellent creep resistance, and more particularly to a styrene-acrylonitrile copolymer (hereinafter referred to as 'SAN'). The copolymer is referred to as 'copolymer') and relates to an ABS resin composition that has dramatically improved creep resistance without impairing impact strength and workability.

ABS resin has excellent impact strength, processability and beautiful appearance, and is mainly used as structural materials such as exterior materials and pipes of electronic products. Among the ABS products used as structural materials such as pipes, the impact strength and pressure resistance should be very high. The pressure resistance of resins used in pipes is evaluated as creep resistance, and ISO 9080 defines this method as the maximum pressure of a pipe that can withstand 50 years.

As a way to increase the creep resistance of the resin, there is a method of increasing the SAN content instead of the rubber content, which satisfies the impact strength, which is inherent to the pipe, although the creep resistance may be increased to some extent. It is difficult to make. As another method, there is a method of increasing the molecular weight of the SAN, which may improve creep resistance to some extent, but there is a problem that the viscosity of the resin increases rapidly due to the increase of the molecular weight of SAN, resulting in poor workability. It is difficult to raise the sex to the desired level.

In addition, a number of methods for increasing creep resistance of ABS resins have been proposed.

For example, in US Pat. No. 4,918,159, a method for producing a non-linear styrene resin using a multifunctional mercaptan is proposed. However, when the polyfunctional mercaptan is used alone, the reaction rate is slow and the polymerization reaction proceeds. It is very difficult to control the polymerization reaction such that it becomes unstable and the whole polymerization system hardens.

In addition, Japanese Patent Application Laid-Open No. 59-149912 shows that copolymers made of polyfunctional compounds that can be copolymerized with aromatic vinyl compounds and vinyl cyanide compounds have improved fluidity and mechanical properties, but have no effect on creep resistance. Divinylbenzene exemplified as a multifunctional compound has high reactivity, and thus it is not easy to control the molecular structure of the resin, and creep resistance may be improved unless the weight average molecular weight is 180,000 or more and the intrinsic viscosity is 0.6 or more. There is a problem that can not be.

An object of the present invention is to introduce a SAN copolymer having a non-linear structure when manufacturing the ABS resin composition in order to solve the problems described above, and to produce a non-linear SAN copolymer, the reactivity with divinylbenzene which is highly reactive and easy to gel It is to provide an ABS resin composition which greatly improves the creep resistance by controlling the reactivity by mixing one polyfunctional mercaptan and limiting the range of the weight average molecular weight and the intrinsic viscosity of the polymerized copolymer.

That is, the present invention

(Iii) Graft copolymer prepared by graft polymerization of a vinyl cyanide compound and an aromatic vinyl compound on butadiene rubber

30-60 parts by weight,

(Ii) a copolymer of a vinyl cyanide compound and an aromatic vinyl compound

0-30 parts by weight,

(Iii) A mixture of 1-99 parts by weight of a polyfunctional mercaptan and 99-1 parts by weight of a vinyl benzene compound as a nonlinear copolymer of a vinyl cyanide compound and an aromatic vinyl compound, 10-70 parts by weight of non-linear copolymer, including 3 parts by weight

It is to provide an ABS resin composition produced by copolymerizing a weight average molecular weight of 180,000 or more and intrinsic viscosity of 0.6 or more.

Hereinafter, the present invention will be described in more detail.

In the present invention, the graft copolymer (i) is at least 90% of the rubber particles of 500-3500 kPa, one aromatic vinyl monomer and vinyl cyanide monomer in the presence of 30-70 parts by weight of butadiene rubber having a gel content of 50% or more. A copolymer having a graft rate of 50-100% and a weight average molecular weight of 50,000 to 100,000, obtained by graft copolymerization thereof by adding 30 to 70 parts by weight of one species, by about 30 to 60 parts by weight of the final resin composition. It is preferable to use. Preferred vinyl cyanide compounds here are unsaturated nitrile monomers.

In the present invention, the SAN copolymer (ii) is a copolymer obtained by copolymerizing 50-90 parts by weight of aromatic vinyl monomer and 10-50 parts by weight of vinyl cyanide monomer, and it is preferable to use as much as 0-30 parts by weight of the final resin composition, Preferred vinyl cyanide compounds are unsaturated nitrile monomers.

In the present invention, the nonlinear SAN copolymer (iii) is a nonlinear copolymer obtained by adding a mixture of a polyfunctional mercaptan and a vinylbenzene compound to 50-90 parts by weight of an aromatic vinyl monomer and 10-50 parts by weight of a vinyl cyanide monomer. It is preferable to use only 10-70 weight part of final resin compositions. At this time, the amount of the mixture of the polyfunctional mercaptan and the vinyl benzene compound is 3 parts by weight or less based on 100 parts by weight of the vinyl cyanide compound and the aromatic vinyl compound. In order to improve the pressure resistance of resin, it is preferable that the weight average molecular weights of said nonlinear SAN copolymer are 180,000 or more, and the intrinsic viscosity of a copolymer in tetrahydrofuran solvent is 0.6 or more. If the molecular weight and the intrinsic viscosity are out of the above range, the creep resistance is not significantly improved regardless of the content of the copolymer.

Multifunctional mercaptans that can be used in the non-linear SAN copolymers include trivalent and tetravalent functional mercaptans. Trivalent functional mercaptans include trimetholpropane tri (3-mercaptopropionate), trimetholpropane tri (3-mercaptoacetate), trimetholpropane tri (4-mercaptobutanate), tri Metirolpropane tri (5-mercaptopentanate), trimetholpropane tri (6-mercaptohexaonate), and the tetravalent functional mercaptan is pentaerythritol tetrakis ( 2-Mercaptoacetate), Pentaerythritol Tetraakis (3-Mercaptopropionate), Pantaerythritol Tetrakis (4-Mercaptobutanate), Pentaerythritol Tetrakis (5-Mercaptopentanate) It may be selected from the group consisting of pentaerythritol tetrakis (6-mercapto hexanate), the polyfunctional mercaptan may be used alone or in combination of two or more of the compounds.

Divinylbenzene is preferable as the vinyl benzene compound added to the nonlinear SAN copolymer.

In the present invention, the content of the mixture consisting of the polyfunctional mercaptan and the vinyl benzene compound is 3 parts by weight as described above with respect to 100 parts by weight of the vinyl cyanide compound and the aromatic vinyl compound, preferably 0.01-3 parts by weight, more preferably. Preferably it is 0.1-2 weight part, and the mixing ratio of a polyfunctional mercaptan and a vinyl benzene type compound has a ratio of 99-1 weight part of a vinyl benzene type compound with respect to 1-99 weight part of polyfunctional mercaptans. If the content of the mixture is less than 0.01 parts by weight, the creep resistance is not significantly improved, and when the content of the mixture is more than 3 parts by weight, gelation proceeds and cannot be used.

When the weight average molecular weight of the non-linear SAN copolymer is less than 180,000 or the intrinsic viscosity is less than 0.6 in a tetrahydrofuran solvent, the elongation is not markedly improved, and the allowable weight average molecular weight and the upper limit of the intrinsic viscosity are different depending on the application. The range of weight average molecular weight and intrinsic viscosity is not limited unless gelation proceeds sufficiently as it may be applied.

As described above, the non-linear SAN copolymer is copolymerized by adding a mixture of polyfunctional mercaptan and vinyl benzene compound as 50-90 parts by weight of an aromatic vinyl monomer and 10-50 parts by weight of an unsaturated nitrile monomer. As the obtained nonlinear SAN copolymer, it is preferable to use only 10-70 parts by weight of the final resin composition, but if it is out of this range, improvement in creep resistance cannot be expected.

The acrylonitrile-butadiene-styrene resin composition of the present invention may add necessary inorganic additives, heat stabilizers, antioxidants, light stabilizers, pigments and dyes in addition to the above components.

The present invention will be described with reference to the following examples, and the following examples are only described for the purpose of illustrating the present invention and are not intended to limit the protection scope of the present invention.

Preparation Example 1. Preparation of Graft Copolymer (i)

Butadiene rubber latex having a particle size of 0.3 μm was added in an amount of 50 parts by weight of butadiene based on the entire monomer, 150 parts of deionized water, 0.9 parts of rosin soap, 0.3 parts by weight of cumene hydroperoxide, and 0.2 mercaptan chain transfer agent. After adding 0.3 parts of glucose and glucose, the internal temperature was maintained at 70 ° C. 35 weight part of styrene and 15 weight part of acrylonitrile were dripped here for 3 hours, and superposition | polymerization was advanced by redox initiation, and the styrene- acrylonitrile- butadiene graft copolymer latex was produced. The styrene-acrylonitrile-butadiene graft copolymer latex was solidified in 1.5% magnesium sulfate aqueous solution and dried to prepare a styrene-acrylonitrile-butadiene graft copolymer resin in powder form.

Preparation Example 2. Nonlinear SAN copolymer (iii)

Styrene monomer 71 parts by weight, acrylonitrile monomer 29 parts by weight, ion exchange water 150 parts, tricalcium phosphate 0.4 parts, carboxylic acid anionic surfactant 0.03 parts, polyoxyethylene alkyl ether phosphate ester 0.01 parts, polyfunctional mercaptan 0.1-1 part by weight of a trivalent trimetholpropane tri (3-mercaptopropionate) as a polymer, 0.1-1 part by weight of divinylbenzene, and 0.1-1 part by weight of 2,2'-azobisisobutylonitrile as an initiator. After mixing and adding the parts, the reactor was completely sealed, and then sufficiently stirred and dispersed, and then the internal temperature of the reactor was raised to proceed with polymerization at 75 ° C. for 6 hours. Thereafter, the inside of the reactor was cooled to room temperature again to terminate the reaction, and the polymer prepared above was washed, dehydrated, and dried to obtain a bead copolymer.

In the following examples and comparative examples, the SAN copolymer (ii) used SAN HR-5330 manufactured by Cheil Industries.

Examples 1-3 and Comparative Examples 1-6

The composition of each component used in Example 1-3 and Comparative Example 1-6 is shown in Table 1. In Example 1-3, the resin composition of the present invention was used, and in Comparative Example 1-6, the nonlinear SAN copolymer was not used. The resins used in Examples 1-3 and Comparative Examples 1-6 were uniformly mixed with a Henschel mixer and then extruded into a twin screw extruder to pelletize. Pipes were manufactured by extrusion molding the specimens obtained as described above.

The impact strength and creep resistance of the test pieces of the resin composition prepared according to Examples 1-3 and Comparative Examples 1-6 were evaluated. The results are shown in Table 2.

Sequence number / item Component (i) Component (ii) Component (iii) Example One 40 10 50 2 45 10 45 3 50 10 40 Comparative example One 10 90 0 2 20 80 0 3 30 70 0 4 40 60 0 5 45 55 0 6 50 50 0

★ The above figures are based on parts by weight (wt%).

Sequence number / item IZOD impact strength Creep Resistance (Mpa) Example One 40 17.5 2 45 17.0 3 50 16.5 Comparative example One 12 15.0 2 18 14.5 3 32 14.0 4 40 13.5 5 45 12.5 6 50 12.0

[Property evaluation method]

* Impact strength: measured by the method of ASTM D256.

* Creep resistance (pressure resistance): The creep resistance (pressure resistance) of plastic pipe is measured by indirect measurement of hoop stress for 50 years according to ISO 9080.

As confirmed through the results of Table 2, the acrylonitrile-butadiene-styrene copolymer resin composition of the present invention has the advantage that the creep resistance of the resin composition is improved as a result of using the non-linear structure SAN copolymer in preparing the resin composition. Has

Claims (3)

(Iii) Graft copolymer prepared by graft polymerization of a vinyl cyanide compound and an aromatic vinyl compound on butadiene rubber 30-60 parts by weight, (Ii) a copolymer of a vinyl cyanide compound and an aromatic vinyl compound 0-30 parts by weight, (Iii) A mixture of 1-99 parts by weight of a polyfunctional mercaptan and 99-1 parts by weight of a vinyl benzene compound as a nonlinear copolymer of a vinyl cyanide compound and an aromatic vinyl compound, 10-70 parts by weight of non-linear copolymer, including 3 parts by weight Acrylonitrile-butadiene-styrene resin composition prepared by copolymerizing a weight average molecular weight of 180,000 or more and an intrinsic viscosity of 0.6 or more The method of claim 1, wherein the multifunctional mercaptan of the component is trimetholpropane tree (3-mercaptopropionate), trimetholpropane tree (3-mercaptoacetate), trimetholpropane tree Trivalent functional mercaptans or pentaerythritol, such as (4-mercaptobutanate), trimetholpropane tri (5-mercaptopentanate), and trimetholpropane tri (6-mercaptohexaonate) Tetrakis (2-Mercaptoacetate), Pentaerythritol Tetraakis (3-Mercaptopropionate), Pantaerythritol Tetrakis (4-Mercaptobutanate), Pentaerythritol Tetrakis (5-Mercapto) Acrylonitrile-butadiene-styrene, which is selected from tetravalent functional mercaptans or mixtures of trivalent or tetravalent functional mercaptans such as pentanate), pentaerythritol tetrakis (6-mercaptohexanate) Resin composition. The acrylonitrile-butadiene-styrene resin composition according to claim 1, wherein the aromatic vinylbenzene compound is divinylbenzene.