JPH09100389A - Thermoplastic resin composition having excellent thermal stability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a thermoplastic resin compsn. which has excellent thermal stability during residence in a molding machine and is less likely to deteriorate properties during extrusion and molding. SOLUTION: This thermoplastic resin compsn. comprises: 40 to 95 pts.wt. polycarbonate resin; and 5 to 60 pts.wt. rubber-toughened resin wherein, in the preparation of a rubber-toughened resin, contg. a graft copolymer by graft- copolymerizing at least one vinyl compd. onto a rubber polymer, an alkaline earth metal salt is used as a coagulating agent and coagulation is conducted while maintaining pH in the range of from 6 to 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition containing a polycarbonate resin having excellent thermal stability.

[0002]

2. Description of the Related Art Blend compositions of polycarbonate and a rubber-reinforced resin such as ABS resin are excellent in mechanical properties and heat resistance, and they are OA for electric appliances, computers and word processors.
Widely used as a housing material for equipment. In addition, such a blend composition is often required to be recyclable from the viewpoint of effective use of resources.

However, polycarbonate and ABS
Since a blended composition of a rubber-reinforced resin such as a resin is inferior in thermal stability at the time of staying in a molding machine or an extruder, a molded piece after staying may have lower impact resistance or lower recyclability. In addition, it was necessary to devise extrusion conditions and molding conditions such as keeping the residence time as short as possible, and to increase the proportion of virgin resin during recycling.

As a method for increasing the thermal stability of the composition during residence, one or more acid compounds selected from inorganic acids, organic acids and organic acid anhydrides described in JP-A-56-131657 can be used. Method of addition, JP-A-55-12
No. 3647 and Japanese Patent Application Laid-Open No. 54-40854, a method of incorporating an organic phosphonic acid or a phosphoric acid ester metal salt, Japanese Patent Application Laid-Open No. 63-260948, and Japanese Patent Application Laid-Open No. 4-120172. A method of using an organic phosphoric acid ester, an organic phosphorous acid ester, and a metal salt thereof in combination with an organic carboxylic acid or an organic carboxylic acid anhydride, and further, an alkali metal or an alkaline earth metal described in JP-A-6-263962. A method using an ABS resin having a low index and a low chlorine content has been proposed, and some effects have been achieved.

However, the above-mentioned JP-A-6-2639.
In the method described in Japanese Patent No. 62, a large amount of water must be used because it is necessary to thoroughly wash the solidified material in the step of taking out the resin from the ABS latex when manufacturing the ABS resin. Not only was it impossible to save, but the economic burden of wastewater treatment was large.

[0006]

An object of the present invention is to provide a thermoplastic resin composition comprising a polycarbonate resin and a rubber-reinforced resin such as an ABS resin, which is superior in quality to conventional ones and which is superior in retention. It is to obtain a thermoplastic resin composition having excellent thermal stability at the time.

[0007]

Means for Solving the Problems As a result of repeated studies to achieve the above object, the present inventors have found that the pH during coagulation is 6
It was found that the use of the rubber-reinforced resin produced under the conditions of less than and the pH of more than 11 accelerates the hydrolysis of the polycarbonate, and the present invention was completed. That is, the present invention provides a coagulant used in the process of producing a rubber-reinforced resin containing 40 to 95 parts by weight of a polycarbonate resin (A) and a graft copolymer for graft-copolymerizing one or more vinyl compounds with a rubber-like polymer. A thermoplastic resin composition comprising 5 to 60 parts by weight of a rubber-reinforced resin (B), which is an alkaline earth metal salt and is solidified while maintaining the pH in the range of 6 to 11.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail. The polycarbonate resin used in the present invention is preferably produced by reacting a dihydric phenol with phosgene or a carbonic acid diester. As the dihydric phenol, bisphenols are preferable, and 2,2-bis (4-hydroxyphenyl) propane (hereinafter referred to as bisphenol A) is particularly preferable. Further, part or all of bisphenol A may be substituted with another dihydric phenol compound. The dihydric phenol compound other than bisphenol A is, for example, a compound such as hydroquinone, 4,4 dihydroxydiphenyl, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, and bis (4-hydroxyphenyl) ketone. is there. A homopolymer of these dihydric phenols, a copolymer of two or more thereof, or a blend thereof may be used.

The proportion of the polycarbonate component (A) and the rubber-reinforced resin (B) is determined according to the required mechanical strength, rigidity, moldability and heat resistance. The component (A) is preferably 45 to 90% by weight, the component (B) is 55 to 10% by weight, and more preferably the component (A) is 60 to 8%.
5% by weight, and component (B) is 40 to 15% by weight.

The rubber-reinforced resin (B) in the present invention means
The coagulant used in the process of producing a rubber-reinforced resin containing a graft copolymer obtained by graft-copolymerizing one or more vinyl compounds with a rubber-like polymer is an alkaline earth metal salt,
Moreover, it is characterized in that it solidifies while keeping the pH in the range of 6-11.

Any rubbery polymer having a glass transition temperature of 0 ° C. or lower can be used as the rubbery polymer in the present invention. Specifically, dibutadiene rubber such as polybutadiene, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber such as polybutyl acrylate, polyisoprene, polychloroprene, ethylene-propylene rubber, ethylene-propylene- Block copolymers such as diene terpolymer rubbers, styrene-butadiene block copolymer rubbers, styrene-isoprene block copolymer rubbers and hydrogenated products thereof can be used. Among these polymers, polybutadiene, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, polybutyl acrylate and the like are preferable. The proportion of the rubber-like polymer in the rubber-reinforced resin is used in the range of 1% by weight to 95% by weight.
It is determined according to the required mechanical strength, rigidity, and moldability. It is preferably 5 to 80% by weight, more preferably 10 to 75% by weight.

As the vinyl compound to be graft-copolymerized with the rubber-like polymer, there are aromatic vinyl compounds such as styrene, α-methylstyrene and paramethylstyrene, and alkyl (meth) compounds such as methyl methacrylate, methyl acrylate, butyl acrylate and ethyl acrylate. ) Acrylates, (meth) acrylic acids such as acrylic acid and methacrylic acid, vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, and α and β such as maleic anhydride
-Unsaturated carboxylic acid, N-phenylmaleimide, N-methylmaleimide, maleimide-based monomers such as N-cyclohexylmaleimide, and glycidyl group-containing monomers such as glycidylmethacrylate are preferred, but aromatic vinyl compounds are preferred. , Alkyl (meth) acrylates, vinyl cyanide monomers, and maleimide-based monomers, and more preferably styrene, acrylonitrile, N-phenylmaleimide, and butyl acrylate.

These vinyl compounds can be used alone or in combination of two or more. Preferably,
It is a combination of an aromatic vinyl compound and a non-aromatic vinyl compound. In this case, the aromatic vinyl compound and the non-aromatic vinyl compound are used in arbitrary proportions, but the preferable proportion of the non-aromatic vinyl compound is in the range of 5 to 80% by weight.

The ratio of the components grafted to the rubber-like polymer produced during the production of the graft copolymer is measured by dissolving the polymer produced by the polymerization reaction in acetone and separating and removing the insoluble matter with a centrifuge. can do.
The component that dissolves in acetone is the component that has not undergone grafting reaction (non-grafting component) in the copolymer that has undergone polymerization reaction, and the value obtained by subtracting the amount of the rubber-like polymer from the acetone insoluble content is defined as the value of the grafting component. It The proportion of the graft component is preferably 10 to 80 parts by weight, more preferably 2 to 100 parts by weight of the rubber-like polymer.
It is 0 to 60 parts by weight.

The method for producing the above graft copolymer is not particularly limited, but it is an emulsion graft polymerization method in which a vinyl compound is graft-polymerized to a rubber-like polymer latex produced by emulsion polymerization, a continuous method, a batch method, a semi-batch method. Either formula is possible. In the present invention, an emulsion graft method in which a vinyl compound is continuously added to a rubber-like polymer produced by emulsion polymerization together with an initiator, a molecular weight modifier and the like is particularly preferable. The pH at the time of polymerization may be any of alkaline, neutral and acidic conditions, but is preferably neutral or alkaline.

The rubber-reinforced resin (B) of the present invention may contain a component which is produced in the process of producing a graft polymer and which is not grafted to the rubber-like polymer.

The rubber-reinforced resin (B) can be produced by a usual method, for example, by emulsion polymerization to simultaneously prepare a graft polymer and a vinyl copolymer not graft-polymerized, and solidify the rubber-reinforced resin latex with a coagulant. Of the graft polymer and vinyl copolymer (hereinafter referred to as G
(May be abbreviated as RC) latex is prepared, the solid content is coagulated using a coagulant in the same manner as described above, and the solid content is separately compounded with a vinyl copolymer manufactured by bulk polymerization, emulsion polymerization, suspension polymerization, or the like. The desired rubber content can be obtained. The vinyl copolymer in this case is not limited to amorphous or crystalline, but preferably, it contains at least one kind of the aromatic vinyl compound, vinyl cyanide compound, acrylic acid ester and methacrylic acid ester.

The coagulant used in the production process of the rubber-reinforced resin (B) is a salt of alkaline earth metal with sulfuric acid, nitric acid, hydrochloric acid, acetic acid or the like. For example, magnesium sulfate,
Examples thereof include magnesium nitrate, magnesium chloride, magnesium acetate, calcium sulfate, calcium nitrate, calcium chloride, calcium acetate and the like, and calcium chloride is particularly preferable.

In the process of manufacturing the rubber-reinforced resin (B),
The pH for coagulation needs to be adjusted to 6-11. p
When H is less than 6 or pH is more than 11, the hydrolysis of the polycarbonate is promoted and the thermal stability of the resin is lowered. The pH is preferably 7 to 11, particularly preferably 8
10 to 10. The pH at the time of coagulation can be measured by using a general pH measuring device for a supernatant obtained by allowing the coagulated product to settle.

The method of adding the coagulant is not particularly limited. A method in which a high-concentration latex in which a graft copolymer and a vinyl copolymer are produced at the same time is kept at 60 ° C to 80 ° C and an aqueous solution in which an alkali metal salt is dissolved is added to coagulate it, and the latex is stored under a high pressure tank. Put in, 100 ℃ ~ 150 ℃
Method of coagulating by adding the above-mentioned aqueous solution while keeping it warm, and also of adding the above-mentioned atomized aqueous solution to the above-mentioned latex and coagulating it, adding the atomized latex to the above-mentioned aqueous solution. Any method such as addition and solidification is possible. It is also preferable to repeatedly wash the solid content generated by the coagulant.

The thermoplastic resin composition of the present invention includes pigments such as titanium oxide, glass fibers, carbon fibers, fillers and fillers such as mica, antioxidants, stabilizers, antistatic agents, silicone oils, low molecular weights. Lubricants such as polytetrafluoroethylene, mold release agents, phosphoric acid esters, flame retardants such as halogen-containing compounds, flame retardant aids such as antimony trioxide and antimony pentoxide, silicone compounds, high molecular weight polytetrafluoroethylene Anti-dripping agent, dispersant, etc.
Conventional additives such as plasticizers and the like can be included.

The method for producing the thermoplastic resin composition of the present invention is not particularly limited, but a conventional method such as melt blending with a kneader, extruder, Banbury mixer, kneader or the like, solution blending or the like can be used. .

[0023]

The present invention will be described in detail with reference to the following examples. Parts used below are parts by weight. The measuring method in the examples of the present invention is as follows. (Thermal stability) Molding machine (FANUC AS-100
In B), the resin was retained in the cylinder (temperature: 260 ° C.) for 40 minutes, then a molded piece was obtained, and the retention rate of the Izod impact value (the value after retention with the value without retention as 100%) and retention The yellowing degree before and after (ΔYI) was measured. The Izod impact value is measured according to ASTM D256, the thickness of the test piece is 3.2 mm, and the notch is provided. The unit of the numerical value is kg · cm / cm. The tensile test is A
The unit of the numerical value is%, which is a measurement based on STM D638. The yellowing degree is a measurement based on JIS Z8722 (ΔYI was measured by an SM color computer manufactured by Suga Test Instruments Co., Ltd.). Melt flow rate is JIS K
According to the measurement based on 7210, the measurement temperature is 220 ° C. and the load is 10 kg. The unit of the numerical value is g / 10 minutes.

Examples 1 to 3 Polybutadiene rubber latex (CN WOOD Co., Ltd.)
30 parts by weight average particle diameter of 300 nm (measured by MODEL-6000 manufactured by K.K.) were charged with 100 parts of deionized water in a 10 liter reactor, and the gas phase was replaced with nitrogen.
The initial solution was heated to 70 ° C. Next, an aqueous solution (1) having the composition shown below and a monomer mixed solution (2) were continuously added to the reactor for 8 hours for polymerization. After completion of the addition, the temperature was maintained for 1 hour to complete the reaction.

The composition of the aqueous solution (1) is as follows. Ferrous sulfate 0.005 part Sodium formaldehyde sulfoxylate (SFS) 0.1 part Ethylenediaminetetraacetic acid disodium (EDTA) 0.05 part Deionized water 50 parts Monomer mixture (2) has the following composition It is as follows. Acrylonitrile 21 parts Styrene 49 parts t-Dodecyl mercaptan (t-DM) 0.8 parts Cumene hydroperoxide (CHP) 0.1 parts

After the antioxidant was added to the ABS latex thus obtained, 1.0 part of calcium chloride was added to the polymer to coagulate it. The pH during coagulation is
It was 9.5. Further, it was dehydrated, washed with water and then dried to obtain a rubber-reinforced resin (B-1). A polycarbonate resin having a weight average molecular weight of 24,500 was mixed with this at a ratio shown in Table 1, and a 30 mm extruder (PCM-30 manufactured by Ikegai Co., Ltd.) was mixed.
To obtain pellets.

Examples 4 to 6 Pellets were obtained in the same manner as in Examples 1 to 3 except that the weight average molecular weight of polycarbonate in Examples 1 to 3 was 28,600.

Examples 7 to 8 Rubber reinforced resins (B-2) were obtained in the same manner as in Examples 1 to 3 except that the coagulant was magnesium chloride. The pH at the time of coagulation was 7.5. Hereinafter, pellets were obtained in the same manner as in Examples 1 to 3.

Examples 9 to 10 Rubber reinforced resins (B-3) were obtained in the same manner as in Examples 1 to 3 except that the steps of dehydration and washing were repeated 3 times.
The pH at the time of coagulation was 9.5. Hereinafter, pellets were obtained in the same manner as in Examples 1 to 3.

Comparative Examples 1 and 2 A rubber-reinforced resin (C-1) was obtained in the same manner as in Examples 1 to 3 except that sulfuric acid was used as the coagulant. The pH at the time of coagulation was 2.7. Hereinafter, pellets were obtained in the same manner as in Examples 1 to 3.

Comparative Examples 3 to 4 A rubber-reinforced resin (C-2) was obtained in the same manner as in Examples 1 to 3 except that the coagulant was aluminum sulfate. The pH at the time of coagulation was 4.5. Hereinafter, pellets were obtained in the same manner as in Examples 1 to 3.

[0032]

[Table 1]

The coagulants shown in the table are (1) calcium chloride, (2) magnesium chloride, (3) sulfuric acid,
(4) is aluminum sulfate.

[0034]

Since the thermoplastic resin composition of the present invention is excellent in thermal stability, physical properties are not significantly deteriorated during extrusion and molding, and large-sized molded products and thin molded products can be easily obtained. This effect is that in a resin composition comprising a polycarbonate and a rubber reinforced resin, the coagulant used when producing the rubber reinforced resin is an alkaline earth metal salt,
In addition, it can be achieved by using a rubber-reinforced resin characterized by being solidified while keeping the pH in the range of 6 to 11.

Claims (3)

[Claims] 1. Polycarbonate resin (A) 40-95
The coagulant used in the manufacturing process of the rubber-reinforced resin containing parts by weight and a graft copolymer in which one or more vinyl compounds are graft-copolymerized with the rubber-like polymer is an alkaline earth metal salt and has a pH of Rubber-reinforced resin (B) 5-6 characterized by being solidified while maintaining the range of 6-11
A thermoplastic resin composition comprising 0 parts by weight. 2. The thermoplastic resin composition according to claim 1, wherein the alkaline earth metal salt is a salt derived from hydrochloric acid or sulfuric acid and an alkaline earth metal. 3. The thermoplastic resin composition according to claim 1, wherein the alkaline earth metal salt is calcium chloride.