JPS6361341B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermoplastic resin composition that has excellent impact resistance and gloss. The present invention also relates to a thermoplastic resin composition containing 20 to 80% by weight of a specific impact-resistant styrenic resin. Thermoplastic resins are generally used in a wide range of applications due to their excellent moldability during processing.
In certain fields of application, the use of only one type of thermoplastic resin may not allow its various properties to fully satisfy desired conditions. Therefore, as a method to overcome such dissatisfaction, it is often effective to modify the resin composition to have almost the desired properties by blending it with other thermoplastic resins. Regarding the above, typical properties required of thermoplastic resins include impact resistance and gloss.
Having both of these properties is often important for many applications. For example, polystyrene has extremely high gloss, but has poor impact resistance and cannot be used in practical applications. It has been modified to the extent that it can withstand it. An object of the present invention is to obtain a thermoplastic resin composition that is excellent in both impact resistance and gloss. In order to achieve the above object, we will discuss an impact-resistant styrenic resin that is a constituent element of the thermoplastic resin composition and a thermoplastic resin that can be used to blend the impact-resistant styrenic resin and which can particularly achieve the object of the present invention. Various considerations were made. As a result, we discovered the following new facts. (a) In the case of a composition of an impact-resistant styrenic resin and another thermoplastic resin, if the impact-resistant styrenic resin has excellent impact strength, the impact strength of the composition is generally excellent. However, the use of high impact styrenic resins with certain polybutadiene rubbers improves this further. (b) In addition, regarding the gloss in the above, when the impact-resistant styrene resin has excellent gloss, the gloss of the composition is also generally excellent, but when a certain polybutadiene rubber is used, A further improvement is achieved through the use of high impact styrenic resins. Thermoplastic resins that are blended with impact-resistant styrenic resins using the specific polybutadiene rubber mentioned above include MMA resins (methyl methacrylate resins), polyphenylene ether resins, styrene resins, etc.
Butadiene block copolymer resins were primarily selected and were found to provide compositions with excellent gloss and impact resistance, leading to the present invention. That is, in the present invention, the polybutadiene rubber content is 5
~25% by weight, and the average particle size of the rubber particle phase dispersed in the resin is 0.2~5μ, and the polybutadiene rubber used is
1.2 vinyl content 15-35%, 1.4 cis content 20-85%
and Mooney viscosity (ML ₁₊₄ ) 20~100, 25℃
5 wt% styrene solution viscosity (SV) measured at 15
This is a thermoplastic resin composition characterized by containing 20 to 80% by weight of an impact-resistant styrenic resin which is a polybutadiene rubber having a relationship of 0.5ML ₁₊₄ ≦SV≦1.0ML ₁₊₄ at ~50 cps. The present invention is characterized by the discovery that this can be achieved for the first time by using a specific polybutadiene rubber as the impact-resistant styrene resin that is a component of the composition. This is a very special polybutadiene rubber compared to those commonly available on the market. That is, considering the microstructure of the polybutadiene rubber used in the present invention, it is generally possible to polymerize with an organolithium-based catalyst, but commercially available polybutadiene rubber using an organolithium-based catalyst has an SV>3.0ML _{1 +4} is the majority, whereas the polybutadiene rubber used in the present invention is
0.5ML ₁₊₄ ≦SV≦1.0ML ₁₊₄ , and the SV is extremely low considering the Mooney viscosity.
For this reason, the polymerization technology for polybutadiene rubber requires some ingenuity, but it has extremely industrial advantages in that it is convenient for stirring and transporting the rubber polymerization solution during rubber production, and there is little cold flow during rubber storage. are doing. In addition, when producing impact-resistant styrene-based resins, the solution viscosity when dissolved in styrene is extremely low, which not only allows for excellent control over the rubber particle size, but also has industrial advantages in that it is convenient for stirring and transportation. It also has some aspects. In addition, in the present invention, the impact resistance was mainly determined by measuring the Izot impact strength, but even when the Izot impact strength of the impact-resistant styrenic resin is low, the Izot impact strength of the composition of the present invention is The strength is greatly improved.
These tendencies are particularly noticeable in thermoplastic compositions with polyphenylene ether resins. The present invention will be explained in more detail below. First, the impact-resistant styrenic resin, which is a component of the present invention, will be explained. The specific polybutadiene rubber used in the impact-resistant styrenic resin can be obtained by solution polymerization using an organolithium compound as a catalyst. As organic lithium, n-butyllithium, sec
-Organic monolithium such as butyllithium is common, but as shown in JP-A-57-40513, 1.2-dilithio-1.2-diphenylethane, 1.4
Examples include a mixture of a polyfunctional organolithium such as -dilithio-2-ethylcyclohexane and an organomonolithium, or a reaction product containing both an organomonolithium and a polyvinyl aromatic compound (for example, divinylbenzene). The specific polybutadiene rubber used in the present invention is
1.2 vinyl content is 15-35% and cis 1.4 content is
It is 20-80%. If it is outside this range, the impact resistance of the thermoplastic resin composition of the present invention will be poor. The method for producing polybutadiene rubber having such a specific microstructure may be any conventionally known method as long as it produces the above structure, but as a specific method, for example, dimethyl ether is added to the polymerization system. , ethers such as diethyl ether and tetrahydrofuran, thioethers such as dimethyl sulfide and diethyl sulfide, dimethylethylamine, triethylamine,
Examples include a method of polymerizing by adding a polar compound such as amines such as tri-n-propylamine. Even though vinyl bonds are uniformly distributed in the molecular chain,
As shown in Japanese Patent Publication No. 48-875, it may change gradually along the molecular chain, or it may be linked in blocks, with a total of 15~
It is sufficient if the content is 35% by weight. The polybutadiene rubber used for the impact-resistant styrenic resin has a Mooney viscosity (ML ₁₊₄ ) of 20 to 100, preferably 25 to 60, and a 5 wt% styrene solution viscosity (SV) of 15 to 50 cps, measured at 25°C. Preferably it is 20 to about 25 cps, and is in the range of 0.5ML ₁₊₄ ≦SV≦1.0ML ₁₊₄ . If the Mooney viscosity is less than 20, the impact resistance of the resulting thermoplastic resin composition will be poor, and if the Mooney viscosity is less than 100.
If it exceeds this amount, it will take time to dissolve the rubber in styrene, and furthermore, drying during rubber production will be difficult, which is industrially disadvantageous. In addition, if the SV is less than 15 cps, the impact resistance of the resulting thermoplastic resin composition will be poor, and if the SV exceeds 50 cps,
In particular, it becomes difficult to control the rubber particle phase to a size of about 0.2 to 1.7 microns, and at the same time, the gloss is poor. What is surprising here is that when the polybutadiene rubber used is 0.5ML ₁₊₄ ≦SV≦1.0ML ₁₊₄ and the dispersed rubber particle phase of the obtained impact-resistant styrenic resin is 0.2 to 1.7μ, SV20 It has been found that when polybutadiene rubber of ~25 cps is used, the final thermoplastic resin composition has a particularly excellent balance between gloss and impact resistance. In addition, for 0.5ML ₁₊₄ > SV, the dispersed rubber particle phase is 0.2
It becomes difficult to stably control the thickness to about 1.7μ, and the resulting thermoplastic resin has poor impact resistance. When SV>1.0ML ₁₊₄ , the thermoplastic resin composition becomes particularly poor in gloss. The impact-resistant styrenic resin constituting the present invention is
The content of specific polybutadiene rubber is 5-25% by weight, preferably 8-20% by weight. The reason why the above range is preferable is related to the fact that the polybutadiene rubber used is a specific rubber of 0.5ML ₁₊₄ ≦SV≦1.0ML ₁₊₄ , but also in the final thermoplastic resin composition. This is because, when the polybutadiene rubber content contained in the rubber is constant, the impact resistance varies depending on the rubber content in the impact resistant styrene resin used. For example, when the polybutadiene rubber content in the thermoplastic resin composition is constant at 3% by weight, the rubber 6
Weight % impact resistant styrenic resin/polyphenylene ether (50/50) and rubber 12 weight % impact resistant styrenic resin/polyphenylene ether (25/50)
75), the latter has better impact resistance. If the rubber content in the impact-resistant styrenic resin is less than 5% by weight, the impact resistance of the resulting thermoplastic composition will be insufficient, and if the rubber content exceeds 25% by weight, during the production of the impact-resistant styrenic resin,
The solution viscosity is high, making it difficult to control the rubber particle size. As mentioned above, the polybutadiene rubber used for the impact-resistant styrene resin that constitutes the present invention has a very special relationship between ML ₁₊₄ and SV, and also has an extremely low SV. requires some ingenuity. A specific method is, for example, a method in which a small amount of divinylbenzene is added to the polymerization system (Japanese Patent Publication No. 39-1989).
17074), or coupling the living polymer with a polyfunctional coupling agent such as halides such as silicon tetrachloride, methyltrichlorosilane, and carbon tetrachloride, and diesters such as diethyl adipate [for example, Journal of
Polymer Science Part A, Vol3, 93-103(65),
[UK Patent No. 1,223,079, etc.] is also useful. When the above-mentioned living polymer is coupled with a polyfunctional coupling agent, the living polymer can be polymerized by simply using organic monolithium such as n-butyllithium, or by polymerizing organic dilithium such as 1.2-dilithio-1.2-diphenylethane with organic dilithium. A method of polymerizing in a mixture with,
There is a method in which a reaction product containing both organic monolithium and a polyvinyl aromatic compound (for example, divinylbenzene) is polymerized. Although the specific polybutadiene rubber used in the present invention can be produced by this method, other conventionally known methods may be used as long as the above range is satisfied. The average particle diameter of the rubber particle phase dispersed in the impact-resistant styrenic resin constituting the present invention is in the range of 0.2 to 5 microns, preferably 0.2 to 1.7 microns. If the rubber particle size is less than 0.2μ, the impact resistance of the thermoplastic resin composition will be insufficient, and if it exceeds 5μ, the gloss will be poor. The impact-resistant styrenic resin of the present invention may be obtained by any known method as long as it satisfies the requirements of the present invention, but particularly bulk polymerization and bulk-suspension polymerization may be used. preferable. Hereinafter, embodiments of the bulk polymerization method and the bulk-suspension polymerization method will be described. Generally, in bulk polymerization, a specific polybutadiene rubber is dissolved in styrene and polymerized by heating, usually at 95 to 200°C in the case of no catalyst, while in catalytic polymerization or radiation polymerization, it is generally carried out at a lower temperature, i.e., 20 to 150°C. The polymerization operation is continued until the polymerization of styrene is substantially completed. During this bulk polymerization, known internal lubricants, such as liquid paraffin, are often added to the polymer.
It is added in an amount of 1 to 5 parts by weight per 100 parts by weight. After completion of the polymerization, if the resulting polymer contains a small amount (1-5%) of unreacted styrene, such styrene is removed by known methods such as vacuum removal or extrusion equipment designed for the purpose of removing volatiles. It is desirable to remove it by methods such as Stirring during such bulk polymerization is performed as necessary, but it is desirable to stop or moderate the stirring after the conversion rate of styrene into a polymer, that is, the polymerization rate of styrene has progressed to 80% or more. . Excessive stirring may reduce the strength of the resulting polymer.
Further, if necessary, polymerization may be carried out in the presence of a small amount of a diluent such as toluene or ethylbenzene, and after the completion of the polymerization, these diluents may be removed by heating together with unreacted styrene. Bulk suspension combined polymerization is also useful in producing the high impact styrenic resins that are a component of this invention. In this method, first, the first half of the reaction is carried out in a bulk state, and the second half of the reaction is carried out in a suspended state. That is,
A styrene solution of the specific butadiene rubber of the present invention is subjected to heat polymerization or catalyst addition polymerization in the same manner as in the previous bulk polymerization, or by irradiation polymerization.
Usually less than 50% of the styrene is partially polymerized, preferably up to 10-40%. This is the first stage of bulk polymerization. This partially polymerized mixture is then dispersed under stirring in an aqueous medium in the presence of a suspension stabilizer or both a suspension stabilizer and a surfactant, and the second half of the reaction is completed by suspension polymerization, and finally Wash, dry,
If necessary, it is made into pellets or powder for practical use. In addition to the above, useful impact-resistant styrenic resins can be obtained by conventionally known methods that are modified or improved from these methods. Further, a part of the styrene that forms the impact-resistant styrenic resin together with the specific polybutadiene in the present invention may be replaced with a monomer capable of radical copolymerization called styrene other than styrene. Such copolymerizable monomers other than styrene are used in an amount of 50% by weight or less based on the total monomers containing styrene. Such copolymerizable monomers other than styrene include α-methylstyrene, vinyltoluene, vinylethylbenzene, vinylxylene,
Monovinyl aromatic hydrocarbons such as vinylnaphthalene, conjugated dienes such as butadiene and isoprene,
Alternatively, one or more monomers selected from acrylonitrile, methyl methacrylate, etc. are used. Next, the thermoplastic resin blended with the impact-resistant styrenic resin in the present invention will be described. The thermoplastic resin is selected from MMA resin, polyphenylene ether resin, and styrene-butadiene block copolymer resin. The MMA resin is a resin obtained by polymerizing or copolymerizing at least 50% of methyl methacrylate monomer and other olefinic vinyl monomers. The general formula for polyphenylene ether resin is (In the formula, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ are monovalent groups such as the same or different alkyl groups having 1 to 4 carbon atoms, excluding tert-butyl groups, allyl groups, halogens, hydrogen, etc.) (R ₅ and R ₆ are not hydrogen at the same time) as a repeating unit, and the constituent units are () or () and (), a homopolymer or
It is a copolymer. The styrene-butadiene block copolymer resin is a copolymer consisting of at least one polybutadiene block and at least two polystyrene blocks, and the styrene content is generally 50 to 90% by weight. The above-mentioned various thermoplastic resins are used by blending 20 to 80% by weight with the impact-resistant styrenic resin that is a component of the present invention. If it is less than 20% by weight, the various plastic resins described above will have poor properties other than gloss and impact resistance, and if it exceeds 80% by weight, the effect of improving impact resistance and gloss will be poor. In the thermoplastic resin composition of the present invention, in particular,
In a blend of a polyphenylene ether resin and an impact-resistant styrenic resin, a particularly effective thermoplastic resin composition is obtained when the rubber particle size in the styrenic resin is as low as 0.2 to 1.7 μm. The thermoplastic resin composition 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, during processing, antioxidants, ultraviolet absorbers, lubricants, mold release agents, fillers, and other thermoplastic resins may be mixed as necessary. As explained above, the present invention is a thermoplastic resin composition that is excellent in both gloss and impact resistance, and its application range is wide and the industrial significance of the present invention is great. Some examples are shown below to illustrate specific embodiments of the present invention. Example 1 The polybutadiene rubber of Example B in Table 1 was polymerized by the method shown below. That is, an autoclave with an internal volume of 10 and a stirring device and a jacket was washed and dried, and after purging with nitrogen, 100 parts by weight of butadiene monomer purified and dried in advance and n
- Add 700 parts by weight of hexane, add 0.23 parts by weight of a 10% by weight n-hexane solution of n-butyllithium in terms of n-butyllithium, and further add 0.17 parts by weight of tetrahydrofuran as a 1.2 vinyl modifier, and heat to 70°C. Polymerization was started. After 1 hour of polymerization, silicon tetrachloride was added as a coupling agent.
0.122 parts by weight was added and reacted for 1 hour. Example B
of polybutadiene rubber was obtained. Furthermore, Example C,
The polybutadiene rubbers of D, E, and Comparative Examples A and F were polymerized in the same manner as in Example B, except that the amounts of catalyst and coupling agent were changed. Table 1 shows the properties of the obtained polybutadiene rubber. The 5 weight % styrene solution viscosity was measured at 25° C. using a Canon Fuenske viscometer. The microstructure was determined by the Morello method [La.chimica EL′industria, 41, 758 (1959)] using an infrared spectrophotometer.
]. Using each rubber in Table 1, impact-resistant styrenic resins were obtained by the bulk polymerization method described below. That is, 9.6 parts by weight of each of the various rubbers shown in Table 1 were uniformly dissolved in 90.4 parts by weight of styrene and 10 parts by weight of toluene. This was transferred to a reactor equipped with a stirring device and a jacket, and 1 x 10 ^-4 mol of styrene was added per 1 mol of styrene.
Add tert-butyl peroxide and heat at 110°C.
The reaction was carried out at 140°C for 5 hours and at 160°C for 2 hours. During the reaction, the average particle size of the rubber particle phase is about 1.1~1.3μ
The number of stirring was controlled so that the After removing unreacted substances from the resulting polymer at 230° C. under reduced pressure, 0.5 parts by weight of BHT was added per 100 parts by weight of the polymer, and the mixture was pelletized using an extruder. The average particle size was measured using a Coulter counter and expressed as a 50% median diameter. MI (melt index)
was measured in accordance with ASTM D1238 under condition G (200°C x 5 kg). Table 1 shows the properties of the impact-resistant styrenic resin obtained.
Shown below. The physical properties of a 50:50 blend of the above resin and polyphenylene ether [poly(2.6-dimethyl-1.4-phenylene ether, degree of polymerization 120)] were measured. Measurements were made in accordance with JIS K6871 using a flat plate approximately 3 mm in diameter.Gloss was measured by injection molding in a 150 mm x 150 mm, 2 mm thick mold with a single pin gate, and the average value of the gloss at the gate and the opposite side of the gate. was measured in accordance with JIS K8741.The obtained results are shown in Table 1.From Table 1, Example C has the best balance between gloss and impact resistance, Comparative Example A has poor impact resistance, and Comparative Example It can be seen that in F, both the gloss is inferior.

[Table] Example 2 Ratio of 5 wt% styrene solution viscosity (SV) and Mooney viscosity (ML ₁₊₄ ) as shown in Table 2 SV/
Four types of polybutadiene rubbers with different ML ₁₊₄ were polymerized. The catalyst used was n-butyllithium, and the coupling agent was silicon tetrachloride. Polymerization was carried out in the same manner as in Example 1, except that the amounts used of both were changed. Impact-resistant styrenic resins having a rubber content of 18% by weight and a rubber particle diameter of about 0.9 μm were obtained by bulk suspension polymerization using the above four types of polybutadiene rubbers. That is, 18 parts by weight of each of the various rubbers shown in Table 2 were uniformly dissolved in 82 parts by weight of styrene. Transfer this to a reactor with a stirring device and jacket,
0.06 parts by weight of tert-dodecyl mercaptan was added, and the solution was heated without catalyst at 120°C for 5 hours with stirring to form a solution in which about 35% of styrene was polymerized.
Per 100 parts by weight of the solution, 0.3 parts by weight of trisnonyl phenyl phosphorite and 0.1 parts by weight of di-tert-butyl peroxide were added. On the other hand, 0.2 parts by weight of a suspension stabilizer polyvinyl alcohol and 0.75 parts by weight of a surfactant sodium dodecylbenzenesulfonate were dissolved in 150 parts by weight of water, and 100 parts by weight of the above-mentioned partial polymer was suspended; This suspension mixture was heated at 120°C for 6 hours with stirring.
Next, the polymerization of styrene was substantially completed by heating at 130° C. for 3 hours to obtain a suspended particle-like impact-resistant styrenic resin. This was separated from the reaction mixture by centrifugation, washed with warm water and air dried. The rubber particle diameter was adjusted to about 0.9μ by adjusting the rotation speed of the stirrer of the reactor. The properties of the resulting impact-resistant styrenic resin were measured in the same manner as in Example 1. The results are shown in Table 2. The above resin and polyphenylene ether [poly(2.6-dimethyl-1.4-phenylene) ether,
A 50:50 blend with a polymerization degree of 120] was measured in the same manner as in Example 1. Table 2 shows the results.
Shown below. From Table 2, Examples H and I are excellent in both gloss and impact resistance, Comparative Example G is poor in impact resistance, and Comparative Example J is particularly poor in gloss.

[Table] Example 3 The polybutadiene rubber used in the present invention shown in Table 3 was polymerized in the same manner as in Example 1. However, in Example 1, n-butyllithium was used as a catalyst, but in Example 3, a reaction product containing both n-butyllithium and divinylbenzene prepared by the method shown below was used as a catalyst. That is, 13.5 parts by weight of n-butyllithium, 4.11 parts by weight of divinylbenzene, 100 parts by weight of butadiene monomer.
Add parts by weight to 700 parts by weight of n-hexane and heat at 70°C.
The mixture was reacted for 40 minutes and used as a catalyst. When this adjusted catalyst was added to the polymerization system, the amount was expressed in terms of n-butyllithium. Commercially available divinylbenzene was used. This product is a mixture (approximately 57%) containing divinylbenzene isomers;
The remainder is ethylbenzene and diethylbenzene. The amount of catalyst used was 0.25 parts by weight in terms of n-butyllithium per 100 parts by weight of butadiene monomer, and the coupling agent silicon tetrachloride was 0.11 parts by weight.
Parts by weight were used. The properties of the obtained polybutadiene rubber are shown in Example 1.
Table 3 shows the characteristics measured using the same method as above. Using the above polybutadiene rubber, bulk polymerization was carried out in the same manner as in Example 1 to obtain an impact-resistant styrenic resin. The rubber content was 13% by weight, and the rubber particle size was determined by adjusting the rotation speed of the stirrer in the reactor.
Adjusted to 3.0μ, 1.5μ, and 0.4μ. The physical properties of the resulting impact resistant styrenic resin were measured in the same manner as in Example 1 and are shown in Table 3. In addition, a 40:60 blend of each of the above impact-resistant styrene resins and polyphenylene ether [poly(2,6-dimethyl-1,4-phenylene) ether, degree of polymerization 120] was measured in the same manner as in Example 1, and the table below Shown in 3. Table 3 shows that even when the impact resistance of the impact resistant styrenic resin is poor as in Example M, the composition of the present invention exhibits excellent impact resistance. Further, it can be seen that the impact resistance of Examples L and M is superior to that of Example K.

[Table] Example 4 Using the polybutadiene rubber of Example C of Example 1, an impact-resistant styrene resin with a rubber particle size of approximately 1.2μ and a rubber content of 12% by weight (equivalent to Example C) and the rubber content A sample containing 6% by weight was obtained in the same manner as in Example 1. A thermoplastic resin composition was obtained by blending the above two types of impact-resistant styrenic resins with polyphenylene ether [poly(2.6-dimethyl-1.4-phenylene) ether, degree of polymerization 120]. The blend ratio was determined so that the rubber content was 3% by weight.
That is, 25:75 in Example N of Table 4, and 25:75 in Example O.
It was set at 50:50. The properties of the resulting composition were measured in the same manner as in Example 1 and are shown in Table 4. Table 4 shows that Example N has better impact resistance than Example O.

【table】

[Table] Example 5 Using the polybutadiene rubber of Example H of Example 2 and Comparative Example J and impact-resistant styrenic resin using the same, a 50:50 ratio with various thermoplastic resins shown below was used.
The properties of the thermoplastic resin composition were measured in the same manner as in Example 1. The MMA resin used in Example P and Comparative Example Q is a copolymer of 60% methyl methacrylate and 40% styrene, and has an MI (230° C., 3.8 kg) of 12. The styrene-butadiene block copolymer resin used in Example R and Comparative Example S is a styrene-butadiene-styrene type polymer, with a styrene content of 75% by weight and an MI (200° C., 5 kg) of 10. From Table 5, it can be seen that Example P and Example R have excellent impact resistance.

【table】

Claims (1)

[Claims] 1 The polybutadiene content is 5 to 25% by weight,
The average particle size of the rubber particle phase dispersed in the resin is
An impact-resistant styrenic resin having a thickness of 0.2 to 5μ,
The polybutadiene used has a 1,2 vinyl content of 15~
35%, with a 1,4-cis content of 20-85%, and a Mooney viscosity (ML ₁₊₄ ) of 20-100, with a 5 wt.% styrene solution viscosity (SV) of 15-50 cps measured at 25°C.
0.5ML _{1+4 ≦} SV≦1.0ML 20~
80% by weight and thermoplastic resin 80 selected from methyl methacrylate resin, polyphenylene ether resin, and styrene-butadiene block copolymer resin.
A thermoplastic resin composition characterized by comprising ~20% by weight.