JPS6155143A - Impact-resistant thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide a resin compsn. having excellent impact resistance, by mixing a copolymer obtd. by grafting an arom. vinyl monomer and an unsaturated nitrile onto a diene rubber with a copolymer composed of an arom. vinyl monomer and an unsaturated nitrile. CONSTITUTION:An arom. vinyl monomer and an unsaturated nitrile monomer are copolymerized in the presence of a diene rubber to prepare a copolymer (A) composed of 20-95wt% gel particles having an average particle size of 0.1- 0.4mum and 80-5wt% gel particles having an average particle size of 0.4-1mum. The copolymer (A) is mixed with a copolymer (B) composed of a residue of an arom. vinyl monomer and a residue of an unsaturated nitrile monomer in such a proportion that the compsn. has a diene rubber content of 10-30wt% and a difference in content between the residue of the unsaturated nitrile monomer in the graft chain of the copolymer (A) and the residue of the unsaturated nitrile monomer in the copolymer (B) is within 1wt%, thus obtaining the titled resin compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a thermoplastic resin composition having excellent impact resistance.

"Prior art" A method in which rubber is graft-polymerized with an aromatic vinyl monomer such as styrene or an unsaturated nitrile monomer such as acrylonitrile.
Rubber-modified styrenic resins such as BS resin and high-impact polystyrene have a good balance of impact resistance and moldability, and are therefore widely used in electrical appliance casings, automobile parts, and the like. For these resins, especially ABS resins.

Rubber content, glue particle size distribution, and composition of grafted chains.

It is known that impact resistance is affected by the surface conditions of glue particles such as molecular weight and grafting ratio, and many improvements have been made (for example,
No. Publication, Special Publication Shojter, Y, RSR Publication, etc.).

``Problems to be solved by the invention'' However, for the purpose of reducing the amount of resin used by improving impact resistance, improving moldability and improving moldability, etc. Further improvements were needed.

"Means for Solving the Problems" As a result of intensive research aimed at obtaining an ABS resin composition with excellent impact resistance, the present inventors discovered that graft chains and matrix (continuous phase) resin 9. Adjusting the content of unsaturated nitrile monomer residues within a specific range. It has been discovered that the above objectives can be achieved.

In other words, the above-mentioned object of the present invention is to produce a copolymer (AJ, A copolymer (B) containing an aromatic vinyl monomer IA group and an unsaturated nitrile monomer residue], an impact-resistant thermoplastic resin composition having a diene rubber content of 10 to 30% by weight. In products, copolymers (gel particles in Al have an average particle size of 0.1-Q, ψμm20-9j
M'! Jk%, and the average particle size is 0. μ to 7 μm, the content of unsaturated nitrile monomer residues in the graft chain of the copolymer (A) and the unsaturated nitrile monomer in the copolymer fEl are Difference in mer residue content is /1
18; achieved by a composition characterized in that it is within r%.

The diene rubber used in the present invention is butadiene, isoprene, /,! It contains at least 50% by weight of conjugated diene monomer residues such as penmediene and ionprene. Specifically, polybutadiene, polyimprene,
Neoprene, styrene-megen copolymer, etc. are used.

Examples of aromatic vinyl monomers include styrene, α-methylstyrene, □-methylstyrene, 0-methylstyrene, m
-Methylstyrene, 18buty-probylstyrene s' t
Art-butylstyrene, vinylnaphthalene, etc. are used. As the unsaturated nitrile monomer, acryl-α-nitrile, methacronitrile, etc. are used.

Copolymer (Shu) is produced by polymerizing an aromatic vinyl monomer and an unsaturated nitrile monomer in the presence of a diene rubber.11 Polymerization methods include bulk polymerization, suspension polymerization, and bulk-suspension. Although polymerization or the like may be used, emulsion polymerization is most preferable.

The gel particles in the copolymer fAl have a bimodal distribution and have an average particle size of 0. /~0. Gel particles with a small particle size of 20~μm! Weight i%5 and average particle size O0μ~/μm
It consists of 10 to 14 pieces of large-sized gel particles. In this specification'DIC, gel particles refer to copolymer particles in which graft chains consisting of aromatic vinyl monomer residues and unsaturated nitrile monomer residues are formed on rubber molecules. As described later, the copolymer obtained by polymerizing aromatic vinyl monomers etc. in the presence of rubber includes a portion grafted onto the rubber and a portion not grafted onto the rubber. When mixed with a solvent such as methyl ethyl ketone,
The former does not dissolve but disperses, while the latter dissolves and becomes a solution.

The former correspond to gel particles. In addition, in the present invention, the average particle diameter of gel particles is a value measured using a particle size measuring device "Nanosizerco" manufactured by Colemay, USA.

By setting the particle size distribution of the gel particles to have a bimodal distribution as described above, the impact resistance of the composition can be improved.

If the particle size of the large gel particles is less than 0 μm, the impact resistance will not be improved, and if it exceeds 1 μm, coagulation will occur and the appearance of the composition will deteriorate, which is not preferable. Moreover, the average particle diameter of the small particle size gel particles is 0. If it is less than /pm, the impact resistance will decrease, and if it exceeds o3 μm, the appearance of the composition will deteriorate, which is not preferable. Furthermore, if the small-sized gel particles are contained in an amount exceeding 20% by weight, the impact resistance of the composition decreases, and the impact resistance of the composition decreases.
If the content of large gel particles exceeds 10% by weight, the appearance of the m-acid will deteriorate and is therefore not preferred.

When producing a copolymer by an emulsion polymerization method, the particle size of the glue is preferably adjusted by subjecting the raw rubber latex to various particle size enlargement operations.

That is, the diene rubber latex obtained by emulsion polymerization of butadiene etc. has an average particle size of Q,/μm or less, θ,
θ! H, PO4, H, 804, ]
It is preferable to add an acidic substance such as HaaooFL to the latex to weaken the effect of the emulsifier, and to preliminarily coagulate and enlarge the rubber latex particles prior to graft polymerization. When rubber particles in latex are agglomerated and enlarged to a large particle size in order to obtain large gel particles, acid anhydrides such as acetic anhydride, NaOl, KOJ, Na
Using salts such as 2B04, the temperature of the latex is gradually lowered to prevent sudden partial aggregation of latex particles. The particles contain H3PO4,
Obtained by adding acids such as 0HaOOOH and [2B04.

The dog and /JS particle size rubber latex obtained with this =9 were mixed in a predetermined ratio.

Subsequently, predetermined amounts of an aromatic vinyl monomer and an unsaturated nitrile monomer, and if necessary, an emulsifier, a voice modifier, etc. are added, and emulsion polymerization is carried out. The ratio of the aromatic vinyl monomer and the unsaturated nitrile monomer is such that 20 to 3j% by weight of the total monomer residues in the graft chain of the graft copolymer (A) is the unsaturated nitrile monomer. It is preferable to adjust it so that it becomes a residue. In general, as the content of unsaturated nitrile monomer residues decreases, chemical resistance, impact resistance, etc. tend to decrease).
If it increases, the fluidity and color tone of the composition during melting tend to deteriorate, so the above range is desirable. During polymerization, the ratio of rubber to the total amount of monomer mixture and rubber is 70
~? It is preferable to contain 01 ft% to 1,20 to SO
It is preferable to contain it by weight. If it is less than 10 wt'Ik%, the rubber content in one composition cannot be adjusted to v4, and 10
Exceeding this percentage by weight is not preferable because post-treatment becomes difficult. Copolymer (in the production of Shu, water-soluble peroxides such as potassium persulfate and ammonium persulfate are used as initiators,
It is preferable to use a ludox-based initiator or the like. Furthermore, chain transfer agents such as terpenes and mercaptans, and other auxiliary agents may be used as necessary. For the post-treatment of the copolymer (A), conventional emulsion polymerization post-treatments, such as salting out, dehydration, and drying, are applied.

The polymer obtained by the above polymerization method is usually a copolymer consisting of an aromatic vinyl monomer residue and an unsaturated nitrile monomer residue grafted to a diene rubber molecule, that is, a copolymer (Al, A copolymer consisting of aromatic vinyl monomer residues and unsaturated vinyl monomer residues that are not grafted to rubber molecules, ie, a copolymer (Bl).

Therefore, if a composition having a desired rubber content has already been obtained by the above polymerization method, the copolymer (Bl
does not need to be added separately. However, when the rubber content of the composition is high, in order to adjust the rubber content in the composition to a desired range, a copolymer obtained by separate polymerization (
Preferably, Bl is added. The method for producing the copolymer (B) is not particularly limited; 1 Usually, an aromatic vinyl monomer and an unsaturated nitrile monomer are copolymerized by a continuous bulk polymerization method, a bulk-suspension polymerization method, etc. and manufacture it.

The content of unsaturated nitrile monomer residues in the copolymer (B) and the unsaturated nitrile monomer residue contained in the graft chain of the copolymer (A). j! The content of Japanese nitrile may be greater than the other, but it is necessary that the difference be within /i% by weight, preferably within 0, j% by weight. If the difference in the content of the graft chains of the copolymer (F) and the unsaturated nitrile monomer residue contained in the copolymer (E) exceeds 1% by weight, the impact resistance of the resulting composition and other This is undesirable because improvements in various physical properties cannot be achieved.

The content of unsaturated nitrile monomer residues in the graft chains of the copolymer (Shu) was measured in the following manner. That is, impact-resistant thermoplastic resin composition 6f according to the present invention was mixed with acetone 20
After dispersing and stirring in Ortd, centrifugation is performed to remove the insoluble portion, ie.

The copolymer (AJ was separated. The separated insoluble part was dissolved in 2 oorxl of chloroform, and then 10 w of methanol was added.
After adding t1 and ethyl acetate io-, osine degradation was performed to separate the graft chain portion. After the ozonolysis was completed, the solution was concentrated to 20w1, methanol was added thereto, and the copolymer (Shu) graft chain portion was reprecipitated and separated. After drying the obtained graft chain portion under reduced pressure, elemental analysis was performed. Cut it.

The content (% by weight) of unsaturated nitrile monomer residues was determined.

Further, the content of unsaturated nitrile monomer residues in copolymer (B) was determined by elemental analysis of the polymer obtained by concentrating the acetone-soluble portion and reprecipitating with methanol.

Of course, in order to use the composition according to the invention as a molding material, stabilizers, colorants and lubricants are required.

Various additives such as fillers can be blended.

"Effects of the present invention" The composition according to the present invention has excellent mechanical properties such as isot impact strength, falling weight impact strength [(?DI), tensile strength, and elongation, and has high melting fluidity. Since it has excellent moldability and has good moldability, it can be used in the manufacture of electrical appliance casings, automobile parts, etc., and has high industrial utility value.

"Example" The present invention will be described in more detail based on Examples and Comparative Examples.

Examples/~B, Comparative Examples/-j" [Manufacture of rubber latex] In a reactor with a capacity of fz3oofl, which has a stirring device, a heating and cooling device, and raw material addition piping, higher fatty acid sodium 3. Kokaku potassium chloride was added.
jlOk? 2j% Na0E [K5 Yo Misaki Styrene /, 7 # t-dodecyl mercaptan ztH butadiene 68 + 2 potassium persulfate
lkorkg deionized water
109Jd2 was charged and reacted at 7°C.

During the polymerization, from the 1st hour to the jth hour), the mixture was poured into the reactor.

Styrene t,r # t-dodecylmercaptan 20/Akl
Continuously add 682kl of butadiene,
After continuing the reaction for 6 hours, the temperature was raised from ≦7℃ to 10℃ over 1.5 hours, and then for another 2 hours and 30 minutes! After continuing the reaction at θ°C, the reaction was completed by cooling. The resulting latex has a solid content 32. Weight: pH/2 Particle size: 0.07 μm Gel content: 0%. Hereinafter, this latex will be referred to as latex l.

[Manufacture of non-particle size rubber latex]

The latex/
/7. jμ綽μr alkyl diphenyl ether disulfonic acid 2
6. j? deionized water io,
sirg was prepared, and at S5°C, an aqueous phosphoric acid solution with a concentration of j% by weight was continuously added, and 1 minute had passed after the addition was completed.

10% by weight water-defeated potassium trv
-Y Hiro by weight% Alkino Daenyl Ete Tsune θhon 9
7-da 7jf deionized water
Added jot.

This latex Average particle diameter O, koyoμm Solid content: λ3.4 pH7,s I failed.

[Manufacture of large particle size rubber latex]

The latex/container is placed in a capacity Hong On reactor that has a stirring device, heating and cooling device, and raw material addition piping.
/7. J Hiro 4 deionized water μ, 0
The cod was added and 1100 t of acetic anhydride/Q7 f deionized water was mixed and added at 25°C. This acetic anhydride solution and Latenx 1 were stirred for about 7 minutes so that they were uniformly mixed, and then,
Leave to stand without stirring, and after 30 minutes at weight % sodium alkyl diphenyl ether disulfonate 2/9F deionized water
After 60 minutes, #)iii%KOH&00f was added and mixed, followed by stirring to obtain Tex.

This latex Solid content 21r, 7wt-i% pH7・Hiro Average particle size 0.6-2μm Met.

[Production of graft copolymer]

SL with stirring device, heating and cooling device, and raw material charging device, in the reactor, small particle size rubber “Latexco 24/Of-” and large particle size rubber “Latexco J7f”
I prepared it. Potassium persulfate as initiator2. t t was dissolved in deionized water 601 and added, and the temperature was raised to 20° C. to initiate polymerization. To this, 10 styrene-acrylonitrile mixtures having the mixing specific gravity listed in Table 1 were added.
It was added continuously for 3 hours from the start of polymerization. continue,
A solution of potassium persulfate t, rf in 170 t of deionized water was added for 2 hours and 30 minutes from 30 minutes after the start of polymerization.
It was added continuously over several minutes.

After 30 minutes from the start of polymerization, / 0% KO)
I aqueous solution 111. II-f and terpene mixture, co?
was added, and further after 7 hours and 1 hour 30 minutes after the start of polymerization.
After a few minutes had elapsed, a solution of higher fatty acid i/f in deionized water at 20 fVC was added.

After the continuous addition of monomers was completed, the reaction was continued for an additional 30 minutes, and then the reactor was cooled. After adding an antioxidant to the obtained copolymer emulsion.

The mixture was heated to 0° C. and solidified dropwise in an aqueous MgBO4 solution with IC stirring. The obtained crumb was washed with water and then dried.

Table 1 St: Styrene AN: Acrylonitrile [Preparation of impact-resistant thermoplastic resin composition] The obtained graft copolymer [corresponding to a mixture of a part of Al and (B)] is further copolymerized. Polymer (as part of II, acrylonitrile residue amount az, 411R% styrene-acrylonitrile copolymer [Mitsubishi Sonsanto Kasei ■Product name rsAN■-/J]'jr blended to reduce the rubber content /
J weight was adjusted to - to prepare a resin composition.

[Measurement of physical properties]

A test piece was prepared from the above resin composition by injection molding.

Izot impact strength (20 (L) s, Vicat softening point (vicat), melt flow rate) (Ml
! The tensile strength (yield value), elongation (cutting value) and bending strength were measured using 6171 on Jl8.

FD engineer is F! effects Technology
Measuring device Ff'l'' Knee T200/E
I added one using T knee 300.

In other words, a falling weight with a spherical tip with a diameter of "1" is fixed at a predetermined level, and it falls from the height of the foot to the center of a plate-shaped molded product with a thickness of J and J. The total energy required for destruction was measured.

The measurement results are shown in Table 2.

Claims (2)

[Claims] (1) A copolymer (A) consisting of a diene rubber in which a graft chain consisting of an aromatic vinyl monomer residue and an unsaturated nitrile monomer residue was formed, and an aromatic vinyl monomer residue and Copolymer consisting of unsaturated nitrile monomer residues (B
), in which the content of the diene rubber is 10 to 30% by weight, the gel particles in the copolymer (A) have an average particle size of 0.1 to 0. 4μ
20-95% by weight of m, and the average particle size is 0.4
80 to 5% by weight of ~1 μm, and
The difference between the content of unsaturated nitrile monomer residues in the graft chain of copolymer (A) and the content of unsaturated nitrile monomer residues in copolymer (B) is within 1% by weight. composition. (2) The composition according to claim 1, wherein the content of unsaturated nitrile monomer residues in the graft chain of the graft copolymer (A) is 20 to 35% by weight.