JPH01279943A - Styrene resin composition - Google Patents

Abstract

PURPOSE:To obtain a styrene resin composition improved in gloss and impact resistance by copolymerizing a styrene with a specified wholly blocked styrene/ butadiene block copolymer. CONSTITUTION:92-60wt.% styrene component comprising styrene and, optionally, at most 50wt.% monomer copolymerizable therewith is prepolymerized with 8-40wt.% wholly blocked styrene/butadiene block copolymer of a content of repeating styrene units of 10-50wt.%, an MW of 80,000-300,000 and a weight-average MW of the blocked PS of 15,000-150,000 at 70-150 deg.C in the presence of an MW modifier and, optionally, a polymerization catalyst. The product of prepolymerization is then suspension-polymerized in the presence of a suspending agent, and the obtained product is dried and pelletized to obtain the title composition of a rubber particle diameter of 0.1-1.8mum and an MW of the matrix of 100,000-300,000.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a styrenic resin composition, and more particularly, ii.
L, < has excellent gloss and impact resistance and J(
The present invention also relates to a rubber-modified polystyrene resin composition which has excellent balance and can be suitably used in the fields of home appliances, OA equipment, various sheets, etc.

[Prior art and its problems] Conventionally, polystyrene polymers have been produced using a method of mechanically mixing unvulcanized rubber and polystyrene to improve their brittleness, or a method of mechanically mixing polystyrene with a polymerization system. has been applied. However, in recent years, in fields where impact resistance and surface gloss are required, these methods have not been able to provide sufficient results.

For example, JP-A-50-157493, JP-A-50-157493,
In the methods described in Japanese Patent Publication No. 4-19031 and Japanese Patent Publication No. 54-37908, a styrene-butadiene blow 2 744 polymer having random properties is applied to the polymerization reaction, but in this case, the resulting resin composition There is a problem that the gloss of the object is not sufficient, and also,
In the method described in Publication No. 143415, a complete block copolymer is used, but because the molecular steepness of the block polystyrene is as low as 1,000 to 10,000, the resulting resin composition has low gloss. There was a problem.

The present invention has been made based on the above information, and its purpose is to provide rubber particles with a specific Y-diameter, a specific matrix molecular weight, and even more than conventional high-impact polystyrene. The object of the present invention is to provide a styrenic resin composition which is extremely advantageous in practical use, having excellent gloss, high impact resistance, and an excellent balance of these properties.

[Means for solving the problem] As a result of intensive 7α research, the researchers at Unfinished IJI have developed a solution obtained by copolymerizing styrenes and a completely block type styrene-butadiene block copolymer in a specific ratio. A styrenic resin composition having a specific rubber particle diameter F and a specific matrix molecule t1 is disclosed in this 9. The present inventors have discovered that the first objective of the invention can be achieved, and based on this knowledge, they have completed the present invention.

Namely, book 9! lJJ is (A) styrene 92-6
0 Tamaboshi%, (B) the content of styrene as a repeating unit is 10 to 50% by weight, and the molecular weight is so, ooo
It is within the range of ~30G, 000 and is in the block polystyrene category! 5 mo molecule r5 is 15,000 to 150.
000, a completely block type styrene-butadiene-based blown copolymer with a weight of 8 to 40% by weight and p%.
In addition, the rubber particle diameter is 0.1 to 1.81 Lm, and the matrix intermolecular size is sao, aaa to 3G0.
000 is provided.

The above-mentioned Japanese Patent Application Laid-open No. 50-15 introduced in the prior art section
According to the description in Publication No. 7493, a specific styrene-butadiene random copolymer having a gradually decreasing composition in which styrene-containing It: decreases continuously along the polymer density of the copolymer and styrene has excellent # resistance. ? However, it is possible to obtain #I impact resistant polystyrene compositions with hardness and weld appearance.

High impact polystyrene obtained from a complete block copolymer of styrene and butadiene has a low Izot impact strength. From these facts, it is clear that a styrenic resin composition with a well-balanced and excellent impact resistance and gloss can be obtained from a completely block type styrene-butadiene block copolymer as in the present invention.
＜It is orkikoto.

Furthermore, according to the description in JP-A No. 81-143415, a polystyrene resin is disclosed which has a block styrene part with a molecular weight ratio of 1.000 to 10,000 and has excellent gloss and #iW resistance. has been done. In the same publication, it is stated that the molecular weight ratio of this block styrene part is 10
,000, the resistance of polystyrene resin is #+1!
Considering that it has been disclosed that the sexual performance is extremely low, it is 1.
As in the present invention, both gloss and impact resistance can be obtained from a specific completely block type styrene-butadiene block copolymer in which the block polystyrene moiety has a molecular weight of 15,000 to 150,000. It is unexpected that excellent impact resistant resin compositions can be obtained.

Thus, the present invention, which is unexpected from the prior art, will be described in detail below.

-(A) Styrenes- The styrenes of the component (^) are styrene (A1) and a styrene-resistant material that can be co-polymerized with styrene, and can be copolymerized with styrene to form #i #IX-resistant styrene. The width body (A2) is capable of forming a styrene copolymer in which a part of the styrene repeating units in the styrene polymer forming the resin are replaced by repeating units other than the styrene.

However, 'It N1 body (A2) other than styrene
is more than 50% F in all monotonous substances including styrene, preferably 40! It is used in a range of 1Li% or less.

Examples of the non-styrene carrier (A2) include monovinyl aromatic hydrocarbons (A2a) such as α-methylstyrene, vinyltoluene, vinylethylbenzene, vinylxylene, and vinylnaphthalene, acrylonitrile, methyl methacrylate, and acrylic acid. Methyl, acrylic acid, methacrylic acid, maleic anhydride, phenylmaleimide, etc. can be mentioned, and one or more of these can be used in combination with styrene.

- (B) Completely block type styrene-butadiene block copolymer - Completely block type styrene-butadiene block copolymer (hereinafter referred to as SR block copolymer) of the component (B)
B) or simply (B). )as,
Completely block type styrene-1゜3-butadiene block #, polymer (hereinafter simply referred to as SB block copolymer B1)
Or it may be simply called (B1). ), a part of the styrene repeating unit in the SR block co-Touta combination B1) is a monovinyl aromatic hydrocarbon (
Bza) one in which a part of the 1,3-butadiene repeating unit in (B2) is replaced in the middle of the repeating position (B2),
1.Other diolefins (the) other than 3-butadiene
Those replaced with repeating units (B3), the above (B1
), a part of the styrene repeating unit and a part of the 1,3-butadiene repeating unit are respectively the above (Bza)
The 1 & repeat unit and the above (Baa) 1 & repeat unit (B4) can be used.

However, in (B2) and (B4) above, (lb a
) Use of repeating unit +lS= and use of (B3J) repeating middle in (B3) and (B4) above, monovinyl aromatic carbonized wood J repeating unit containing styrene all in and 1,3-butadiene, respectively. It is used in an amount of 50% by weight or less, preferably 401i% or less of the total weight of the conjugated diolefin repeating units contained.

In addition, monovinyl aromatic hydrocarbons other than styrene (
Specific examples of Bza) include those similar to (A2a) above, and one or more of these can be used.

Examples of diolefins other than #1,3-butadiene include isoprene and l.

3-Pentagene, ? , 3-dimethyl-1,3-phtadiene, 2-ethyl-1,3-bu')diene.

2.3-diethyl-1,3-butadiene, 2-phenyl-1,3-7'tadiene, 2.3-diphenyl-1,3
-butadiene, etc., and one or more of these can be used.

The completely block type styrene-butadiene block copolymer (B) in the present invention has a moderate repeating content of the styrenes [i.e., styrene and monovinyl aromatic carbonized wood 1 (Bza) other than styrene], The use of repeating units of styrenes, 1i1 1,3-butadiene (i.e., 1,3-butadiene and
- 10 to 50%, preferably 12 to 48
Use within the range of weight %.

If the acid content of the styrene repeating units is less than 10%, the resulting resin composition will have low gloss;
50rJ! If the content exceeds 1%, the impact resistance will decrease.

Moreover, the above-mentioned (B) according to the present invention is of a complete block type having substantially no random component, and if ([
1) If a resin composition having a random component as large as ei is used, the gloss of the resulting resin composition will be uneven.

Furthermore, the average molecular weight (%) of the above (B) is.

80.000~300.000. Preferably, 110
．． Q (within the range of 10 to 28G, 000, and if this molecule 1^ is less than 80.000, the impact resistance of the resulting resin composition will be low; on the other hand, 300
,000, fluidity during molding becomes insufficient.

In addition, in the above (B), the weight average molecular weight of the block portion formed by the styrene is 15, QQO ~ 15
0. QQ (1, preferably 20,000 to 140.0
However, if the average molecular weight of this block portion is less than 15,000, the resulting resin composition will have insufficient gloss;
If it exceeds 0, the impact resistance will be insufficient.

A preferred complete block type styrene-butadiene block copolymer (B) in the present invention is the above-mentioned SB block co-superior polymer BI).

This SR block coconjugate B1) can be produced, for example, as follows.

For example, JP-A-50-157493, JP-A-54-
The SB block was prepared according to the method of polymerizing styrene and 1,3-butadiene in an inert hydrocarbon solvent such as hexane, heptane, or benzene in the presence of an organolithium-based catalyst described in Publication No. 19031. A copolymer (B1) can be produced.

That is, 1,3-butadiene is mixed in the above inert hydrocarbon in the presence of organolithium -h, and this 1.
Once the entire amount of 3-butadiene has been polymerized, a predetermined amount of styrene is added to the polymerization system, and styrene is polymerized in blocks onto the active ends of the polybutadiene that has already been produced, resulting in the desired S
B block coconjugate B1] can be obtained.

Incidentally, specific examples of the above organolithium-based catalyst include propyllithium and n-butyllithium.

5ec-butyllithium, amyllithium, dilithiobutane, naphthyllithium, 1,4-dilithiobenzene, etc. are used.

Monostyrenic resin composition (copolymerization reaction) Book 9. The styrenic resin composition in light of the above (A)
It is obtained by copolymerizing styrene and (B) a completely block type styrene-butadiene block copolymer.

When carrying out copolymerization, the use of styrene, which is component (A), is the use of this component (A)! Nao and Said (B) I
When the total amount of the fully block type styrene-butadiene block co-assembly used as component A is 100 i1it%, it is 92 to 60 cm%, preferably 81 to 60 cm.
It is 62% by weight.

If the amount used exceeds 92% by weight, the impact resistance of the resulting styrenic resin composition decreases;
If it is less than that, the gloss will decrease and the fluidity during molding will decrease.

The copolymerization of component (B) and component (A) can be carried out using known polymerization methods, etc., similar to the polymerization reaction used to obtain component (B).

Such known polymerization methods include, for example, an emulsion polymerization method, a bulk polymerization method, a solution polymerization method, a suspension method, a combination multi-stage method such as a bulk-suspension two-stage polymerization method, and the like.

An example of a general method for producing the resin composition of the present invention using a bulk-suspension two-stage polymerization method is shown below.

First, a completely block type styrene-butadiene copolymer, which is a rubber-like elastic body, is added to styrene and, if necessary, heated to dissolve it.

It is preferable to perform this dissolution as uniformly as possible.

Next, the molecular weight adjustment w11's (
Or chain diameter! ! In the presence of a polymerization catalyst (or a bonding initiator) such as a lI agent) and an organic peroxide used as necessary, the polymerization degree of styrene is heated to 70 to 150°C while stirring until the degree of polymerization of styrene is 10 to 60%. In this prepolymerization step, the rubber-like elastic body is dispersed into particles by stirring.

After completion of the above pre-111i1 polymerization step, suspend polymerization by suspending tribasic calcium phosphate, polyvinyl alcohol, etc. in the aqueous phase as a suspending agent. Usually, polymerization (11 polymerization) is carried out until the degree of polymerization approaches 100%. Note that, if necessary, heating may be continued after this main polymerization step.

Next, the obtained slurry is dehydrated, the beads are separated and dried, and then pelletized by a conventional method to obtain a resin composition. In carrying out one polymerization, additives such as a polymerization initiator and an antioxidant can be used as appropriate, as described above.

The organic peroxides include, for example, 1.1-bis(t-butylperoxy)cyclohexane, l, l-
Peroxyketals such as bis(t-butylperoxy)3.3.5-)limethylcyclohexane, di-t-butylperoxide, 2,5-dimethyl-2,5-di(t
Dialkyl peroxides such as (butylperoxy)hexane, sialperoxides such as benzoyl peroxide and m-toluoyl peroxide, peroxydicarbonates such as dimyristyl peroxydicarbonate, and peroxygens such as t-butylperoxyisopropyl carbonate. Esters.

Examples include hydroperoxides such as cyclohexanone peroxide, ketone peroxides, and p-menthahydroperoxide.

Examples of the molecular weight regulator include α-methylstyrene dimer, n-dodecylmercaptan, tertiary dodecylmercaptan, 1-phenylbutene-2-fluorene, and mercaptans such as dipentene and chloroform;
Examples include terpenes and halogen compounds.

(Resin composition) The styrenic resin composition of the present invention can be obtained as described above, and the styrenic resin composition contains:
A rubbery elastomer is dispersed as particles in a hard phase of styrene polymer.

The styrenic resin composition of the present invention has a rubber particle size of 0.
．． 1 to 1.8 gm, preferably 0.2 to L, Sgm, and the matrix molecules jl, jka,
100,000~300,000. Better is 130,
It is a rubber-modified styrenic resin composition within the range of 000 to 280.000. This composition has excellent gloss and impact resistance, and in particular, the balance thereof is significantly better than that of conventional HIPS (high impact polystyrene).

This rubber particle diameter is 0. If it is less than IILm, the impact resistance of the styrenic resin composition will be insufficient.

On the other hand, when it exceeds 1.81 Lm, the gloss becomes low.

If the matrix molecular weight is less than too or ooo, the impact resistance of the styrenic resin composition will be insufficient, while if it exceeds 300,000, the fluidity during molding will be insufficient.

The definitions and measurement methods of the rubber particle diameter and matrix molecule quality are shown in [Examples] below.

The styrenic resin composition according to the present invention may optionally contain various additives such as known additives, such as stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, and ethylene bisstearate. roamide, organic polysiloxane, mineral oil, etc., and antioxidants such as hindered phenols, hindered bisphenols, hindered trisphenols, and the like.

2.6-di-t-butyl-4-methylphenol, stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, triethylene glycol-bis-3-(3-t-butyl -4-hydroxy-5-
methylphenyl)propionate T, or phosphorus compounds such as tri(2,4-di-t-butylphenyl)7-osphite, 4,4'-butylidene-bis-(
3-Methyl-6-t-butylphenyl-di-tridecyl) phosphite, etc. can be added, and if necessary, stabilizers, dyes, pigments, fillers, lubricants, etc.
A molding agent, a plasticizer, an antistatic agent, etc. can also be added.

Furthermore, the styrenic resin composition of the present invention may optionally contain
Other polymers, such as polyphenylene ether, may also be used.

The styrenic resin composition of the present invention thus obtained has excellent basic properties as a HIPS.

It has excellent gloss and impact resistance, particularly in the balance thereof, and can be suitably used in home appliances, 0A41 devices, various sheet fields, etc.

[Example J Hereinafter, the present invention will be explained in more detail by showing Examples and Comparative Examples, but the present invention is not limited to these Examples.

The composition, physical properties, measurement method, or definition of the polymer is as follows. Further, the symbol SR represents styrene-butadiene, and PS represents polystyrene-based styrenes.

(1) Rubber particle diameter: After staining with osmic acid, a photograph was taken with a transmission electron f-microscope, and the diameter of about 1000 particles was measured at 31:1.

Next, calculate the area average diameter based on the formula below.

This was defined as the rubber particle size.

Area modulus average diameter=Σd+3/Σd, 2 (where di represents the particle size of the i-th particle) (2) Matrix molecule weight (Mw): After dissolving the resin composition in methyl ethyl ketone, the gel component is removed. The solution was centrifuged and the clear liquid containing the matrix components was dried. Thereafter, a 1i% O-2 solution of the matrix component was prepared using tetrahydrofuran as a solvent,
Using a Waters GPC150C, the weighted molecular weight (M w ) was determined in terms of polystyrene.

(3) Styrene content of SB;/rock copolymer: 13c: 50. Measured at IMHz.

(4) Confirmation that there are no random components in the SB block copolymer: After dissolving in chloroform, blowing ozone gas and then reducing with lithium aluminum hydride to decompose the butadiene component, use tetrahydrofuran as a solvent to dissolve the butadiene component. Measurement was performed by GPC, and it was confirmed that styrene chains based on random components were not detected.

(5) Molecule i (Mw) of SB block copolymer: SR block copolymer 0 using tetrahydrofuran as a solvent.
．． A 2% solution was determined in terms of polystyrene using a Waters giGPC.

(8) Molecular weight (Mw) of block PS part: After dissolving in chloroform, ozone gas is blown into it, and then acetic acid/#! ,
After reduction with lead to decompose the butadiene component, it was determined in terms of polystyrene using a Waters GPC using tetrahydrofuran as a solvent.

(7) Izotsu impact f1: Compliant with JIS-7110 (23℃ notched).

(8) Gloss: Compliant with JIS-Z-8741.

(9) Flexural modulus: Compliant with ASTN It 790.

(10) Melt index: Compliant with JSOR1133.

(Example 1) 0.07 parts of n-butyllithium was added to 15 parts of 20% n-hexane solution containing 75 parts of 1,3-butadiene.
The mixture was added as an n-hexane solution and mixed at 80°C for 2 minutes. After all l,3-butadiene lances have been bonded, styrene 25
A modified portion was added and polymerization was further carried out for 2 hours to obtain a block copolymer solution consisting of a 1,3-butadiene polymer block and a styrene polymer block. To the copolymer solution, 1 tsrt-butyl-p-cresol was added as a stabilizer per 9 parts by 100 parts of the copolymer, and the solvent was distilled off under heating to isolate the desired copolymer.

In the obtained SR block co-hair ball coalescence, no random components were detected, the styrene content was 25@% by weight, and the molecular -N was 18
0,000. Block polystyrene molecular spear is 80.0
It was 00.

Method for producing styrenic resin composition (Ib) In a 5-pronged autoclave, the SB obtained in Production Example (Ia) was placed.
800 g of block copolymer, 2,400 g of styrene and 0.
98 g (300 ppm) was charged, and the reaction was carried out at 140°C for 4 hours while stirring at 300 rpm.
The resulting reaction mixture was placed in an autoclave of 3.000
g, 3,000 g of water, tog of polyvinyl alcohol as a suspension stabilizer, 6 g of benzoyl peroxide and 3 g of dicumyl peroxide as fi initiators,
While stirring at 00 rpm, the temperature was raised from 80'O to 140°C at a rate of 30°C/hour, and the reaction was continued for an additional 4 hours to obtain rubber-modified polystyrene beads.

The obtained beads were pelletized by uniaxial extrusion at 220°C, and then molded.

The results are shown in Table 1.

(Examples 2 to 4 and Comparative Examples 1 to 3) In Example 1, except that the rotation speed and the amount of n-dodecyl mercaptan used were changed as shown in Table 1, and the rubber particle diameter and the molecular weight of the matrix were changed. was carried out in the same manner.

The results are shown in Table 1.

(Examples 5 and 6 and Comparative Examples 4 and 5) Examples 5 and 6 were carried out in the same manner as in Example 1, except that the amount of SR block co-hair ball combination used was changed as shown in Table 1.

The results are shown in Table 1.

(Examples 7 to 9 and Comparative Examples 6 to 9) In Example 1, the SB block copolymer compositions were produced according to Production Example (1a) as shown in Table 1, and these were used. Other than that, it was carried out in the same manner.

The results are shown in Table 1.

(Comparative Example 10) When producing an SB block copolymer, in Production Example (la), tetrahydrofuran was used as a randomizing agent, n
- A 10-fold polymer was added to hexane to obtain an SR block copolymer having a random component. The styrene acid content of this product was 1% in the 2 heel portion, and 18 FM% in the block PS portion. The same procedure as in Example 1 was carried out except that this SB block copolymer was used.

The results are shown in Table 1.

(Example 10.11) According to Production Example (la), the SR block copolymer composition was changed as shown in Table 1, and the SB block copolymer content in the resin was 15. It was carried out in the same manner as in Example 1 except that it was made to be.

The results are shown in Table 1.

(Advanced, here is the blank space) [Effects of the invention] According to the present invention, the present invention has excellent gloss and impact resistance, and is particularly excellent in the balance between gloss and resistance [1] compared to conventional high-impact polystyrene. An excellent styrenic resin composition can be provided.

With agent Naoki Fukumura, patent attorney.

"+1', t, tzu

Claims (2)

[Claims] (1) The content of (A) styrenes is 92 to 60% by weight, and (B) the content of styrenes as repeating units is 10 to 50% by weight, and the molecular weight is within the range of 80,000 to 300,000. , obtained by copolymerizing 8 to 40% by weight of a completely block type styrene-butadiene block copolymer in which the weight average molecular weight of the block polystyrene portion is 15,000 to 150,000, and the rubber particle size is 0. ．．
1 to 1.8 μm, and the matrix molecular weight is 100,
000 to 300,000. (2) The styrenic resin composition according to claim 1, wherein the styrene is styrene.