JPS60245614A - Rubber-modified styrene resin - Google Patents

Abstract

PURPOSE:A rubber-modified styrene resin having an excellent gloss, prepared by graft-copolymerizing a styrene monomer with a specified commercially available polybutadiene. CONSTITUTION:The desired rubber-modified styrene resin is obtained by graft- copolymerizing 95-85wt% styrene monomer with 5-15wt% polybutadiene having a 1,2-bond content of 8-25% so that the following requirements may be satisfied. Said requirements are that the above-obtained resin has a solution viscosity as determined at 30 deg.C in a 5wt% solution of said polybutadiene in styrene of 25-70cSt and that the gel particles dispersed in said resin have a weight-mean particle diameter of 0.5-1.5mum and a degree of swelling of 7-11.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to rubber-modified styrenic resins having excellent thermal properties.

Conventional technology Rubber-modified styrenic resins, so-called high-impact polystyrene (HIPS), are polybutadiene.

Styrene and α-methylstyrene in diene rubber such as styrene-butadiene copolymer (SBR).

- A copolymer obtained by kraft copolymerization of a styrene monomer such as monovinyltoluene, or a blend of polystyrene and other monomers to adjust the rubber content of the copolymer. homopolymer]
It is more impact resistant and cheaper than ABS resin! It is widely used as a material for the casings of air equipment, the inner boxes of electric refrigerators, etc.

Since the rubber modified styrenic resin contains rubber particles Z,
The surface gloss of the molded product is significantly lower than that of polystyrene, and the gloss is also not as good as that of ABEI resin, which is also a rubber-modified resin. - Depending on the application, such as the outer case of electrical equipment, a rubber-modified styrene resin with excellent surface gloss may be required for design reasons.

Excellent gloss? The rubber-modified styrenic resin that has
Conventionally, at least 70% by weight of the rubber used is
- polybutadiene containing yqo% or more of cis bonds,
Grafting ratios and average particle diameters Z within specific ranges are known (Japanese Patent Application Laid-Open No. 2003-110001).

However, although molded products made without such resin have excellent gloss, they suffer from uneven gloss, and in particular, uneven gloss occurs at the weld line.

Further, the amount of l and co-coupling metals is 10 to 3%.

The viscosity of a 10% by weight styrene solution at 30°C is 30~
Resins using polybutadiene 7, which has a molecular weight of 60 centistokes, are also known (% Kaisho Ma 6-7 Koio issue); It has been difficult to obtain special polybutadiene industrially.

Problems to be Solved by the Invention The present inventors use industrially available rubber to develop a rubber-modified styrenic resin that has excellent gloss and does not cause uneven gloss or fire in molded products. The present invention was arrived at after seven years of intensive research.

Means for Solving the Problems The above object of the present invention is to reduce f-2%! , polybutadiene containing co-binding alloy! In the rubber-modified styrenic resin obtained by graft copolymerizing styrenic monomers qs to gs*'A%t to F-/j weight i%, a solution of the above-mentioned polybutadiene triple:11% styrene solution at 30 ° C. Achieved by a resin having a viscosity of 2S to 70 centistokes, a weight average particle size of gel particles dispersed in the resin of 0.3 to 1, and a swelling degree of 7 to 1/1. It will be done.

Structure of the Invention The polybutadiene used in the present invention (containing ↓, /, j bonds in l −2!%) is suitable.

If the content of L and Co bonds is less than 3%, uneven gloss will occur, especially at the weld line, and the content of Co bonds will be less than 3%.
If it exceeds Y, impact resistance decreases, which is not preferable.

Such polybutadiene is generally converted to butadiene using a Li-based catalyst. It cannot be obtained by solution polymerization, and its microstructure has a content of 7. Co-coupling, and /
, +cis bond 30 to lIO% and/or 41) lance bond 6θ to -0% is generally contained.

In this specification, the microstructure of polybutadiene is determined by the Morello method [D, Morero et al.
l, Chim, e-engineeringneL, 14171g(]qs9
)).

Furthermore, as the polybutadiene used in the present invention, j
The viscosity of the 9% styrene solution at 30°C is 23~
70 centistokes is suitable. , 1.
If it is less than 3 centistres, the impact resistance will decrease,
If it exceeds 70 centistokes, the gloss deteriorates, which is not preferable.

In the resin according to the present invention, polybutadiene and styrene-based I
It is formed by grafting IL molecules. So-called gel particles are dispersed, and the average particle diameter of such gel particles is suitably in the range of 0.8 mm to .08 μm. If it is less than o, rttm, the impact resistance will decrease.

/, If it exceeds 1 μm, the gloss deteriorates.

Further, the degree of swelling of the gel particles is suitably in the range of 7 to 1/l. If the degree of swelling is less than 7, the impact resistance will decrease, /IY:
If it exceeds the weld line, the gloss will change at the weld line, which is not preferable.

In the present invention, the degree of swelling is defined as 1. Gel particles obtained by centrifuging a quadruple weight methyl ethyl ketone solution of the resin according to the present invention are dried at 60° C. under reduced pressure until there is no weight loss, and then the measured weight t Y W.

Then, the dried gel particles were dispersed in a large excess of toluene and left at room temperature for two hours. ; It is expressed as Wl/WO, where Wl is the weight of gel particles obtained by centrifugation at 3°C for 2 hours at OOG acceleration.

What is the amount of polybutadiene used above? ˜is weight % is suitable. If it is less than 3% by weight, it is undesirable because the impact resistance will decrease and the production rate will also decrease.If it exceeds zhwt%, the viscosity of the styrene monomer solution of polybutane diene will be high and polymerization will be difficult. This is not preferable since there are problems such as the stirring power at the time being too strong.

Examples of the styrene spinning wheel matrix used in the present invention include styrene, α-methylstyrene, ψ-vinyltoluene, a vinyltoluene compound containing 90% or more of f-vinyltoluene, or a mixture thereof. The amount of styrene-based monocylindrical material to be used is 93 to 3 g by weight.

The method for producing the resin according to the present invention is preferably a bulk-suspension polymerization method.

That is, polybutadiene is dissolved in a styrenic polymer to a predetermined concentration, and a rubber-containing polymer is prepared by thermal polymerization or in the presence of a radical polymerization initiator and a chain transfer agent.
! % by weight, followed by the resulting syrup! It is dispersed in hot water containing a suspending agent and subjected to suspension polymerization.

Examples of the radical polymerization initiator include organic peroxides such as di-ter-butyl peroxide-ter-butyl perbenzoate and benzoyl peroxide, and azo compounds such as azobisisobutyronitrile. Examples of chain transfer agents include mercaptans such as ter-dodecyl mercaptan, and guacrylic acid. Water-soluble polymers such as polyvinyl alcohol are used. In addition, graft copolymerization 7 is carried out under conventional bulk-suspension polymerization conditions.

The resin according to the present invention may be used alone or in a composition with polystyrene. Also, depending on the bag, antioxidants and lubricants.

It can also be used as a composition containing auxiliary agents such as colorants.

Effects of the Invention Molded products made using the rubber-modified styrenic resin according to the present invention have a surface gloss comparable to that of ABS resin, and no uneven gloss at the welt line boundary is observed. . Furthermore, since industrially available polybutane is used, it can be easily produced.

Example Next, the present invention will be specifically explained based on Examples.

In addition, in the examples, the weight average particle diameter of the gel particles was measured in the following manner.

41. Rubber-modified styrenic resin. The weight-average particles were determined from the particle size distribution curve obtained by centrifuging the wt% methyl ethyl ketone solution to separate the gel particles, and measuring the resulting gel particles using a 7 wt% dimethylborumamide dispersion using a Coulter counter. I adjusted the diameter.

The solution viscosity of polybutadiene was measured using a Cannon-Fenske viscometer.

DuPont type falling weight impact strength (FD Eno is used as a sample)
A 0IIWIIX 7! ; A square plate of IHX and SMU was used as a striking core, and a 1-inch one was used as the striking core. The energy was expressed as the energy when a crack occurred in the sample.

The Izotsu impact strength is measured as a direct %t/ε inch x
Measurements were made using a 4-inch long round bar using a J-Tech SK-RI//Q.

Surface gloss is JIS K-71.0! It was measured by ;

The uneven gloss bordering the weld line is measured as a sample.
, 0 fight x ri 5 fight x co, s A KJ square plate was used and was observed from an oblique direction with the naked eye. The evaluation was based on the following criteria.

A: There is almost no uneven gloss bordering on the weld line.

B: There is slight uneven gloss at the weld line 7 boundary.

C: There is considerable unevenness in gloss bordering on the welt line.

Example 1 In a dissolution tank with contents 8 yen 20073, l, Co-bonded gold-Mll, l, Gusis content 37%-'rlI) lance content jJ
%, polybutadiene with RM viscosity < t3 centistokes (Zeon BR-/244/BL) lOkg, 9
0 kFI of styrene and trisnonylene/l/phenylphosphite (7,/kgi) were charged and dissolved by heating and stirring at 70° C. for S hours.

The obtained molten g was charged into a prepolymerization tank with an internal volume of
Add 0.0/kg of ter-butylene/L/perhensoate and 0.0 kg of ter-dodecyl mercaptan and carry out bulk polymerization with stirring at °C until the polymer component containing rubber becomes 1/-0% by weight. I did it.

In a main polymerization tank with an internal volume of 3001, water was added, and acrylic acid and acrylic acid ester copolymers were added as suspending agents.
g kg polyvinyl alcohol 0.07 kP, gi MgSO40,,2,, as a clouding aid! To l-! 9. Na
25o40,/! Pour 1 g of 9' into and dissolve it, add the entire amount of the syrup obtained in the above bulk polymerization step,
Stir to disperse. To this was added 0.0% ter-butyl perbenzoate. Is it 3kl? In addition, heat at 1117°C for 1 hour.

Polymerization was carried out with stirring at /4 (0°C for 1 hour and /!fAr°C for 1 hour).

The obtained beads were dried separately and added with antioxidant (Irganox 7.074-Ciba Geigy) 0.0, 0.23, and zinc stearate 0.00. ,? kfl'fl was added and pelletized using an extruder.

The results obtained are shown in Table 2.

Examples 3 and 3 Comparative Examples 7 to 3 Rubber-modified styrenic resins were produced in the same manner as in Example 3, except that the polybutadiene was changed.

The polybutadiene used and the results obtained are shown in Table 7. In Comparative Examples 7 to 3, gloss unevenness bordering on weld line quality was observed.

Comparative Example G, 5 Difference in physical properties due to difference in particle size of gel particles? I did a lot of research. The results are shown in Table 1. In Comparative Examples y and I, there was no uneven gloss between 1 gloss and weld line χ.

Comparative Example 6.7 In order to investigate the difference in swelling degree of gel particles, the reaction condition f4 at the final stage of the suspension polymerization process was used in Comparative Example t.
The waiting time was set to /Sj°Cy time in Comparative Example 7. The results are shown in Table 7.

In Comparative Example 6, there was uneven gloss bordering on the weld line, and in Comparative Example 7, the impact strength, particularly the Izot spinal water strength, was poor.

Procedural amendment, written (spontaneous) Date: r 2, 1980/Indication of case: 1982 Patent Application No. 10029/λ
Title of the invention Rubber-modified styrenic resin 3 Relationship to the case of the person making the amendment Patent applicant name (60 cases) Mitsubishi Monzant Chemical Co., Ltd. and agent Address: No. λ, S, 2-chome, Marunouchi, Chiyoda-ku, Tokyo, 700, Japan Contents of the amendment (1) Line 72 of the first page between specifications "θ/, 5'~/6-
"Weight average particle diameter" is corrected to "Weight average particle diameter of θ/!i~/Jpm".

(2) Page 7, line 1g of the specification “30 to 1l-s weight%
" is corrected to "30~SS weight%".

(3) Lines 1 to λ of page 10 of the specification are corrected as follows.

"The Izod impact strength is determined by using a test piece with a thickness of 31mm - width/near width and length A3.3wn as a sample, and correcting JISJ (4) Specification No. 1/Page 1 line 1 as follows. .

"Copolymer 0.0g K9, polyvinyl alcohol 0
07" or above

Claims (1)

[Claims] (x) g-, 2 left candy/, polybutadiene S~/ containing the yu bond! iMV% to styrenic monomer 9-g
In the rubber-modified styrenic resin obtained by graft copolymerizing kN amount %, the solution viscosity of the left-gravitational styrene solution of the polybutadiene at 30° C. is U S ~ 70 centistokes, and the gel dispersed in the resin Particles are 0. ! ;-/, has a weight average particle diameter of μm, and
A resin characterized by having a degree of swelling χ of 7 to //.