JPS588716A - Production of transparent thermoplastic resin - Google Patents

Abstract

PURPOSE:To obtain a resin excellent in transparency, toughness, heat distortion resistance and gas barrier property and useful as a material for packaging, containers, etc. by copolymerizing acrylonitrile with an aromatic vinyl compound in the presence of a specified rubber-graft polymer latex. CONSTITUTION:A rubber-graft polymer latex is obtained by continuously adding 60-30pts.wt. monomer mixture consisting of 30-75wt% acrylonitrile, 20-45wt% aromatic vinyl and 5-25wt% (meth)acrylate ester 40-70pts.wt. (solid content) rubbery polymer latex, average particle diameter 0.05-0.20mu, consisting of 60- 100wt% 1,3-conjugated diene monomer (e.g., butadiene) and 40-0wt% other ethylenically unsaturated monomers under a condition of emulsion polymerization. A monomer mixture containing 65-80wt% acrylonitrile and 35-20wt% aromatic vinyl is polymerized in the presence of the rubber-graft polymer latex to obtain a resin containing 7-25wt% rubbery polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides industrial thermoplastic resins containing aromatic olefins containing a high proportion of acrylonitrile and having excellent transparency, toughness, high heat distortion temperature, and high gas barrier properties. The present invention relates to a method of manufacturing the invention which is particularly advantageous.

Copolymers of acrylonitrile and aromatic olefins and rubber reinforced compositions of copolymers are well known. However, since acrylonitrile and aromatic olefins have significantly different radical reactivity, in a normal polymerization method, the composition ratio of the polymer produced differs between the initial stage and the latter stage of the polymerization, resulting in a non-uniform polymer. Therefore, it is difficult to obtain a transparent copolymer containing a high proportion of acrylonitrile at one time.
A method of polymerizing acrylonitrile and styrene or α-methylstyrene by adding them to an aqueous medium while keeping the reflux temperature constant, as described in No. 3.268, and Japanese Patent Specification No. 235, No. It is known that transparent copolymers can be obtained by measuring the heat of polymerization using a calorimeter and adding monomers according to the amount of heat generated.

In order to improve the impact resistance of an acrylonitrile-styrene copolymer containing a high proportion of acrylonitrile, as described in Japanese Patent Publication No. 5,594/1980, acrylonitrile-styrene copolymer in the presence of a diene rubber latex is used.
A method of copolymerizing styrene, and a method of blending a kraft copolymer obtained by graft copolymerizing acrylonitrile and styrene onto diene rubber, as described in Japanese Patent Publication No. 1983-33,574, are known. However, all of these methods use gas chromatography or calorimeters to monitor the progress of polymerization and supply monomer accordingly, which makes it difficult to use polymerization equipment. Not only is the operation complicated, but the amount of grafting cannot be controlled to enhance the reinforcing effect.
There have been problems in industrially producing resins that have sufficient impact resistance and transparency.

As a result of intensive research to improve this point, the present inventors have made a ring polymer of a 1,3-conjugated diene polymer or a copolymer of a monoolefin monomer and a 1,3-conjugated diene, A monomer mixture consisting of acrylonitrile-aromatic vinyl-methacrylic acid ester or acrylic acid ester is continuously added to the mixture and graft copolymerized to obtain a rubber-graft copolymer (first polymer). By copolymerizing acrylonitrile and aromatic vinyl in the presence of a first polymer, the above problems have been improved, and rubber-reinforced acrylonitrile has excellent transparency, impact resistance, and thermoformability. We have discovered that aromatic vinyl copolymer resins (hereinafter abbreviated as nitrile resins) can be obtained extremely easily.

The rubber-graft copolymer described in this specification is a polymer obtained by polymerizing monomers in the coexistence of the rubber-like polymer shown below, and is useful for the purpose of the present invention. It is not an essential requirement for the present invention that all the polymer present be grafted onto the rubbery polymer.

Next, to explain the present invention in detail, at least one
, a rubbery polymer consisting of 60 to 100% by weight of a 3-conjugated diene monomer and 40 to 0% by weight of at least one other ethylene type lower saturated monomer capable of radical copolymerization (
Hereinafter, this will be referred to as a rubbery polymer. ) out of latex,
40 to 70 parts by weight (as solid content) of a rubbery polymer having an average particle diameter of 0.05 to 0.20 μ, 30 to 75 weight % of acrylonitrile, and at least one aromatic vinyl 2
graft polymerization by continuously adding 60 to 30 parts by weight of a monomer mixture consisting of 0 to 45% by weight and 5 to 25% by weight of at least one methacrylic ester to acrylic ester under emulsion polymerization conditions; A graft copolymer is obtained. Next, in the presence of this first polymer, a monomer mixture consisting of 65 to 80% by weight of acrylonitrile and 20 to 35% by weight of at least one aromatic vinyl is added to is 7-25 weight 5
- By copolymerizing using a known method so that the L1 of the present invention has good transparency, a high heat distortion temperature, and excellent toughness and gas barrier properties, -1,1 thread resin can be produced very easily.

In the present invention, a rubber-like polymer is used as a ring polymer, and a graft copolymer (first Polymers) are essential for imparting toughness and transparency to the final resin.

The rubbery polymer contains at least one 1,3-conjugated diene 6
0 to 100 parts by weight and at least one other ethylene-type subsaturated monomer capable of radical copolymerization therewith. Suitable dienes include, for example, butadiene, imprene, 2,3-dimethylbutadiene, piperylene and chloroprene. Ethylene-type New Year's monocapsules include styrene and aral 6-ken, methyl, ethyl, ■-butyl and 2-ethylhexyl acrylate such as styrene and α-methylstyrene, and n-butyl and 2-ethylhexyl methacrylate. Although monomers such as acrylic and methacrylic esters, esters of fumaric acid, and unsaturated nitriles such as acrylonitrile and methacrylonitrile can be used, a particularly preferred monomer is acrylonitrile. In this rubbery polymer, 1
, 3-conjugated diene is less than 60%, sufficient toughness cannot be imparted to the nitrile resin.

The latex of the rubbery polymer must have an average particle size within the range of 0.05 to 0.20 μ, and 0.0
If it is less than 5μ, toughness cannot be imparted to the resin, and
If it is 62μ or more, the resin becomes cloudy and its transparency decreases.

Acrylonitrile 30% to the above rubbery polymer latex
~75% by weight, aromatic mlIl vinyl 20-4% by weight and methacrylic acid ester or acrylic acid ester 5
Rubber-like polymer 4
By continuously adding 60 to 30 parts by weight to 0 to 70 parts by weight, graft copolymerization is carried out to obtain a graft copolymer. The composition of the monomer mixture during this graft polymerization closely influences the properties of the final nitrile resin and is extremely important.

In general, acrylonitrile-aromatic olefin copolymers tend to have a fairly wide compositional distribution due to their low copolymerization reactivity as mentioned above, and this can be reinforced with grafted rubber particles. However, it is thought that it is difficult to provide sufficient transparency and toughness because the compatibility between the rubber particles and the copolymer decreases, and the difference in refractive index between them is large. It has been found that these problems can be solved at once by combining a three-component monomer mixture in a limited proportion according to the method of the invention with the surface phase of the rubbery polymer particles.

Describing in detail the effect of each component in the above monomer mixture, acrylonitrile is used in a proportion of 30 to 75% by weight. Acrylonitrile content is 35% by weight
In the following cases, the graft copolymer and acrylonitrile-
Since the compatibility with the aromatic olefin copolymer decreases, the nitrile resin becomes opaque and its toughness decreases. Further, if the content is more than 70% by weight, the molding processability of the final resin will be lowered, and it will be more likely to be colored and deteriorated by heat, which is not preferable.

The aromatic vinyl compound is used in a proportion of 20 to 45% by weight. If it is less than 20% by weight or more than 45% by weight, the refractive index of the polymer is significantly different from that of the acrylonitrile-aromatic olefin copolymer, which impairs the transparency of the final composition, which is not preferable. Suitable examples of the aromatic vinyl include styrene, α-alkylstyrene, α-methylstyrene, and their alkyl-substituted derivatives such as vinyltoluene and improbenyltoluene, and these may be used alone or in a mixture of two or more. Ru.

The methacrylic ester or acrylic ester is used in an amount of 5 to 25% by weight. The reason for using these monomers as essential components of the graft polymer is that the acrylonitrile-aromatic olefin copolymer acrylonitrile-lyl J1'! It provides good compatibility even with a fairly wide compositional distribution of -position and aromatic vinyl units,
This is because it has the effect of improving the toughness and transparency of the final composition. However, if the amount used is less than 5%, the effect will be poor, and if it is more than 25%, the heat strain temperature of the molded product will be lowered, which is not preferable. As the acrylic ester, methyl and ethyl esters are particularly preferred, and as the methacrylic ester, methyl, ethyl, propyl and butyl esters are particularly preferred, and these can be used alone or in a mixture of two or more.

Graft copolymerization is carried out by emulsion polymerization of the above three monomer mixtures in the presence of a rubbery polymer latex. The continuous addition of the monomer mixture in the polymerization with is extremely important to make the final resin transparent. That is, when the monomer mixture is added all at once at the initial stage of polymerization, the transparency of the resulting lO-- graft polymer decreases. Through this polymerization, a part of the copolymer chain consisting of three types of monomer units is chemically bonded to the rubber-like polymer molecules, resulting in a rubber-graft with favorable properties different from that of a simple polymer mixture. A copolymer is formed.

In the graft emulsification 11, conventional emulsion polymerization techniques are used, and initiators, emulsifiers, chain transfer agents and other substances can be added as appropriate before or during polymerization. The ratio of the three-component copolymer to the rubbery polymer is determined by polymerizing the monomer mixture at a ratio of 60 to 30 parts by weight to 40 to 70 parts by weight of the rubbery polymer. It is necessary to form the three-component copolymer in a ratio of 150 to 40 parts, preferably 100 to 50 parts, per 100 parts of the polymer.

The acrylonitrile-aromatic olefin copolymerization in the presence of the above-mentioned rubber-graft copolymer can be carried out by the well-known emulsion polymerization method and then by known salting-out treatment or other polymer recovery methods. A nitrile resin is obtained.

In the resin production method of the present invention, the ratio of the three-component polymer component consisting of acrylonitrile, aromatic vinyl, and methacrylic acid ester or acrylic acid ester to the rubbery polymer component is set to 7 to 7. It is preferable to be able to grasp 25 double fingers. The content of this rubbery polymer component is calculated using the following formula.

Content (%) - ([Parts by weight of solid content of the rubbery polymer charged] / [(Parts by weight of the solid content of the rubbery polymer charged)" -
(Parts by weight of the charged monomer) x (polymerization rate)) X (polymerization fraction of the rubber-graft copolymer in the final resin)

M of rubber-graft copolymer in the final resin (unit fraction = [
Parts by weight of solids of the rubber-graft copolymer charged]/[
(Rubber-graft copolymer solid content in parts by weight)
- (Parts by weight of monomer charged x polymerization rate)] As the relative proportion of the rubbery polymer increases, the toughness of the resin composition increases, but the gas barrier properties tend to decrease. is observed, and the heat strain temperature also decreases. Therefore, it is desirable that the proportion of the rubbery polymer is 25% by weight or less.

The acrylonitrile-aromatic vinyl copolymerization in the presence of the rubber-graft polymer described above can be carried out by emulsion polymerization. In order to obtain a polymer that is transparent and has excellent molding fluidity, it is necessary to devise a method for preparing monomers so as to produce a polymer with as uniform a composition as possible. A method such as charging the monomer composition is preferred. The proportion of acrylonitrile units in the copolymer is required to be 60% by weight or more in order to have sufficient gas barrier properties, but as the acrylonitrile component increases, the molding fluidity of the resin decreases. , its upper limit should be suppressed to 80% by weight. In addition, the degree of polymerization of the copolymer is expressed as a reduced viscosity value of 0.5 to 2.0 (
Copolymer 0.5 in dimethylformamide iooml
A solution of 2 at 25° C.) is preferred. Suitable aromatic vinyls to be copolymerized with acrylonitrile include styrene, α-alkylstyrenes, α-methylstyrenes, and their alkyl-substituted derivatives such as vinyltoluene, impropenyl), luene, etc. It can be used alone or as a mixture of two or more.

The resin obtained by the method of the present invention is thermoplastic and can be made into a wide variety of molded articles by various methods known for molding thermoplastic polymers, such as extrusion, blowing, and calendering. Heat stabilizers, colorants, light stabilizers, processing aids, and the like can be added to this resin as appropriate.

The resin obtained by the method of the present invention has excellent transparency,
Due to its toughness and high heat distortion temperature, as well as excellent solvent resistance and gas barrier properties, it is very useful as a packaging material, and is used as a material for manufacturing packaging containers such as films and bottles for liquids and solids. Particularly useful.

Next, examples of the present invention will be shown. All parts used in the examples are parts by weight unless otherwise indicated.

14- Example 1 (1) Production of rubbery polymer 1. 3-Butadiene 70 parts Acrylonitrile 30 Semi-hardened beef tallow soda soap 1.41 Sodium condensed naphthalene sulfonate 0.11 Ammonium persulfate 0.
311-Dodecylmercaptan 0.6N Distilled water 100N or more of the raw materials were charged into a pressure-tight sealed polymerization vessel equipped with a stirrer, and polymerization was carried out at 52°C for 13 hours under a nitrogen atmosphere.

As a result, the monomer conversion rate was 96%. The average particle diameter of latex was measured using an electron microscope and was found to be 0.
．． It was 07μ.

(2) Preparation of graft copolymer Distilled water containing 30 parts of rubbery polymer latex (solid content) and 2 parts of sodium diargylsulfosuccinate is added to bring the total amount of the aqueous dispersion to 207 parts. This was placed in a reaction vessel equipped with a stirring device, and stirred under a nitrogen stream for 5 minutes.
Add the following mixture at 2°C.

Ammonium persulfate 0.3 parts Distilled water
30゛Continuously add the following ingredients kept at 52°C over a period of 1 hour. Thereafter, the mixture was stirred at 52° C. for 1.5 hours to obtain a graft copolymer.

Acrylonitrile 10 parts styrene
13〃Methyl methacrylate
7〃Turn Yard Denrumel Power Ptano
The conversion rate of 0.5 monomer was 82.

(3) Production of nitrile resin In the presence of the graft copolymer latex described above, acrylonitrile and styrene were copolymerized with the composition shown below.

Graft copolymer (as solid content) 30 parts acrylonitrile 67I styrene
33'pentaerythritol tetra(
3-1,8 parts mercapto) Globionate Ammonium persulfate 0.151 Sodium metabisulfite 0.15/1 Sodium dioctyl sulfosuccinate 2 Distilled water
2001 Polymerization was carried out at 52° C. according to the method described in British Patent Specification No. 663,268. The polymerization yield was 86 inches, and the content of rubbery polymer in the resin was 14 inches. After adding an emulsion of 2,6-di-t-butyl-p-cresol and dilaurylthiodipropionate as a heat stabilizer to this latex, it was salted out, solidified, washed with water, and dried to form a white powder. An IJ-based copolymer resin was obtained.

This resin powder was molded using a compression molding machine at 190℃ and 150Kf/
Compression molding was performed under CD conditions to obtain a molded product for physical property testing.

The melt index value of the polymer is 2.1 (5
4/lo min), light transmittance 81.2, heat distortion temperature 83
．． 7℃, Izotsu impact strength? , 8 Kp-cm/
cm, oxygen gas 17- permeation rate 30 ec-mR-/m' + 241T+"
ajm was shown. On the other hand, the oxygen gas permeation rate of vinylideno chloride film, which is known as a commercially available film with excellent gas barrier properties, is 48 Ce mit/7n"2
411'r-abn.

The test methods and units for the above physical properties are as follows.

Melt Inodex: A8TM Test Method D-1238
-62T, using the melt index value, 190
℃, the amount extruded under a load of 12.5 kg, g-710
It is indicated by m1n.

Light transmittance: ASTM test method 1)-174(i-6
Measured on a 1 m thick sheet using 2T and displayed.

Izot impact strength: ASTM test method 1)-256-
Measured at 20°C using a notched test piece according to
It is expressed as 2.tyn/an.

Heat distortion temperature: ASTM test l! 7:I) -548-
56 and expressed in °C.

Oxygen permeation rate: 0 according to ASTM test method D~1-34
, CC-m i /-/m
"・24Hr・-18--・atm 25°C.

Comparative Example 1 Using the rubbery polymer shown in Example 1, acrylonitrile and styrene were copolymerized with the composition shown below.

Diene rubber (as solid content) 12 parts Acrylonitrile 67 Styrene
33N Benotaerythritol Tetra (
3-1,8 #Mercapto) Globionate Azobisisobutyronitrile 0.31 Dioctylsulfosuccinate 2
Distilled water 2001 Polymerization was carried out at 60"C according to the method described in Japanese Patent Publication No. 5,594/1984, and treated in the same manner as in Example 1 to obtain a white powdery nitrile copolymer resin. I got it.

The polymerization yield was 82%, and the content of rubbery polymer in the resin was 1%.
It was 2.7chi. The physical properties of this resin are melt index 0.8, light transmittance 40.3%, and heat distortion temperature 8.
4.1°C, Izot impact strength Examples 2 to 4. Comparative example 2~
4 Using the same rubbery polymer latex as in Example 1, a nitrile copolymer resin (also The physical properties of the resin were as shown in Table 2.

Table 1 below. (By performing acrylonitrile-styrene copolymerization in the presence of a rubber-graft copolymer made by graft copolymerizing an acrylic acid ester, excellent transparency and toughness that could not be easily achieved with conventional technology can be achieved.) It has now become possible to easily produce a thermoplastic copolymer resin of a high proportion of acrylonitrile and aromatic vinyl that has both high heat distortion temperature and gas barrier properties.

Patent applicant: Asahi Kasei Industries, Ltd. 23- -127~

Claims (1)

[Claims] At least one 1,3-conjugated diene monomer 60-10
0% by weight and at least 1% by weight that can be radically copolymerized therewith.
30 to 75% of acrylonitrile is added to a rubbery polymer latex with an average particle diameter of 0.05 to 0.20μ obtained by polymerizing 40 to 0% by weight of other ethylenically unsaturated monomers.
Weight: at least one aromatic vinyl 20-45 weight i
% and at least one methacrylic ester or acrylic ester at a ratio of 60 to 30 parts by weight based on 40 to 70 parts by weight of the diene copolymer. 65-80% by weight of acrylonitrile and 35-20% by weight of at least one aromatic vinyl compound in the presence of a rubber-graft polymer latex polymerized by continuous addition under polymerization conditions. A method for producing a transparent thermoplastic resin, which comprises copolymerizing the rubber-like polymer so that the content of the rubbery polymer in the resin is 7 to 25% by weight.