JPS61233044A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain an ABS resin composition having high thermal stability, giving a molded article having excellent surface gloss and containing specific amounts of reaction product of emulsifier and unreacted emulsifier, by mixing a rigid polymer with a graft polymer having high grafting ratio of rubber particles and produced by using a small-sized rubber particles. CONSTITUTION:The objective composition containing <=2% residual emulsifier and reaction product of emulsifier is produced by mixing (A) a graft polymer having a grafting ratio of rubber particles of >=60(wt)% and obtained by the emulsion copolymerization of 50-90% aromatic vinyl monomer, 10-40% vinyl cyanide monomer and if necessary 0-40% copolymerizable vinyl monomer (e.g. methyl methacrylate) in the presence of a diene rubber latex having a number-average particle diameter Dn of <=0.1mu and a ratio of Dw/Dn of >=5 (Dw is weight-average particle diameter) with (B) a rigid polymer produced by the suspension or bulk polymerization of an aromatic vinyl monomer, a vinyl cyanide monomer and if necessary a copolymerizable vinyl monomer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thermoplastic resin composition that is highly thermally stable and has excellent surface gloss of molded products, particularly high-temperature injection molded products.

(Prior art) ABS resin is a resin with excellent balance of physical properties such as mechanical strength, moldability, and surface gloss, and has a wide range of uses including automobile parts, electrical equipment parts, and office equipment parts. However, these applications include those requiring particularly good surface gloss.

It is known that the surface gloss of an ABS resin molded product is strongly influenced by the particle size of the rubber particles contained in the resin, and the smaller the particle size, the higher the surface gloss of the ABS resin obtained. Furthermore, the surface gloss is influenced by the dispersion state of the rubber particles, and the better the dispersion state, the higher the surface gloss of the resulting ABS resin.

By the way, ABS resin containing small particle size rubber has a lower weight than ABS resin containing large particle size rubber of the same weight.
The distance between the rubber particles dispersed in the resin is short, and therefore the rubber particles collide with each other frequently during melt shearing. Therefore, with rubber particles having a low grafting rate, Jl agglomeration of male rubber particles occurs due to collision, which reduces the surface gloss of the molded product, and in severe cases, silver particles appear on the surface of the molded product. The appearance of streaks is observed.

That is, in order to obtain an ABS resin with good surface gloss, it is necessary to use rubber with a small particle diameter and to sufficiently increase the grafting ratio of the rubber particles.

In order to obtain such an ABS resin, the so-called emulsion graft polymerization method is optimal, in which a monomer that becomes a guar branch is subjected to emulsion polymerization in the presence of a rubber latex obtained by emulsion polymerization. However, AB obtained by emulsion graft polymerization
S resins have problems during molding, such as the emulsifier and the reaction product of the emulsifier and the precipitating agent, that is, the emulsifier reaction product remaining in the resin, and poor thermal stability caused by the emulsifier and the emulsifier reaction product. A defective phenomenon is observed.

The reduction in surface gloss of ABS resin is particularly noticeable during high-temperature injection molding, and the phenomenon of poor thermal stability is also remarkable during high-temperature molding. , ABS with good appearance
This imposes a great deal of restriction on the molding conditions for producing resin molded products, and is industrially unfavorable.

In order to produce an ABS resin with a suppressed content of emulsifier reaction products, an ABS resin with a high diene content, produced by emulsion graft polymerization, is produced by suspension polymerization or bulk polymerization. Diene-based ABS with low mu content
A technique of diluting with an As resin that does not contain III fat or diene rubber is known. However, when an ABS resin with a high diene rubber content is produced by emulsion graft polymerization using a small particle diameter rubber, and then this is diluted to produce an ABS resin with a desired rubber content, the obtained The surface gloss of the AB8 resin molded product is low, and in severe cases, silver streaks are observed on the surface of the molded product.

(Problems to be Solved by the Invention) The purpose of the present invention is to simultaneously solve the phenomenon of reduced surface gloss and poor thermal stability observed in ABS resin injection molded products, especially high-temperature injection molded products. It is said that

(Means for Solving the Problems) That is, as a result of intensive studies in view of the above knowledge, the present inventors have discovered that aromatic vinyl monomers and vinyl cyanide monomers can be combined in the presence of diene rubber latex. A graft polymer obtained by emulsion copolymerization of a monomer mixture containing an aromatic vinyl monomer and a hard polymer obtained by copolymerizing a monomer mixture containing an aromatic vinyl monomer and a vinyl cyanide monomer. In a composition obtained by mixing the diene rubber particles contained in the composition, the number average particle diameter Dn of the diene rubber particles is 0.1 μ or less, and the weight average particle diameter Dw of the diene rubber particles and the number average particle Ratio D to diameter Dn
w/Dn is 5.0 or more, the grafting rate of the graft polymer is 60% or more, and the content of the emulsifier and emulsifier reaction product present in the composition is 2% by weight or less. The inventors have discovered that the characteristic thermoplastic resin composition has excellent surface gloss, especially surface gloss during high-temperature injection molding, and is rich in thermal stability during high-temperature molding, leading to the completion of the present invention.

That is, the ABS resin composition of the present invention eliminates the phenomenon of gloss reduction or poor thermal stability caused by high-temperature molding, thereby suppressing the occurrence of molding defects, and this effect is extremely advantageous industrially.

Next, the present invention will be explained in detail.

The diene-based co-9 latex used in the present invention is obtained by emulsion polymerization of a diene-based monomer or a diene-based monomer and other copolymerizable monomers. Other copolymerizable monomers include aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene, t-butylstyrene, acrylonitrile, methacrylate trile, etc. These include vinyl cyanide monomers, and (meth)acrylic acid ester monomers such as methyl methacrylate, ethyl acrylate, and butyl acrylate. Specific examples of diene rubbers suitably used in the present invention include Prittadiene 1. Polyisoprene, poly(butadiene-styrene), poly(ftadiene;/-7crylonitrile), poly(butadiene-methyl methacrylate)
,? (butatsuene-butyl acrylate), etc. These diene rubber latexes may be used alone or in combination.

In the present invention, in the presence of diene rubber latex, an aromatic vinyl monomer, a vinyl cyanide monomer, and, in some cases, a mixture of a vinyl monomer copolymerizable with these are emulsion copolymerized. However, ζSpecific examples of aromatic vinyl monomers mentioned here include styrene, α-methylstyrene,
Examples of vinyl monomers such as vinyl toluene and t-butylstyrene include acrylonitrile and methacrylonitrile. Examples of vinyl monomers that can be copolymerized with these are used as necessary. Examples include methyl methacrylate, ethyl acrylate, and butyl acrylate. Preferred monomer combinations include styrene-7crylonitrile, styrene-α-methylstyrene-acrylonitrile, styrene-methylmethacrylate-acrylonitrile, and α-methylstyrene-acrylonitrile.

In the present invention, the preferable proportions of each monomer to be subjected to emulsion copolymerization in the presence of diene rubber latex are 50 to 90% by weight of aromatic vinyl monomer and 1% by weight of vinyl cyanide monomer.
0-40g amount, other copolymerizable vinyl monomers 0
-40% by weight, particularly suitable conditions include 60-80% by weight of aromatic vinyl monomer and 20-3% by weight of vinyl cyanide monomer.
5% by weight, other copolymerizable vinyl monomers 0-20
It is a percentage by weight. The content of aromatic vinyl monomer is 5
If it is less than 0% by weight, the obtained resin will have poor six-step processability, and if it exceeds 90% by weight, it will have poor mechanical strength, which is not preferable.

In the present invention, the graft ratio of the graft polymer obtained by emulsion copolymerization of monomers in the presence of diene rubber latex is
It needs to be 60% or more. Here, the graft ratio is ([graft branch weight]/[diene system weight])
X 100 blunt). An ABS resin made of a graft polymer with a graft ratio of less than 60%,
During high-temperature injection molding, a phenomenon in which gloss decreases due to agglomeration of plum particles is noticeable, which is undesirable.

Cal is the emulsifier used in emulsion polymerization and emulsion graft polymerization of diene rubber. Preferably, it is a phosphate salt.

Cal mentioned here? Phosphates are higher fatty acid salts, resinates, etc. Specific examples of higher fatty acid salts include caprylates, caprates, diurates, mystiphosphates, palmitates, and stearates. Specific examples of salts, oleate, linoleate, lylunate, etc., and resinates include abietate and the like. However, both higher fatty acid salts and resin acid salts are often prepared as mixtures of many different compounds, and the specific examples given above should be understood as being one component in the mixture. Further, the cations of the calcium salt type emulsifier are alkali metal ions, ammonium ions, etc.), and specific examples of the alkali metal ions include potassium ions, sodium ions, lithium ions, etc.

The graft polymer latex is recovered through a precipitation operation in which a precipitation agent is added to precipitate the latex, but there are no particular restrictions on the precipitation operation, and known techniques can be applied.

Acids and/or water-soluble salts are effectively used as precipitating agents. Specific examples of acids include hydrochloric acid, sulfuric acid, phosphoric acid, and acetic acid, and specific examples of water-soluble salts include sodium chloride and ammonium chloride. , calcium chloride, magnesium chloride, barium chloride, aluminum chloride, sodium sulfate, magnesium sulfate, aluminum sulfate, ammonium aluminum sulfate, potassium aluminum sulfate, sodium aluminum sulfate, etc.

In the present invention, a hard polymer which is a copolymer of an aromatic vinyl monomer and a vinyl cyanide monomer, or a copolymer of both types of these monomers and a vinyl monomer copolymerizable with them is used. However, specific examples of aromatic vinyl monomers mentioned here include styrene, α-methylstyrene, vinyltoluene, t-butylstyrene, etc., and specific examples of vinyl cyanide monomers include acrylonitrile, methacrylate, etc. Specific examples of vinyl monomers copolymerizable with these include methyl methacrylate, ethyl acrylate, butyl acrylate, and the like. Examples of preferred monomer combinations include styrene-acrylonitrile, styrene-α-methylstyrene-acrylonitrile, styrene-methylmethacrylate-acrylonitrile, and α-methylstyrene-acrylonitrile.

One of the features of the present invention is to reduce the content of emulsifier reaction products and unreacted residual emulsifiers, which are reaction products between the emulsifier used in the emulsion polymerization process and the precipitation agent added in the emulsion polymerization latex precipitation process. It is to stipulate. That is, the total amount of the emulsifier and the emulsifier reaction product contained in the resin composition obtained by mixing the graft polymer and the hard polymer is 2% by weight or less, preferably 1.5% by weight or less, more preferably 1.5% by weight or less. It is necessary that the I/'i1x amount be less than or equal to the amount of I/'i1x. If the content of the emulsifier and its reaction product in the ABS resin composition exceeds 2% by weight, the thermal stability during high-temperature molding will be poor, which is undesirable.

In order to keep the emulsifier reaction product content in the ABS resin composition to 2% by weight or less, fc adopts suspension polymerization or bulk polymerization for the polymerization of the hard polymer, and removes the diene contained in the emulsion graft polymer. It is preferable to increase the rubber content (rubber ratio). When the comb ratio of the graft polymer is increased, the proportion of the graft polymer in the obtained ABS resin composition decreases, and the amount of the emulsifier reaction product mixed in can be suppressed to a low level. Here, the comb ratio of the graft polymer is 4
The content is preferably 0 to 62% by weight, and if it is less than 40% by weight, it will be difficult to suppress the content of the emulsifier reaction product contained in the ABS resin composition to 2% by weight or less. If it exceeds 62% by weight, it is difficult to achieve a grafting ratio of 60% or more, resulting in a decrease in gloss.

In order to make the rubber ratio of the graft polymer 40 to 62 times iL and the graft ratio 60% or more, it is preferable to select an initiator for graft polymerization, such as cumene hydrono mother oxide, di-isopropylene Gilpenzenhydronoya-oxide, penzoylnog-oxide, G-t
It is possible to use initiators such as -butyl/-P-oxide, dicumyl peroxide, 1-butyl deroctate, but especially t-butylhydrono! -OxyP1 t-butylcumyl peroxide, t-butylno'! ? -oxyacetate, -butylperoxybenzoate, t-butylno-4-oxyisoglopyrucar? Nate and the like are preferably used.

The diene rubber particles contained in the composition of the present invention have a number average particle diameter Dn of 0.1 μ or less, and a weight average particle diameter DW
It is necessary that the ratio Dw/Dn of the particle size and the number average particle diameter Dn be 5.0 or more, preferably 7.0 or more.

The average particle diameter can be determined by taking a transmission electron microscope photograph of the obtained ABS resin, and determining the fraction f1 of particles with a particle diameter di from the photograph.
Find Dn=(rf tdi )/r:f,, Dw=
(Σt1a1')/Cx:riai'').

If the number average particle diameter Dn of the diene rubber particles exceeds 0.1μ, the resulting ABS resin composition will have poor gloss and Dv
When i/D n is less than 5°0, the obtained ABS
The impact resistance of the resin composition is unfavorable.

Diene rubber is produced by emulsion polymerization, but there are no particular restrictions on the method of controlling the particle size distribution of diene rubber within the range specified in the present invention. For example, after diene rubber latex obtained by emulsion polymerization, As a method applied to the treatment process, a method of supplying diene rubber latex to a ball-flow device and enlarging it under pressure (Japanese Patent Publication No. 41-982, Japanese Patent Publication No. 41-1982)
8-4458, etc.), a method of adding acid and/or water-soluble salt to diene rubber latex to coagulate and enlarge it (Japanese Patent Publication No. 39-8390, Japanese Patent Publication No. 42-3112, etc.), I-rivinyl alcohol, polyethylene glycol-polypropylene glycol block:
Examples include a method of adding a water-soluble polymer substance such as yyt reamer and dimethyl cellulose, a method of adding an organic solvent to the latex, a method of lowering the temperature of the latex, etc. Methods to be applied during emulsion polymerization include seeding polymerization method (Japanese Patent Publication No. 49-39194, etc.), method of controlling latex m degree during polymerization [Japanese Patent Publication No. 48-16060]
Examples include, but are not limited to, the following.

The composition of the present invention may contain antioxidants, weathering agents,
Antistatic agents, plasticizers, colorants, lubricants, fillers, reinforcing materials, etc. can be added.

(Example) The present invention will be further explained below with reference to Examples, and all parts and parts described in Examples and Comparative Examples are expressed on a weight basis.

Reference Example 1 - Production of Polybutadiene Rubber Latex A ~ In a stainless steel autoclave, 2.0 parts of potassium stearate, 0.1 part of potassium persulfate, and 0 parts of sodium acetate were placed in a stainless steel autoclave.
．． Add 200 parts of pure water in which 2 parts of divinylbenzene was dissolved, and add 0.08 parts of divinylbenzene and 4゜47-butyrizo/bis-6-
71 parts of t-butyl metacresol O was added. Next, 100 parts of tutadiene was pressurized and stirred at 65° C. for 30 hours to carry out polymerization.

After 30 hours, unreacted butadiene was removed to obtain polybutanoene rubber latex. The weight average particle diameter of the obtained latex was 0.06μ.

In addition, the weight average particle diameter is determined by using a tin latex with a known weight average particle diameter, creating a calibration curve by determining the relationship between the absorbance and the weight average particle diameter, and using this curve,
It was determined by measuring absorbance.

Then, the Muratex was supplied to a model 15M8TEA homogenizer manufactured by Manton-Gaulin, USA;
56 kg/am" to obtain ?ligtadiene rubber latex A-1.

Reference Example 2 - Polyptazoene rubber latex J~L! !
! Polyoxyethylene-I lyoxygcobylene-block copolymer (polypropylene glycol molecule 1
-2250, 40% of ethylene oxide in the total molecule) was added in an amount of 1.5 parts per 100 parts of polybutanoene. While stirring the latex under high shear, an aqueous solution of 5% acetic acid was added to adjust the pH of the latex to 6.5. Then, a potassium hydroxide solution was added to bring the pH of the latex to 11.
As,? Liptadiene rubber latex J-L was obtained.

Reference Example 3 - Production of Styrene-Tadiene Copolymer (SBR Gam) Latex M 5 parts (as solid content) of the rubber latex with a weight average particle diameter of 0.06μ obtained in Reference Example 1
into an autoclave, and further add 200 parts of pure water, 0.85 il of potassium stearate, and 0.2 divinylbenzene.
m, 0.15 parts of t-F decyl mercaptan, 0.2 parts of potassium persulfate, and 24 parts of styrene were added.

71 parts of putazoene was introduced under pressure, and the mixture was heated at 60°C for 15 hours.
The polymerization was completed by stirring at 0° C. for 10 hours.

The Xtt average particle diameter of the obtained latex was 0.17μ.

Example 1 A stainless steel autoclave was charged with 357 parts of polybutanoene rubber latex A (solid content 28%), followed by 210 parts of pure water, 0.005 parts of ferrous sulfate, 0.01 parts of western sodium ethylenediaminetetraacetate, 0.3 part of sodium formaldehyde sulfoxylate was added, and the mixture was stirred under a nitrogen atmosphere. The contents were kept at 60°C, and 25 parts of acrylonitrile, 75 parts of styrene, 0.6 parts of tyr silmercaptan, and 1.5 parts of the polymerization initiator shown in Table 1 were added.
A monomer mixture consisting of 100 parts of m01e/monomer mixture was continuously added to the latex over a period of 5 hours.

After the addition of the monomer mixture was completed, the polymerization initiator shown in Table 1 was added at 0.5 mm0/100 parts of the monomer mixture,
The mixture was further stirred at 70° C. for 2 hours to complete the polymerization.

An aqueous solution containing 8 parts of calcium chloride was added to the obtained latex, and the mixture was stirred at 95° C. for 3 minutes to obtain a precipitate. This precipitate was dehydrated, washed with water, and dried to obtain ABS resin powder.

40 parts of this resin powder was mixed into an acrylonitrile-styrene suspension copolymer (As resin/acrylonitrile content 27%).
60 parts of 2.6-di-t-butyl-4-methylphenol, 0.1 part of triphenyl 7-osphite, and 2.0 parts of ethylene bisstearylamide were mixed together and fed to an extruder to form pellets. Obtained.

A test piece was prepared from this pellet, and its physical properties were measured. The results are shown in Table 1.

Incidentally, the measured values of the Examples and Comparative Examples described below were all obtained by the following method.

Izot impact strength: ASTM D-256 Melt 70-i7f')x: ASTM D-1238, temperature 250°C, load 5# Glossy knee e-let manufactured by Toshiba Machine Co., Ltd. IS-12
5 Injection molded by injection molding machine, 100X350X21
A flat molded product of section M is created. The molding temperature is 220°C and 280°C. The gloss value of the obtained molded product is measured at an incident angle of 60 degrees using a digital variable angle gloss meter model UGV-4D manufactured by Suga Test Instruments Co., Ltd. Gloss measurement is performed at five locations avoiding the gate area, and the average value is taken as the gloss value.

Thermal stability: Pellets manufactured by Toshiba Machine Co., Ltd. l5-125
Injection molded using an injection molding machine, 90x50x2.5mm
Create a flat molded product.

The molding temperature is 220°C and 280°C, and for the 280°C molded product, the molten resin is retained in the cylinder for 15 minutes and then injection molded, and the third shot is taken and used as a sample.

The color difference between the 220°C molded product and the 280°C/15 minute retention molded product was measured using C0LORAND C0L manufactured by Nippon Denshoku Kogyo Co., Ltd.
OR'I) IFFERENCE METERMODEL
ND-101DC). A resin with a large color difference measurement value is undesirable for practical use because of its large discoloration due to thermal history.

Grafting rate: After adding the pellet to methyl ethyl ketone and shaking thoroughly, centrifuge to separate insoluble matter. The polybutadiene content in the insoluble matter is determined by the iodine addition method, and the digrafting rate is determined by ([100-(-liptadiene content)]/(polybutadiene content)) x 100 (%).

The insoluble matter for measuring the emulsifier reaction product content and niger raft rate was incinerated and calcium was quantified using an AA646 atomic absorption spectrophotometer manufactured by Shimadzu Corporation, and the measured value was multiplied by 606,740 to determine the amount of calcium stearate in the insoluble matter. shall be. The obtained value is corrected by the insoluble matter content in the AB8 resin composition, and the amount of calcium stearate in the AB8 resin composition is determined. In the present invention, potassium stearate is used as an emulsifier, calcium chloride is used as a precipitating agent, and the emulsifier reaction product is calcium stearate.

Rubber particle size: ABS resin composition pellets were fixed to a jig and surface polished using a JUN-7 type ultramicrotome manufactured by JEOL Ltd. Polishing s04 The sample was immersed in an aqueous solution of 1-osmium tetroxide (41 items) and left at 23° C. for 12 hours to dye the rubber particles. A thin section was prepared from the stained sample using a microtome, and a 4km photograph of the thin section was taken using a JEM-1008 transmission electron microscope manufactured by JEOL Ltd. Develop and enlarge the photograph so that the magnification is 25,000 times, and rubber particle diameter d1
and its fraction fi was measured. The measurement field of view is 67 μ2. Dn=(2'f 1dl)/Ef・, Dw=(L:
r d')/(J t 1.1.3), several l l 1 average particle diameter and weight average particle diameter were determined.

Example 2 100 parts each of polybutadiene rubber latex B to F with different particle sizes were placed in a stainless steel autoclave (
(in terms of solid content), then pure water in an amount such that the solid content after polymerization is 30%, and 0.0% ferrous sulfate. 5 parts of OO, 0.01 part of tetrasodium ethylenediaminetetraacetate, 0.3 part of sodium formaldehyde sulfoxylate)10.
t. Stirred under nitrogen atmosphere. The contents were kept at 60°C, and a monomer mixture consisting of 25 parts of acrylonitrile, 75 parts of styrene, 0.6 parts of t-dodecylmercaptan, and 0.2 parts of t-butylperoxyacetate was added to the latex over 5 hours. Added continuously. After the addition of the monomer mixture was completed, 0.07 part of 1-butylno-4-oxyacetate was added, and the mixture was further stirred at 70° C. for 2 hours to complete the polymerization.

The obtained latex was post-treated in the same manner as in Example 1 to obtain AB
S resin powder was obtained.

This resin powder was blended in the same manner as in Example 1 and fed to an extruder to obtain pellets.

A test piece was prepared from this pellet and its physical properties were evaluated and the results are shown in Table 2.

Comparative Example 1 Pellets were obtained in the same manner as in Example 1 except for using the polymerization initiator shown in Table 3.

A test piece was prepared from this pellet and its physical properties were evaluated and the results are shown in Table 3.

Despite using the same rubber latex as Experiments 1 to 5 in Experiments 11 to 14, D n % D
Both vr/D n are significantly different. This is an experiment! In the ABS resin compositions of Nos. 111 to 14,
This is due to the remarkable agglomeration and enlargement of rubber particles. The remarkable agglomeration phenomenon of rubber particles observed in the ABS resin compositions of Experiments Nos. 11 to 14 is considered to be caused by the low grafting ratio. The reason why the gloss value, especially the gloss value of the 280° C. molded product is low, is considered to be related to the aggregation of the rubber particles. By the way, when we measured the number of rubber particles in the test piece cut out from the molded product for gloss measurement, we found that the number of rubber particles was 22.
50.2 pieces/μ for 0°C molded product, 280°C for experiment delay 2
In the molded product, it was 49.2 pieces/μ2, whereas in the experiment
2 220℃ molded product 23.9 pieces/μz1 Experimental collection 12
In the molded product at 280° C., it was 15°9 particles/μ2, and it can be seen that the agglomeration of rubber particles was significant in the 12 molded products used for the experiment.

Example 3 and Comparative Example 2 Polybutadiene rubber latex A1 used in Example 1
18 parts (solid content: 28 g) were placed in a stainless steel autoclave, followed by 225 parts of pure water and 0.005 parts of ferrous sulfate.
parts, 0.01 parts of tetrasodium ethylenediaminetetraacetate,
0.3 parts of sodium formaldehyde sulfoxylate and potassium stearate were added in the amounts shown in Table 4, and the mixture was stirred under a nitrogen atmosphere. The contents were kept at 60°C, and 25 parts of acrylonitrile, 75 parts of styrene, 094 parts of -dodecylmercaptaf, and 0 t-butyl peroxyacetate were added.
．． A 2 part monomer mixture was continuously added into the latex over a period of 5 hours. After the addition of the monomer mixture, t
-0.07 part of butyl peroxyacetate was added, and the mixture was further stirred at 70°C for 2 hours to complete the polymerization.

The obtained latex was post-treated in the same manner as in Example 1 to obtain AB
S resin powder was obtained.

80 parts of this resin powder, 20 parts of As resin, 2°6-Gt
0.1 part of -butyl-4-methylphenol, 0.1 part of triphenyl 7-osphite, and 2.0 parts of ethylene bisstearylamide were blended and fed to an extruder to obtain pellets.

A test piece was prepared from this pellet and the physical properties were evaluated, and the results are shown in Table 4.

It can be seen that when the content of the emulsifier reaction product deviates from the range of the present invention, the thermal stability is poor.

Example 4 and Comparative Example 3 Polybutadiene rubber latex A3 used in Example 1
57 parts (solid content 28%) was charged into a stainless steel autoclave, followed by 210 parts of pure water and 0.005 parts of ferrous sulfate.
parts, 0.01 parts of tetrasodium ethylenediaminetetraacetate,
0.3 parts of sodium formaldehyde sulfoxylate and 1.5 parts of potassium stearate were added, and the mixture was stirred under a nitrogen atmosphere. The contents were kept at 60°C, and a monomer mixture consisting of 25 parts of acrylonitrile, 75 parts of styrene, 0.4 parts of t-dodecyl mercap, and the polymerization initiator shown in Table 5 was added to the latex over 5 hours. was added continuously. After the addition of the monomer mixture was completed, 0.07 part of azobisimpteronitrile was added, and the mixture was further stirred at 70° C. for 2 hours to complete the polymerization.

The obtained latex was post-treated in the same manner as in Example 1 to obtain AB
S resin powder was obtained.

40 parts of this resin powder, 60 parts of AS resin, 2°6-Gt
-Butyl-4-methylphenol 0.1111S, triphenyl 7-osphite 0.1 part, and ethylene bisstearylamide 2.0 parts were blended and fed to an extruder to obtain pellets.

A test piece was prepared from this pellet, and the physical properties were evaluated and shown in Table 5.

Comparative Example 4 Pellets were obtained in the same manner as in Example 2, except that m of the polybutadiene rubber latex was replaced with B to F and G to ■ were used.

A test piece was prepared from this pellet, and the physical properties were evaluated and the results are shown in Table 6.

In experimental pigeon 22, the number average particle size of rubber particles was

is within the scope of the present invention, but DW/Dn is less than 5.0 and the impact strength is poor. Also, experiment 1'l & 123.2
In No. 4, the Dn exceeds 0.1 μ, so the gloss is poor.

Example 5 and Comparative Example 5 Pellets were obtained in the same manner as in Example 2, except that the type of polytutadiene rubber latex was changed from B to F and JL was used.

A test piece was prepared from this pellet and its physical properties were evaluated and the results are shown in Table 7.

Example 6 A stainless steel autoclave was charged with 60 parts (as solid content) of 1-liptadiene 7mm latex A and 40 parts (as solid content) of SBR rubber latex M, and then the solid content after polymerization was 30%. amount of pure water, 0.005 parts of ferrous sulfate, 0.005 parts of ethylenediamine and sodium acetate
．． 0.01 part of sodium formaldehyde sulfoxylate and 0.3 part of sodium formaldehyde sulfoxylate were added, and the mixture was stirred under a nitrogen atmosphere. The contents were kept at 60°C, and 25 parts of acrylonitrile and 7 parts of styrene were added.
A monomer mixture consisting of 5 parts of t-d-r-silmercaptan, 0.6 parts of t-butylperoxyacetate, and 0.2 parts of t-butylperoxyacetate was continuously added to the latex over a period of 5 hours. After the addition of the monomer mixture was completed, 0.07 part of t-butyl peroxyacetate was added, and the mixture was further stirred at 70°C for 2 hours to complete the polymerization.

The obtained latex was post-treated in the same manner as in Example 1 to obtain AB
S resin powder was obtained.

This resin powder was blended in the same manner as in Example 1 and fed to an extruder to obtain pellets.

A test piece was prepared from this pellet and its physical properties were evaluated. As a result, the Izod impact strength was 29 kf/am/am.

Melt flow index 18g ZlO, gloss 220
°C 92%, gloss 280 °C 89%, thermal stability 4.0, graph 14881 emulsifier reaction product 0.52 cm, number average particle diameter D n of rubber particles 0.0894 μ, Dw of rubber particles
r/Dn was 9.13.

Example 7 and Comparative Example 6 30 parts of the ABS resin powder obtained in Example 2 and Comparative Example 4 was mixed with acrylonitrile-α-methylstyrene suspension copolymer (acrylonitrile content 30%, methyl ethyl ketone 1%, temperature 23°C). Relative viscosity of 1.61) 70 parts, 2,
0.1 part of 6-sheet t-butyl-4-methylphenol,
It was mixed with 0.11 parts of triphenylphosphite to obtain pellets.

A test piece was prepared from this pellet, and the physical properties were measured and the results are shown in Table 8.

(Effects of the Invention) As explained above, in the ABS resin composition of the present invention, the number average particle diameter and the weight average particle diameter of the rubber particles contained are specified, and in particular, the number average particle diameter is set to 0.1μ or less. By specifying this, it is possible to obtain a composition with a high gloss on the surface of a molded article, especially a molded article obtained by injection molding at a high temperature.

Next, the second essential requirement of the present invention is the regulation of the grafting rate. Even if the number average particle diameter of the rubber particles is specified to be 0.1 μm or less, if the grafting rate is less than 60%, a high gloss value cannot be expected from the molded product.

Furthermore, by regulating the content of the emulsifier reaction product contained in the composition to 2 weight or less, a composition having good thermal stability during high-temperature molding can be obtained.

That is, the effect of the present invention is that the molded product obtained by injection molding at high temperature has a high gloss value and good thermal stability.

Claims (1)

[Claims] A graft polymer obtained by emulsion copolymerization of a monomer mixture containing an aromatic vinyl monomer and a cyanated vinyl monomer in the presence of a diene rubber latex, and an aromatic vinyl monomer and a cyanated vinyl monomer. In a composition obtained by mixing a monomer mixture containing a vinyl monomer with a hard polymer obtained by copolymerizing, the number average particle diameter Dn of the diene rubber particles contained in the composition is 0. 1 μ or less, and the ratio Dw/ of the weight average particle diameter Dw and the number average particle diameter Dn of the diene rubber particles.
Dn is 5.0 or more, the grafting rate of the graft polymer is 60% or more, and the content of the emulsifier and emulsifier reaction product present in the composition is 2% by weight or less. thermoplastic resin composition.