JP3152709B2 - Rubber-modified impact-resistant resin composition and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber-modified impact-resistant styrenic resin having excellent impact resistance and physical properties having excellent appearance characteristics such as gloss, and a method for producing the same.

[0002]

2. Description of the Related Art Impact-resistant styrenic resins, for example, impact-resistant polystyrene, have conventionally had drawbacks such as inferior gloss on the surface of molded articles and lower impact strength than ABS resins. In recent years, demand for thinner impact-resistant polystyrene having an excellent overall balance of impact strength, gloss, and the like has been increasing from the market due to the trend toward thinner walls and higher grades.

[0003] Further, the use of impact-resistant polystyrene is expanding, and the balance of physical properties required according to the use is also diversifying. Conventionally, impact-resistant polystyrene has been used as a rubbery polymer as polybutadiene rubber, butadiene-
A method of dissolving a styrene copolymer rubber in a styrene monomer, dispersing rubber particles under polymerization stirring, and then subjecting it to bulk or solution polymerization, or subjecting it to suspension polymerization, a so-called bulk-suspension polymerization method. General.

In this case, the content of the rubbery substance is 3 to 10
% By weight was normal. Further, when the amount of rubber is increased, the viscosity in the polymerization apparatus rises, hindering stirring, and it is difficult to control the diameter of rubber particles in the resin, which is not easy. For this reason, a production method using polybutadiene having a relatively low solution viscosity (JP-B-58-4934) is disclosed. Although a resin with improved quality can be obtained by such a method, it cannot be said that the recent demand for resin is sufficiently satisfied.

On the other hand, as another rubber-modified styrene-based copolymer, a rubber-modified styrene-acrylonitrile copolymer generally called an ABS resin is known. However, the resin obtained by the bulk polymerization method has a drawback that it is inferior to the resin obtained by the emulsion polymerization method in balance of mechanical strength and physical properties of appearance. For this reason, a satisfactory resin has not been obtained in the bulk polymerization method or the bulk-suspension polymerization method.

As a method of improving such a defect, for example, a resin using a rubbery polymer having a low solution viscosity (Japanese Patent Laid-Open No.
3-199717, and JP-A-63-20780
No. 3) is disclosed. However, resins using these low-solution viscosity rubbery polymers are not necessarily satisfactory in appearance characteristics and the like. In addition, a low solution viscosity rubbery polymer having a structure as used,
Cold flow was severe and there was a problem in workability when handling industrially.

[0007]

In view of such circumstances, the present inventors diligently aim to obtain a rubber-modified impact-resistant polystyrene resin having a highly balanced mechanical strength and appearance characteristics. As a result of the study, by using a butadiene-styrene copolymer rubber having a specific structure and a polybutadiene rubber blended in a specific ratio,
The present inventors have found that a rubber-modified impact-resistant styrene-based resin that has achieved the above objects can be obtained, and have accomplished the present invention.

That is, the present invention provides: (1) (A) (a) the bound styrene content (TS) is 2 to 1;
(B) Solution viscosity (SV) is 5 to 50 centipoise (cps), (c) Mooney viscosity (ML) is 20
１５０150, (d) ML / SV ratio is 3-7, (e) T
The relationship between S, SV and ML is given by the following equation (1):

[0009]

(3) a butadiene-styrene copolymer rubber satisfying −50 ≦ [(ML × 2) − (SV × TS)] ≦ 50 (1)

(B) A rubber-like polymer having a solution viscosity of 10 to 100 centipoise in a weight ratio of butadiene-styrene copolymer rubber to polybutadiene rubber in the range of 95: 5 to 30:70. 3-2
A rubber-modified impact-resistant styrenic resin composition characterized by containing 5% by weight; and

(2) (A) (a) Bound styrene content (T
S) is 2 to 15% by weight, and (b) the solution viscosity (SV) is 5
-50 centipoise (cps), (c) Mooney viscosity (ML) is 20-150, (d) ML / SV ratio is 3-
7, (e) The relationship between TS, SV and ML is expressed by the following equation (1):

[0012]

And a butadiene-styrene copolymer rubber having the following relationship: -50 ≦ [(ML × 2) − (SV × TS)] ≦ 50.

(B) A rubber-like polymer containing a polybutadiene rubber having a solution viscosity of 10 to 100 centipoise in a weight ratio of the butadiene-styrene copolymer rubber to the polybutadiene rubber in the range of 95: 5 to 30:70. 3-2
5 to 75% by weight of a mixture of 5% by weight of a styrene monomer or a monomer copolymerizable with a styrene monomer is subjected to bulk polymerization, bulk suspension polymerization or solution polymerization. Another object of the present invention is to provide a method for producing a rubber-modified impact-resistant styrene resin composition.

Hereinafter, the present invention will be described in detail. The rubbery polymer used in the present invention is a butadiene-styrene copolymer rubber having a limited structure (hereinafter abbreviated as a copolymer) and a polybutadiene rubber.

The bound styrene content of the copolymer used in the present invention is 2 to 15% by weight, preferably 4 to 10% by weight. The bound styrene content of the copolymer used is 15
If the content is more than 2% by weight, the impact strength of the obtained resin will be reduced. If the content is less than 2% by weight, the cold flow of the copolymer will be severe, and the operability will be poor in industrial handling.

Next, the solution viscosity of the copolymer used in the present invention is 5 to 50 centipoise, preferably 5 to 30 centipoise. When the solution viscosity is higher than 50 centipoise, the appearance properties of the obtained resin are deteriorated, and when the solution viscosity is lower than 5 centipoise, the impact strength of the obtained resin is reduced. The Mooney viscosity of the copolymer used in the present invention is 20 to 150, preferably 30 to 100. When the Mooney viscosity is less than 20, not only the impact strength of the obtained resin is lowered, but also it becomes difficult to industrially produce this copolymer. When the Mooney viscosity exceeds 150, the appearance characteristics of the resin are reduced.

Further, the ratio ML / SV of Mooney viscosity to solution viscosity of the copolymer is 3 to 7, more preferably 3.5 to 7.
It is limited to the range of 6. If it is smaller than 3, the appearance characteristics of the obtained resin will be reduced, and the effect of the present invention will not be exhibited. If it is larger than 7, the impact strength is reduced. Furthermore, bound styrene content (TS) and Mooney viscosity (M
L) and the solution viscosity (SV), the following equation (1) needs to be established.

[0018]

-50 ≦ [(ML × 2) − (SV × TS)] ≦ 50 (1) The above formula (1) represents TS, SV, ML of the butadiene-styrene copolymer rubber used in the present invention. Is a special area.

More specifically, although the respective values of TS, SV, and ML are conventionally known regions, their limited combinations are an important part of the present invention. When the value of the above formula (1) is out of the range of the present invention, the attack strength of the obtained resin decreases.

On the other hand, the other polybutadiene used as the rubbery polymer has a solution viscosity in the range of 10 to 100 centipoise. If the solution viscosity is less than 10 cps,
The impact strength of the obtained resin is not sufficient, and if it exceeds 100 cps, the appearance characteristics are deteriorated.

Next, the weight ratio of the butadiene-styrene copolymer rubber to the polybutadiene rubber is 95: 5 by weight.
30:70. If the butadiene-styrene copolymer rubber exceeds 95% by weight, the impact strength is not sufficient,
If the amount is less than 30% by weight, the appearance characteristics deteriorate.

Next, a method for measuring the butadiene-styrene copolymer rubber and the polybutadiene rubber used in the present invention will be described. The bound styrene content was measured by an ordinary method using an ultraviolet spectrophotometer. The 5% by weight styrene solution viscosity was measured at 25 ° C. using a Cannon-Fenske viscometer. Mooney viscosity is a value measured at ML _{1 + 4} (100 ° C.).

The butadiene-styrene copolymer rubber used in the present invention is usually produced in a hydrocarbon solvent using an organolithium catalyst. As the organic lithium-based catalyst, for example, n-propyl lithium, iso-
There are propyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, benzyllithium and the like, but preferably n-butyllithium and sec-butyllithium and the like.

Examples of the hydrocarbon solvent include aliphatic hydrocarbons such as butane, pentane and hexane; alicyclic hydrocarbons such as cyclopentane and cyclohexane; and aromatic hydrocarbons such as benzene, toluene and xylene. The copolymer used in the present invention can be produced by either a continuous polymerization method or a batch polymerization method, with the latter being preferred.

Further, since the values and relationships of the styrene content, solution viscosity, and Mooney viscosity are limited to specific ranges, the polymerization method requires some contrivance. In particular, the polymerization method is not limited. For example, by applying the polymerization method described in JP-A-55-35404, polymerization is performed by dividing the organolithium catalyst and the monomer respectively, and then the polyfunctional coupling is performed. It can be manufactured by coupling with an agent.

In this case, examples of the polyfunctional coupling agent include polyhalides such as trichloromethylsilane and silicon tetrachloride, diester acids such as adipic acid diester, and polyepoxysite and polyisocyanate.
Known materials such as polyamine can be used. Further, a polar substance such as triethylamine, tri-n-butylamine, hexamethylphosphoramide, diethyl ether, or tetrahydrofuran may be added to the polymerization system.

As an example of the production of the copolymer rubber used in the present invention, a solution containing styrene is prepared in cyclohexane in an autoclave, and tetrahydrofuran is added in an amount of 50 to 5,000 ppm with respect to cyclohexane.
After the temperature was raised to 0 to 80 ° C, n-butyllithium was added in an amount of 0.05 to 0.20% by weight based on the total amount of the used monomers to start the reaction. 0.1 to 0.30% by weight, butadiene is immediately added, and the reaction is further continued. At this time, the maximum temperature of the reaction is adjusted to 80 to 110 ° C. After the completion of the reaction, silicon tetrachloride was added to n-butyllithium in a concentration of 0.1%.
The reaction is performed by adding 5 to 1.5 equivalents. After completion of the reaction, a stabilizer is added and the solvent is separated to obtain a desired copolymer rubber.

Since the polybutadiene rubber used in the present invention is not particularly limited except for the solution viscosity, a so-called cis-polybutadiene rubber obtained by anionic polymerization using the same organolithium catalyst as described above, or cobalt,
High cis polybutadiene rubber obtained from a transition metal compound such as nickel or titanium or a rare earth metal compound such as neodymium or lanthanum can be used. The method for producing the polybutadiene rubber is not particularly limited, and it can be produced by a known production method such as a continuous polymerization method, a batch polymerization method, and a method using a coupling agent.

The method of blending the butadiene-styrene copolymer rubber with the polybutadiene rubber may be such that the respective rubbers are blended when the rubber-modified styrene resin is produced or dissolved in a styrene monomer or the like. It may be blended at the time of production of the polymer in a state. The method for obtaining the rubber-modified styrenic resin of the present invention may be a known method as long as the present invention is satisfied, and in particular, a bulk polymerization method and a bulk-suspension polymerization method may be used. preferable.

Hereinafter, embodiments of the bulk polymerization method and the bulk-suspension polymerization method will be described. In general, in the bulk polymerization method, a rubber-like polymer is dissolved in a styrene-based monomer, and if necessary, a monomer such as acrylonitrile, which can be copolymerized, further, a diluent such as toluene or ethylbenzene, a liquid paraffin. Lubricants such as oil and mineral oil, antioxidants,
A chain transfer agent such as a mercaptan or an α-methylstyrene dimer is added, and in the case of no catalyst, heat polymerization is usually performed at 95 to 200 ° C., and in catalyst polymerization, generally at a lower temperature, that is, 60 to 150 ° C. At ℃, the polymerization operation is continued until the polymerization of styrene is substantially completed.

In the case of catalytic polymerization, 1,1 is used as an initiator.
-Bis (t-butylperoxy) cyclohexane, 1,
Peroxyketals such as 1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane;
t-butyl peroxide, 2,5-dimethyl-2,5
Dialkyl peroxides such as di- (t-butylperoxy) dicumyl peroxide; diacyl peroxides such as benzoyl peroxide, n-toluyl peroxide, lauroyl peroxide; dimyristyl peroxy dicarbonate, diisopropyl peroxy Peroxydicarbonates such as dicarbonate; t
Peroxyesters such as -butylperoxyisopropyl carbonate, t-butylperoxyacetate, di-tert-butylperoxyisophthalate, di-tert-butylperoxybenzoate; ketone peroxides such as cyclohexanone peroxide and methyl ethyl ketone peroxide Oxides; hydroperoxides such as p-mentha hydroperoxide, t-butyl hydroperoxide and cumene hydroperoxide; and azo compounds such as azobisisobutyronitrile and azobiscyclohexanecarbonitrile. These are used alone or in combination of two or more.

If necessary, chain transfer agents such as mercaptans, α-methylstyrene dimer, and terpinolene can be used. In the bulk polymerization, a well-known internal lubricant such as liquid paraffin is often added in an amount of 1 to 5 parts by weight based on 100 parts by weight of the polymer. After the polymerization is completed, a small amount (1 to 20)
%) Of the unreacted monomer, it is desirable to remove the monomer by a known method, for example, a method of removing under reduced pressure or an extruder designed for the purpose of removing volatile components. .

The stirring during the bulk polymerization is carried out as necessary. After the conversion of the monomer into the polymer, that is, the conversion of the monomer reaches 30 to 40%, the stirring is eased. It is desirable. Excessive stirring may reduce the strength of the resulting polymer. If necessary, the polymerization may be carried out in the presence of a small amount of a diluent such as toluene or ethylbenzene, and after the polymerization, these diluents may be removed by heating together with the unreacted monomer.

In the bulk-suspension polymerization method, the first half of the reaction is first performed in a bulk state, and the second half of the reaction is performed in a suspended state. That is, the monomer solution of the rubber-like polymer is subjected to heat polymerization or catalyst addition polymerization in the absence of a catalyst in the same manner as in the case of the bulk polymerization, and usually 50% or less of the monomer, preferably 20 to 40%. Is partially polymerized. This is the bulk polymerization in the first half.

Next, the partially polymerized mixture is dispersed under stirring in an aqueous medium in the presence of a suspension stabilizer or both of a suspension stabilizer and a surfactant, and the latter half of the reaction is completed by suspension polymerization. It is washed, dried, pelletized or powdered if necessary, and put to practical use. In addition to the above, these methods can be modified and improved to obtain useful impact-resistant styrene resins by known methods.

An organic polysiloxane such as polydimethylsiloxane may be added to the composition of the present invention. In this case, polymerization may be performed by adding an organic polysiloxane to the styrene-based monomer, or may be mixed using an extruder or the like. Further, together with the specific copolymer rubber and polybutadiene rubber in the present invention, when a part of styrene forming the impact-resistant styrene resin is replaced by a radical copolymerizable monomer with styrene other than styrene, such styrene The other copolymerizable monomers are used in an amount of 50% by weight or less based on all monomers including styrene.

The copolymerizable monomer other than styrene is selected from acrylonitrile, methyl methacrylate, maleic anhydride, and monovinyl aromatic hydrocarbons such as α-methylstyrene, vinyltoluene and vinylethylbenzene. One or more monomers are used.

The impact-resistant styrene resin of the present invention can be used as a variety of practically useful products by processing methods such as injection molding and extrusion molding. Furthermore, when processing, if necessary, antioxidants, ultraviolet absorbers, flame retardants, lubricants, release agents,
Fillers, etc., and other thermoplastic resins such as general-purpose polystyrene, methacrylic resin, polyphenylene ether,
It may be used by mixing with polycarbonate, styrene-butadiene block copolymer resin, methyl methacrylate-styrene copolymer resin, maleic anhydride-styrene copolymer resin, or the like.

[0039]

EXAMPLES Some examples are given below to illustrate specific embodiments of the present invention, which are intended to more specifically explain the gist of the present invention and are not intended to limit the present invention. is not.

(1) Butadiene-styrene copolymer sample:
The butadiene-styrene copolymer (Sample A) used in the present invention was obtained by the following method. Internal volume 10L
The autoclave was washed, dried and purged with nitrogen. 5.2 kg of cyclohexane and 9.4 g of tetrahydrofuran, which had been purified and dried in advance, were added, and then 112 g of dried styrene.
Was added. Next, the temperature of the monomer mixture was raised to 72 ° C., and 6.4 g of a 10% by weight cyclohexane solution of n-butyllithium was added to start the reaction.

After completion of the reaction, 14.4 g of a 10% by weight solution of n-butyllithium in cyclohexane and 688 g of dried butadiene were subsequently added to restart the reaction. After completion of the reaction, 1.24 g of silicon tetrachloride was added, followed by 30 minutes. Reacted. 2,6-di- as a stabilizer was added to the obtained polymer solution.
t-butyl-4-methylphenol (BHT)
PHR was added and the solvent was removed by heating. Hereinafter, Examples B and C, Comparative Example D, and the same method under the conditions shown in Tables 1 and 2
A copolymer of E and F was obtained. As the sample G of the comparative example, a commercially available rubber shown in Table 3 was used.

(2) Polybutadiene sample: H shown in Table 3
Commercially available polybutadiene rubbers of I, J and K were used as Examples and Comparative Examples. The bound styrene content, Mooney viscosity, and solution viscosity of each rubber sample were measured by the methods described above.

(3) Production of impact-resistant styrene resin: Table 1
Using each of the rubber samples Nos. 1 to 3, an impact-resistant styrene resin was obtained by a bulk polymerization method described below.

That is, various rubbery polymers shown in Tables 1 to 3 were prepared with the compositions shown in Table 4 and uniformly dissolved. This was transferred to a reactor equipped with a stirrer.
Add 1-bis (t-butylperoxy) cyclohexane and add 105 ° C. for 3 hours, 135 ° C. for 2 hours, 160 ° C.
For 2 hours. During the reaction, the number of agitation was controlled in order to adjust the average particle size of the rubbery particle phase.

After unreacted substances were removed from the obtained polymer at 230 ° C. under reduced pressure, it was pelletized by an extruder. The average particle diameter was measured using a Coulter counter and expressed as a 50% median diameter. The Izod impact strength was measured using a 3.2 mm thick test piece prepared by compression molding.
Measured according to 7110. Gloss is JIS K-874
According to No. 1, the measurement was performed using an injection molded test piece. The results are shown in Tables 4 to 6.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

[0049]

[Table 4]

[0050]

[Table 5]

[0051]

[Table 6]

As is clear from the results of Examples 1, 2 and 3 in Table 4, when the rubbery polymer of the present invention was used at a specific ratio to obtain an impact-resistant styrenic resin, the impact strength and gloss were high. It can be seen that a resin excellent in is obtained.

On the other hand, as is apparent from the results of Comparative Examples 1 and 2, when the resin is used in a ratio other than that of the present invention, a resin having poor gloss or impact strength can be obtained. Further, from the results of Examples 4 to 9 and Comparative Examples 3 to 7 in Tables 5 and 6, it is understood that when the properties of the rubbery polymer used are other than the present invention, the balance between the impact strength and the gloss is poor.

[0054]

The rubber-modified impact-resistant resin composition of the present invention has excellent gloss and sufficient impact resistance, and is particularly useful in fields where both appearance and impact resistance are required. It can be used in a wider range, and the effect of the invention is great.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08F 279/02 C08L 25/04 C08L 51/04

Claims (2)

(57) [Claims] (A) (a) Bound styrene content (TS)
Is 2 to 15% by weight, and (b) the solution viscosity (SV) is 5 to 50.
Centipoise (cps), (c) Mooney viscosity (ML)
20-150, (d) ML / SV ratio is 3-7,
(E) A butadiene-styrene copolymer in which the relationship among TS, SV, and ML satisfies the following formula (1): -50 ≦ [(ML × 2) − (SV × TS)] ≦ 50 (1) The polymer rubber and (B) a polybutadiene rubber having a solution viscosity of 10 to 100 centipoise are mixed in a weight ratio of the butadiene-styrene copolymer rubber and the polybutadiene rubber of 95: 5 to 30: 7.
A rubber-modified impact-resistant styrenic resin composition containing 3 to 25% by weight of a rubbery polymer contained in a range of 0. 2. (A) (a) Bound styrene content (TS)
Is 2 to 15% by weight, and (b) the solution viscosity (SV) is 5 to 50.
Centipoise (cps), (c) Mooney viscosity (ML)
20-150, (d) ML / SV ratio is 3-7,
(E) A butadiene-styrene copolymer in which the relationship among TS, SV, and ML satisfies the following equation (1): -50 ≦ [(ML × 2) − (SV × TS)] ≦ 50 (1) The polymer rubber and (B) a polybutadiene rubber having a solution viscosity of 10 to 100 centipoise are mixed in a weight ratio of the butadiene-styrene copolymer rubber and the polybutadiene rubber of 95: 5 to 30: 7.
0 to 3 to 25% by weight of the rubbery polymer contained in the range;
Rubber modified impact resistance characterized by subjecting 97 to 75% by weight of a mixture of a styrene monomer or a monomer copolymerizable with a styrene monomer to bulk polymerization, bulk suspension polymerization or solution polymerization. A method for producing a water-soluble styrenic resin composition.