JPS63241015A - Dispersion of graft rubber particle - Google Patents

Abstract

PURPOSE:To obtain a dispersion of rubber particles comprising a rubber-like butadiene polymer produced by anionic polymerization, which has a high gloss and excels in, especially, low-temperature impact resistance. CONSTITUTION:This graft rubber particle dispersion comprises a rubber-like butadiene polymer produced by anionic polymerization, has a styrene-insoluble component content <0.1wt.%, and satisfies the following requirements A-C: [A] these rubber particles contain an occluded and/or grafted copolymer (M) of a styrene monomer with an acrylonitrile monomer, and the amount of copolymer M is 10-100pts.wt. per 100pts.wt. rubber-like polymer [B] these rubber-like particles contain rubber particles having a maximum diameter of a cell within a rubber particle <0.1mu in an electron-microscopic photograph of an ultra-thin slice of the rubber particle dispersion, and [C] the volume-average particle diameter of these specified rubber particles is 0.1-0.4mum, and the number of these specified rubber particles amounts to 80% of that of the entire particles observed in the ultra-thin slice electron-microscopic photograph.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to resins used as molding materials, and relates to the impact resistance, appearance, and abrasion resistance of molded products.

Concerning materials with excellent heat aging resistance. The rubber particle dispersion (hereinafter referred to as RDR) of the present invention is used, for example, as a molding material for parts of electrical equipment, automobiles, etc., and specifically, for example, housings of telephones and computers, automobile interior parts, and exterior parts. It is used as such.

[Conventional technology]

Preferred molding materials for each of the above parts include a material in which particles of a rubbery polymer (hereinafter referred to as rubber particles) in which a copolymer of a styrene monomer and an acrylonitrile monomer is occluded and/or grafted (hereinafter referred to as rubber particles) are dispersed; For example, “ABS resin”
, P, 79. P, 80 (1970), Polymer Mechanical Materials Committee. Electron micrographs show that more ABS resins have been used in the past.

However, in recent years, in the electrical equipment field, automobile field, etc.
The scope of use of resins has expanded, and the performance requirements for the resins used have become more sophisticated.

[Problem that the invention seeks to solve]

These required performances include extremely high gloss, high impact strength even in thin-walled molded products with complex shapes, particularly high impact strength at low temperatures, and even higher impact strength when molded at higher temperatures. It is becoming increasingly important to maintain high resistance to deterioration.

The present invention has been made in response to such a need, and it has been found that the problem can be solved by providing a dispersion of rubber particles special for the purpose Fi.

[Means for solving problems]

As a result of intensive studies in view of the importance of the above objectives, the present inventors have discovered a collection of rubbery polymer particles with a special internal structure containing a rubbery polymer produced by an anionic polymerization method that is completely new from conventional knowledge. He discovered that the purpose can be achieved by the body and completed the present invention.

That is, the present invention provides a dispersion of rubber particles made of a Poutadier/type rubbery polymer produced by anionic polymerization in which a styrene-insoluble component is less than 0.1 weight range, wherein A: the rubber particles are a styrene monomer; and a copolymer of an acrylonitrile monomer is occluded and/or grafted, and the amount of the occluded and/or grafted copolymer is 10 to 10 parts by weight per 100 parts by weight of the rubbery polymer.
0 parts by weight, B Rubber particles whose maximum cell diameter within the rubber particles is less than 01μ in an ultra-thin section electron micrograph of a dispersion of the rubber particles (hereinafter such rubber particles are referred to as RX) have,
and C, the volume average particle diameter of the RX is 0.1 to 0.4 μm, and when the number of all rubber particles taken in the ultra-thin section electron micrograph is taken as 100%, the number of RX is at least 8
This is a dispersion of rubber particles characterized by occupying a coefficient of 0.

The rubber particle dispersion of the present invention has a styrene-insoluble component of 0.
A dispersion of rubber particles of a rubbery polymer produced by anionic polymerization having a width of less than 1 weight. Regarding the form of such a dispersion of rubber particles, it may be exemplified by high impact polystyrene occluded and/or grafted with a styrene polymer different from the copolymer of the present invention (commonly referred to as HIP8). An example of such a HIPS is M, M, Bikale4 ed, Encyc
ropedia of Po17merScience
and Technology, vol. 13
, John Wiley & 5ons, New
Fig of York, 1970, P, 217
, 5. In this example, acrylonitrile is not included as a component of the polymer, but the concept of rubber particles and cells is the same as in the present invention. That is, the cells occupy almost the entirety of the rubber particle FiFig,5, and the cells are further dispersed within the rubber particle. The above rubber particles are exemplified.

The Petadier type rubbery polymer produced by anionic polymerization in the present invention is distinguished from the rubbery polymer produced by radical polymerization. In the latter case, the object of the present invention cannot be satisfied in terms of gloss, impact resistance, and impact resistance at low temperatures. Rubbery polymers produced by such anionic polymerization include solution polymerization Ziegler catalysts,
A rubber-like polymer produced using a CO-based catalyst or a Li-based catalyst, and those using a Li-based catalyst are preferably used.
For example, Saiki crude oil “Polymer production process”, P. 21
9-272 (1971), exemplified by Industrial Research Council h
ing. Examples include polybutadiene rubber, butadiene styrene copolymer and other copolymers, preferably butadiene styrene copolymer, particularly preferably butadiene styrene copolymer, etc.
An example is a styrene block copolymer. Among the butadiene-styrene block copolymers, those having a styrene content of 3 to 28 parts by weight are preferably used to achieve the object of the present invention. Also, the 5 weight range styrene solution viscosity is 100 to 2 centipoise, preferably 60 to 2 centipoise, more preferably 4 centipoise, as measured at 30'O.
0 to 5 centipoise, particularly preferably 19 to 5 centipoise can be used.

Conventionally, rubber particles made of a butadiene-based rubbery polymer occluded and/or grafted with a copolymer of a styrene monomer and an acrylonitrile monomer have been produced by radical polymerization. The origin of the outstanding performance of the rubber particle dispersion (hereinafter referred to as RDR) of the present invention is not clear, but the rubber-like polymer obtained by such radical polymerization is characterized by its microstructure, amount of styrene-insoluble components, and polymer composition. There are differences in impurities such as emulsifiers contained, and especially in the case of block-type butadiene-styrene copolymers, they cannot be substantially reached by radical polymerization, and it is assumed that these impurities are related to the structure. Ru.

The RDR of the present invention has a maximum cell diameter of 0.1 within the rubber particles.
It must have rubber particles (RX) that are less than μm, preferably less than 0.07 μm. Maximum cell diameter is 0
．． If the thickness is 1 μm or more, the effect of the present invention cannot be obtained.

In the RDR of the present invention, the volume average particle diameter of RX is 0.1 μm to 0.4 μm, preferably 0.15 to 0.1 μm.
It is 35 μm, particularly preferably 0.18 to 0.32 μm. If it is less than 0.1 μm, the impact resistance will be poor, and if it exceeds 0.4 μm, the impact resistance will be poor, and the gloss of the molded product will be reduced.

In the RDR of the present invention, when the number of all rubber particles taken in an ultrathin section electron micrograph of RDR is taken as a factor of 100, the number of RXs must account for at least a factor of 80. The effects of the present invention are manifested by RX of butadiene-based rubbery polymers produced by anionic polymerization, and if the number is less than 80%, the object of the present invention cannot be achieved. .

The rubber particles in the RDR of the present invention are made of a copolymer of styrene monomer and acrylonitrile monomer and/or
The amount of such occluded and/or grafted electrolyte, coalescence is 10 to 100 parts by weight, preferably I
I'i is 15 to 45 parts by weight, particularly preferably 20 to 45 parts by weight.

If it is less than 10 parts by weight, the impact resistance will be low, and if it exceeds 100 parts by weight, the desired appearance, especially gloss, will not be achieved.

The ratio W of the copolymer of styrene monomer and acrylonitrile monomer occluded and/or grafted by the rubber particles in RDR to 100 parts by weight of the rubbery polymer is determined as follows. That is, R, DR (approximately 1)
Disperse (accurately weigh) at in a mixed solvent of methyl ethyl ketone/methanol, separate the insoluble matter by centrifugation and dry it, accurately weigh the weight of the insoluble matter (b?), and calculate it using the following formula. . However, C indicates the content (weight ratio) of the rubbery polymer in RDR.

In addition, if RDR contains additives that are insoluble in the above solvent, a
The values of a and b are obtained by subtracting the additive from the values of , b. C is the ratio of the rubber-like polymer, styrene monomer, and acrylonitrile monomer to the total amount of the copolymer in RDR.

Examples of methods for adjusting the value of W include the polymerization initiator, the intensity of stirring, the amount of rubbery polymer used, the amount and type of monomer, the molecular weight regulator, the final polymerization rate, or the devolatilization step. It is adjusted depending on the conditions, and in general, the larger the amount of polymerization initiator, the lower the degree of stirring, the more diene component in the rubbery polymer, the less rubbery polymer, the more styrenic monomer. Although the amount of W tends to increase as the temperature of the devolatilization step increases, those skilled in the art can adjust the desired value of W by adjusting this amount using the trial-end error method.

In the RDR of the present invention, styrene monomers and acrylonitrile monomers are produced by solution or bulk polymerization in the presence of a butadiene rubber polymer produced by anionic polymerization in which styrene-insoluble components are less than 0.1 weight percent. It is produced by polymerizing polymers, preferably by a continuous solution or bulk polymerization method, and is distinguished from ABS resin produced by an emulsion polymerization method using a rubbery polymer latex. In such polymerization, a styrene monomer (hereinafter referred to as S) and an acrylonitrile monomer C (hereinafter referred to as A) are used in the coexistence, and the S/A ratio is 10.
/90 to 90/10, more preferably 10/90 to 50
150 is preferably used. A chain transfer agent is also used as a molecular weight regulator, especially at the initial stage of the reaction, when the polymerization conversion rate is less than 30% by weight.
Mercaptans such as n- or t-dodecyl mercaptan are preferably used in a proportion of 1000 ppm. In addition, the organic peroxide is 10 to 100 ppm of monomer.
and the reaction is preferably carried out at 50 to 100 °C. In the continuous solution or bulk polymerization method, after the rubbery polymer of the present invention is completely dissolved in the monomer and optionally the solvent, the solution is fed continuously or into a multi-stage series or parallel reactor. Polymerization reaction is carried out continuously. In such examples, the so-called phase transformation (phase 1
By selecting the molecular weight regulator, organic peroxide, polymerization rate, temperature, amount of solvent, and stirring intensity at the step of 1. Cell diameter can be adjusted. The stirring intensity is the product D of the blade diameter D (m), the stirring number n (r, p, m,), and the stirring power per unit volume P (KW / m-).
It is preferable that nP is 10 Kvsm*r,p,m,/m' or more. If the aforementioned S/A ratio is less than 10/90, the impact resistance will be extremely low, and if it exceeds 90/10, particle formation will become difficult.

In the present invention, the volume average diameter of RX is measured as follows.

That is, an electron micrograph of RDR at 20,000 times magnification was taken using the ultra-thin section method, and 500 to 80% of the RX rubber particles in the photograph were
00 particle diameters were measured and averaged using the following formula. Di is the average diameter of the first piece.

Volume average particle diameter = ΣD1/ΣD13 n n (However, n is the number of all rubber particles.) Also, when determining the above D1 and cell diameter using an electron microscope using the ultrathin section method of RDR, it was found that the rubber particles and cells were elliptical. In this case, the average value of the major axis a and the minor axis a is taken as the diameter α. That is, a = (a + b) / 2. In addition, when calculating the proportion of cells with a diameter of less than 0.1 μm, we randomly measured a total of 500 to 700 rubber particles using at least one photograph of at least 200 rubber particles. This is what I am looking for.

In the RDR of the present invention, the crosslinking degree index of the dispersed phase is 8 to 1.
It is preferably 6 times, more preferably 9 to 14 times, particularly preferably 10 to 14 times. The crosslinking degree index of such a dispersed phase is measured by the following method.

RDRo, 4? Q Partially dissolve in 30 cc of toluene/methyl ethyl ketone mixture ratio 7/3 liquid.

After centrifugation, the weight of the insoluble matter swollen with the solvent is weighed (W
l) Do. After weighing, the insoluble matter is vacuum dried and weighed again (W
2) Do. The crosslinking degree index is obtained by Wl÷W2. The crosslinking degree index depends on the amount and type of polymerization initiator, the temperature and residence time during devolatilization treatment, and further depends on the amount of maleimide monomer. Those skilled in the art can set an appropriate degree of crosslinking index by selecting manufacturing process conditions by trial and error. When the crosslinking degree index is less than 8, the impact strength is extremely low and the fluidity obtained is also low. Moreover, even if it exceeds 16, the practical impact strength becomes small.

The styrenic monomers used in the present invention include styrene, styrene substituted with side chain alkyl such as α-methylstyrene, α-ethylstyrene, monochlorostyrene, dichlorostyrene, vinyltoluene, vinyl 7ゝxylene, 0- Nuclear alkyl-substituted styrenes such as t-butylstyrene, pt-butylstyrene, p-methylstyrene, halogenated styrenes such as tribromustyrene, tetra7'' labromstyrene, and p-hydroxystyrene, 0-methoxystyrene , vinylnaphthalene, etc., and particularly preferred are styrene and α-methylstyrene, and one or more of these styrenic monomers may be used.

Examples of the acrylonitrile monopolymer used in the present invention include acrylonitrile, methacrylonitrile, fumaronitrile, maleonitrile, and α-chloroacrylonitrile, with acrylonitrile being particularly preferred. One or more such monomers may be used.

In the present invention, a part of the styrene monomer and acrylonitrile monomer of the copolymer component is 30% by weight or less based on the total of the styrene monomer and the acrylonitrile monomer. methacrylic ester monomers such as methyl methacrylate, acrylic ester monomers such as methyl acrylate, maleimide, N
- It may be constructed by replacing it with one or more maleimide monomers such as phenylmaleimide. For the purpose of improving heat resistance, it is preferable to replace the maleimide monomer with 1 to 30 parts by weight.

The DR of the present invention can be improved with ordinary hindered phenol or a lubricant can be added to further improve the fluidity. In addition, fiber reinforcing agents such as glass fiber,
Inorganic fillers, colorants, and pigments can also be blended. Further, flame retardation can be achieved by mixing a partially halogenated organic compound flame retardant such as tetrapromosbiphenyl A, decaglomobiphenyl ether, brominated polycarbonate, etc. with antimony oxide in the RDR of the present invention.

The RDR of the present invention can be molded by blending with resins such as AB8 resin, polyvinyl chloride, styrene-acrylonitrile resin, polycarbonate, polybutylene terephthalate, polyethylene terephthalate, nylon 6, nylon 66, nylon 12, polyphenylene oxide, and polyphenylene sulfide. You can also donate.

〔Example〕

Hereinafter, specific embodiments of the present invention will be shown by Examples and Comparative Examples, but these are not intended to limit the present invention.

Example I A Production of a dispersion of rubber particles R, DR=i was produced using a continuous bulk polymerization apparatus in which a preheater and a vacuum tank were connected to the outlets of four reactors equipped with agitators in series. Block 8BFL (styrene 18, butadiene 82, the microstructure of the butadiene part is vinyl l
6 mol %, trans 4 B mol, cis 36
Mol ratio, 5 weight ratio styrene solution viscosity is 10 centipoise at 30°C, styrene insoluble content 0.02 parts by weight)7
Parts by weight: 15 parts by weight of ethylbenzene, 55 parts by weight of styrene]
1 to 31 parts of acrylonitrile and 23 parts by weight of acrylonitrile, and an organic peroxide and a chain transfer agent were added thereto to form a homogeneous solution. This rubber solution is continuously fed into the first reactor for continuous polymerization and then passed through the fourth reactor.
30'C! The unreacted monomer and solvent were removed in a vacuum chamber at a vacuum degree of 150 torr through a preheater maintained at a temperature of 150 torr, and the resin was continuously extracted from the vacuum chamber to obtain R and DR. 185 ppm of organic peroxide as a polymerization initiator
150 ppm of n-dodecyl mercaptan was used as a molecular weight regulator. The amount of rubbery polymer in RDR was calculated from the amount of feed raw materials supplied and the amount of RDR obtained. The stirring number of the first reactor is 320 r, p, m.

Met.

Analysis of BRDR B-1 Rubber content: The amount of rubber in the resin was obtained from the balance between the amount of rubber fed to the reaction system and the RDR produced as described in A, assuming that the total resin was 100 parts by weight.

B-2 Cell diameter and average rubber particle diameter (X-): According to the method described in the detailed explanation.

B-3 Amount of copolymer of styrene monomer and acrylonitrile monomer occluded and/or grafted by rubber particles: according to the method described in the detailed description.

B-4: Styrenic monomer (S) and acrylonitrile monomer (S) of occluded and/or grafted copolymer (
It was determined by the two-element composition analysis method described in 5).

Evaluation of performance C-1 Molding: After drying the 4-iron RDR at 75'O for 2 hours, the molding temperature was 200'C! , using an injection molding machine at a mold temperature of 55°C.

C-2 Evaluation of physical properties (1) Izot impact strength: JISK-7110
It was evaluated accordingly. Evaluation was made at 23°C and -45°C.

(2) Gloss: Evaluation was made according to JISK-7105.

A rectangular molded product with a width of 50M11, a thickness of 2.5 mm, and a length of 150 m11 was injection molded. The gate has a width of 501 m + a thickness of Q, 1 mm and is placed at one end in the length direction, with the gate portion serving as the flow starting point and the end opposite to the gate serving as the flow end. 5 vi with the center located at a distance of 25 meters from the gate part
5 tm X The gloss of the 5 m square part is taken as the gate gloss, and the center position is 25 meters from the end.
The gloss of the square part of 51111 was defined as the bundle end gloss. In general, the difference in the gloss of the gate part for different RDRs is smaller than the difference in the end part, and the gloss value of the end part is significantly lower than the gloss of the gate part.In practice, the gloss of the end part is the important point in terms of appearance. It is.

(3) Evaluation of practical impact strength: Figure 1 (a) by injection molding
, three parts of the molded product having the shape shown in FIG. 1(b),
A falling weight impact strength test was conducted on portions (1), (2), and (3). Tip of falling weight R = 6.4 m/
m, and the inner diameter of the pedestal was 30 m/m. Part (1) is the part where the thickness changes, part (2) is the part near the corner,
Site (3) is a standard site.

Evaluation was made at temperatures of 23°C and -45°C.

(4) Evaluation of thermal deterioration due to heating retention = When molding the glossy flat plate in (2), the normal conditions are the above-mentioned 200°C, or the injection molding temperature is 2700°C, and the cylinder is heated to 10°C.
The degree of yellowing was measured based on normal conditions (retention time: 1 minute).

(5) Evaluation of fluidity during molding process: Evaluation was made based on the oil pressure of the molding machine required for the lowest injection pressure (short shot oil pressure) to prevent short shots from occurring during injection molding. A commercially available high-rigidity ABS (reference example) manufactured by an emulsion polymerization method was used as a standard, and relative evaluation was performed based on the difference in short shot oil pressure. If the difference value is negative, it indicates that the oil pressure is lower than that of the reference example, and it is determined that the material has good fluidity during molding.

D Results are shown in Table 1.

Comparative Example 1 In Example 1, the amount of ethylbenzene was 25 parts by weight, the amount of styrene was 48 parts by weight, and the amount of acrylonitrile was 20 parts by weight.
In terms of parts by weight, the stirring number of the first reactor was 140 r.
, p, m, and n-dodecyl mercaptan to 300
RDR was produced in the same manner as in Example 1, except that the amount of rubber in RDR was the same as in Example 1 in terms of ppm. Table 1 shows the analysis and performance evaluation results.

Comparative Example 2 In Comparative Example 1, the rubbery polymer was polybutadiene (microstructure: vinyl 20 mol tly, trans 47 mol %, cis 33 mol %, styrene solution viscosity of 5% by weight was 40 centipoise at 30°C, styrene insoluble). RDR was produced in the same manner as in Comparative Example 1 except that 0.02 parts by weight) was used. Table 1 shows the analysis and performance evaluation results.
Shown below.

Comparative Example 3 Styrene-butadiene random copolymer rubber latex produced by radical polymerization different from the rubbery polymer of the present invention (styrene insoluble component 92 parts, styrene component composition 19 parts by weight, microstructure: vinyl 20 moat, cis 12 parts) m
ox factor, transformer 5 Q mol factor, solid content 20%, volume average diameter of latex 0.25 μm) e using styrene,
Copolymerization was carried out while continuously adding acrylonitrile to obtain R and DR. Table 1 shows the analysis and physical property evaluation results.

Example 2 RDR was produced and evaluated in the same manner as in Example 1 except that the stirring speed was tripled.

The results are shown in Table 1.

〔Effect of the invention〕

As detailed above, the rubber particle dispersion of the present invention has extremely high gloss and impact strength, has excellent low-temperature impact resistance, has high gloss at the flow end, has excellent heat stability, and is colorable with pigments. It also has excellent coloring properties over time. Furthermore, copolymerized maleimide monomers have a high heat resistance and are suitable for use in parts materials for electrical equipment, electronic equipment, automobiles, office equipment, etc., and for blending with other resins. It has extremely great industrial value in applications such as industrial applications.

[Brief explanation of drawings]

Figure 1 shows the shape of the molded product used in the practical impact test. (
Figure a) is a plan view, and figure a) is a cross-sectional view. G indicates the gate position. Patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Scope of Claims] 1. A dispersion of rubber particles made of a butadiene-based rubbery polymer produced by anionic polymerization and having a styrene-insoluble component of less than 0.1% by weight, wherein the rubber particles are a styrene-based monomer. and a copolymer of acrylonitrile monomer is occluded and/or grafted, and the amount of the occluded and/or grafted copolymer is 10 to 10 parts by weight per 100 parts by weight of the rubbery polymer.
0 parts by weight, B. Rubber particles having a maximum cell diameter within the rubber particles of less than 0.1 μ in an ultrathin section electron micrograph of the dispersion of the rubber particles, and C. The volume average particle diameter of the rubber particles is 0.1 to 0.
4 μm, and the number of the specific rubber particles accounts for at least 80% when the number of all rubber particles taken in the ultra-thin section electron micrograph is taken as 100%. Dispersion.