JPS63304011A - Production of thermoplastic resin - Google Patents

Abstract

PURPOSE:To obtain the titled resin outstanding in impact and heat distortion resistances, etc., by incorporating, in the presence of a rubbery polymer, a mixture comprising acrylonitrile and styrene, alpha-methylstyrene mixture and acrylonitrile mixture in the reaction system in this order while carrying out polymerization. CONSTITUTION:First, 2-40pts.wt. of a monomer mixture of acrylonitrile and styrene in the weight ratio of the former to the latter of 10-40/90-60 is polymerized, using as the emulsifying agent a compound of formula (R is 10-24C alkyl or alkylene; M is Na or K), in the presence of 5-30pts.wt. of a rubbery polymer. Thence, 50-90pts.wt. of alpha-methylstyrene or a second monomer mixture containing >=80wt.% of alpha-methylstyrene is added to the system followed by gradually adding a third monomer mixture containing >=70wt.% of acrylonitrile so that, in combination with the second monomer mixture, the weight ratio: alpha-methylstyrene/acrylonitrile is 95-65/5-35, while carrying out polymerization, thus obtaining the objective thermoplastic resin.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention is directed to the production of a-methylstyrene in the presence of a rubbery polymer.
It relates to a method of polymerizing acrylonitrile, styrene, and vinyl monomers copolymerizable with these, and is an industrial method for producing resins with excellent impact resistance, heat deformation resistance, and little discoloration due to heating during or after hot molding. It relates to manufacturing advantageously.

(Prior Art and Problems) Conventionally, a method has been proposed in which monomers containing α-methylstyrene, acrylonitrile, and styrene as main components are polymerized in the presence of a diene rubber. However, copolymers obtained by these conventional methods do not have sufficient impact resistance when the content of α-methylstyrene is high.
Furthermore, in that case, there was a drawback that the polymerization conversion rate was low. Moreover, when the content of α-methylstyrene is small, there is a drawback that sufficient heat deformation resistance cannot be obtained.

A method has been proposed in which an α-alkyl-substituted aromatic vinyl monomer and a vinyl cyanide monomer are blended with a rubber-modified graft copolymer when produced by an emulsion polymerization method. However, it was difficult to sufficiently improve both impact resistance and thermal deformation resistance.

R-OROOM CI) 0 H200M (In the formula, 几 represents C1o~024 alkyl group or alkylene group, M represents sodium or kawaram) (Means and effects for solving the problem) The present inventors In order to overcome these drawbacks, we conducted extensive studies and found that first, a monomer mixture containing acrylonitrile and styrene as main components was polymerized in the presence of a rubbery polymer, and then a-
A method was adopted in which a monomer mixture containing methylstyrene as the main component was added into the system, and then a monomer mixture containing acrylonitrile as the main component was added little by little to polymerize. 6) as the general formula [I
By using the compound shown in ], a thermoplastic resin with excellent impact resistance, heat deformation resistance, and little discoloration due to heat can be obtained. Furthermore, the polymerization conversion rate is high, there are few aggregates during polymerization, and the latex is stable. Find out that this is true.

The present invention provides a monomer mixture consisting of 95 to 70 parts of acrylonitrile, styrene, α-methylstyrene, and other monomers in the presence of 5 to 30 parts (by weight, the same applies hereinafter) of a rubbery polymer. When polymerizing the emulsifier (B), a compound represented by the general formula CI) is used as an emulsifier.
A monomer mixture (A) in which 2 to 5 parts are used and the weight ratio of acrylonitrile/styrene is 10 to 40/90 to 60.
After polymerizing 2 to 40 parts, 50 to 90 parts of monomer mixture 03) containing α-methylstyrene monomer or a-methylstyrene at 80% (wt%, the same shall apply hereinafter) or more is added. , and then combined with α-methylstyrene monomer or a monomer mixture CB) with other monomers so that the weight ratio is α-
Methylstyrene/acrylonitrile = 95~6515~
Acrylonitrile monomer or acrylonitrile monomer to make it 35! By adding and polymerizing a mixture of I1 bodies (0) little by little, a thermoplastic resin with excellent impact resistance, heat deformation resistance, and little thermal discoloration can be obtained, and the polymerization conversion rate is high and there are few aggregates during polymerization. , the gist of this paper is a method for producing thermoplastic resins whose latex is stable.

That is, in the method of the present invention, rubbery polymers 5 to
95 to 70 parts of α-methylstyrene in the presence of 30 parts;
When acrylonitrile, styrene, and monomers copolymerizable with these are polymerized, the compound represented by the general formula (I) is used as the emulsifier (6), and the monomer mixture is
monomer mixture CB), monomer mixture (0 (A), CB
), (0). At this time, the timing and cooling method of adding the emulsifier (2) are not particularly limited, and the addition of the monomer mixture (a), a3), and (C) together with the addition of the emulsifier It may be added continuously (or may be added in parts), but it is preferable to add most of it after adding the monomer mixture (A).

Monomer mixture (A), (B), (0 is (A), CB),
C), but the method of addition is not particularly limited. For example, after most of the monomer mixture (A) has been polymerized, the monomer mixture Q3) is added, and then the monomer mixture Q3) is added. The polymer mixture (C') is added little by little. Monomer mixture (0
The addition method may be continuous or divided, but the weight ratio of α-methylstyrene and acrylonitrile monomer present in the system is 40% of the polymerization conversion rate.
Until 90/10. It is preferable to add so that the ratio is desirably 9515 or higher.

Here, the number of rubbery polymer parts, monomer mixture (A), CB)
(The number of parts of 0 and the composition have an optimum point depending on the desired physical properties of the resin, but the number of parts of the rubbery polymer is 5 to 30.
% is preferable, and other than that is not preferable because of deterioration of impact resistance, heat deformation resistance, moldability, etc. The rubbery polymers used include diene rubbers such as polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene, acrylic rubbers such as polybutyl acrylate,
Polyolefin rubber such as ethylene-propylene-nonconjugated diene rubber is used.

The monomer mixture (A) is 2 to 40 parts, preferably 2 to 20 parts.
The weight ratio of acrylonitrile/styrene is 10 to 40/90 to 60, and up to 30% of acrylonitrile and styrene may be replaced by other vinyl spinning wheels.

Examples of vinyl monomers include α-methylstyrene, chlorostyrene, methyl methacrylate, methacrylnitrile, and phenylmaleimide. If the number of parts of the monomer mixture (3) is too large, heat deformation resistance will decrease, and if it is too small, impact resistance will decrease, which is not preferable.

The monomer mixture (B) is 50 to 90 parts, and desirably contains 80% or more of α-methylstyrene, and 20% or less of other materials based on the monomer mixture CB) i o o%. A vinyl monomer may also be included.

Examples of other vinyl monomers include styrene, acrylonitrile, methacrylnitrile, methyl methacrylate, and phenylmaleimide. When the number of parts of the single substance mixture CB) is less than 50 parts, the heat deformation resistance decreases, and 9
If it exceeds 0 parts, it is unfavorable from the viewpoint of polymerization conversion rate and impact resistance. Further, if the amount of other vinyl monomers contained in the monomer mixture (B) exceeds 20%, it is not preferable from the viewpoint of heat deformation resistance and moldability.

Monomer mixture (0 contains 70% or more acrylonitrile,
And the weight ratio of α-methylstyrene/acrylonitrile contained in the monomer mixture (B) and the monomer mixture (6) is 95-6575-35.

If this weight ratio is higher than this range, the polymerization conversion rate and impact resistance will decrease, and if it is lower than this range, heat discoloration will become significant and heat deformation resistance will decrease, which is not preferable. Examples of other vinyl monomers that may be included in the monomer mixture (0) include α-methylstyrene, styrene, chlorostyrene, methyl methacrylate, methacrylnitrile, and phenylmaleimide.

The emulsifier (6) used in the present invention has the general formula [
I]. In the general formula [I], R is an alkyl group or alkylene group having 10 to 24 carbon atoms, preferably 12 to 18 carbon atoms, and M is sodium or potassium. In the present invention, by using the compound represented by the general formula [I] as an emulsifier (B), the polymerization conversion rate,
In particular, the polymerization conversion rate of α-methylstyrene was significantly improved.
The content of α-methylstyrene in the resin component increases,
Moreover, the amount of α-methylstyrene monomer remaining in the resin is reduced, and heat deformation resistance can be improved.

Furthermore, the generation of aggregates during polymerization is reduced, and the stability of the latex and bath is improved. The number of parts of emulsifier (2) used is 0.2 to 5.
part, more preferably 0.5 to 3 parts.

If it is less than 0.2 parts, the polymerization conversion rate and stability of the latex will decrease, and if it exceeds 5 parts, the physical properties of the resulting resin will deteriorate, which is not preferable. If necessary, a dispersant (6) such as a sodium salt of a β-naphthalenesulfonic acid formalin condensate or a polycarboxylic acid type polymeric surfactant is added in an amount of 1 to 50% based on the emulsifier (2). It is also possible to do so.

Polymerization can be carried out by conventional emulsion polymerization methods. For example, the monomer may be polymerized with a polymerization initiator in the presence of a rubbery polymer. Examples of the polymerization initiator include peroxides such as potassium persulfate, ammonium persulfate, and cumene hydroperoxide. The polymerization accelerator, degree of polymerization regulator, etc. can also be selected and used as appropriate. The polymerization temperature is preferably 30 to 80°C.

A known method may be used to obtain the resin from the obtained latex. For example, it may be salted out with a salt such as calcium chloride, magnesium chloride, or aluminum sulfate, or it may be coagulated with an acid such as sulfuric acid or hydrochloric acid. Further, if necessary, conventional stabilizers, plasticizers, lubricants, pigments, fillers, antistatic agents, etc. may be added.

(Examples) The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples.

Examples 1-6, Comparative Examples 1-3 Water 200
Part sodium formaldehyde sulfoxylate 0.4
〃Ethylenediaminetetraacetic acid disodium 0.01
tt ferrous sulfate 0.0
025//Pour these substances into a reactor with a stirrer,
After deoxidizing and heating and stirring at 60°C in a nitrogen stream, the rubbery polymer latex and the monomer mixture (A) shown in Table 1 were prepared.
, Q3) and (0) were charged sequentially. Monomer mixture (A)
(B) was fed continuously at a rate of 10 parts/hour, (B) was fed all at once, and at the beginning, eggs were fed continuously at a rate of 3 parts/hour. After the completion of the preparation, stirring was continued at 60° C. for 1 hour to complete the polymerization. Emulsifier (6) was added in an amount of 10% of the amount used together with monomer mixture (A), and the remaining 90% was added together with monomer mixture 03).

A phenolic antioxidant is added to the obtained latex of each polymer, coagulated in a calcium chloride water bath, washed with water, filtered, dried, pelletized using a vented extruder, and physically A measurement of properties is provided.

From the results in Table 1, it can be seen that the thermoplastic resins of the present invention represented by Examples have excellent impact resistance, heat deformation resistance, and low O1 thermal coloring properties.

(Effect of the invention) In the method of polymerizing a monomer mixture in the presence of a rubbery polymer according to the present invention, the composition of the monomers is limited, and the monomer mixture (5), 03), (0) is By adding 100% and using a specific emulsifier, it can be produced with a high polymerization conversion rate and less aggregates, and has excellent impact resistance and heat deformation resistance.
Thermoplastic resins with little thermal coloring can be industrially advantageously produced.

Margin Table-1 Table-1 (continued) PBd: Polybutadiene rubber (latex-like) with an average particle size of 2,600 mm PBA: Polybutyl acrylate rubber (latex-like) with an average particle size of 3,000 mm EPDM: Average particle size of 3,600 mm Ethylene-propylene non-conjugated diene rubber (latex form) AN: Acrylic nitrile, St: Styrene, MMA: Methyl methacrylate, αMSt: α-methylstyrene, tDM: Tertiary dodecyl mercaptan, OHP: Cumene hydroperoxide, D- In the compound represented by the general formula [I] above, R is an alkyl group having 16 to 18 carbon atoms, and M is potassium D-2: In the compound represented by the general formula [I] above, R is an alkyl group having 12 to 14 carbon atoms. Group, M is potassium D-3 Sodium dilaurate E-1: Sodium salt of β-naphthalenesulfonic acid formalin condensate Polymerization conversion rate Conversion rate at the end of polymerization (relative to charged monomer) remaining/2M5t amount Polymerization Unreacted a in the latex at the end
Amount of MSt (relative to monomer charged) Amount of aggregates After polymerization, the latex is filtered through a 100-mesh sieve, and the remaining solid content after drying is the weight% of the total amount of monomer charged and rubber-like polymer. Deformation resistance temperature: ASTM D-648, 18, 6#/-
One load (''C) Izot impact value: ASTM D-256, notched, 23°CCkQ-CM/CM) Tensile crab ASTM D-636, 23°CkQ/d)
Fluidity: Koka type B method flow, 260°C 1 load 100k
g/d (xlOcc/5ea) Thermal colorability: A flat plate of 150111X 100mflX an was made by injection molding, and it was observed with the naked eye that it was ○...
*: Almost no coloring, Δ: Slightly colored, X: Colored.

Claims (1)

[Claims] (1) In the presence of 5 to 30 parts by weight of a rubbery polymer
When polymerizing 0 parts by weight of the monomer, a compound represented by the following general formula [I] is used as the emulsifier (D), and the weight ratio is acrylonitrile/styrene = 10 to 40/90 to
After polymerizing 2 to 40 parts by weight of a monomer mixture (A) of acrylonitrile and styrene 60, a monomer mixture containing 80% by weight or more of α-methylstyrene monomer or α-methylstyrene (B ) 50 to 90 parts by weight are added, and then combined with the monomer mixture (B) so that the weight ratio is α-methylstyrene/acrylonitrile = 95 to 65/5 to 3.
5. A method for producing a thermoplastic resin, which comprises adding a monomer mixture (C) containing 70% by weight or more of acrylonitrile little by little and polymerizing. General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [ I ] (In the formula, R represents an alkyl group or alkylene group of C_1_0_ to_2_4, and M represents sodium or potassium.)