JPH05148402A - Nitrile resin composition and its production - Google Patents

Abstract

PURPOSE:To obtain a nitrile resin composition which has good melt flowability and high gas barrier property, composed of an acrylonitrole copolymer of the core-shell type prepared by multi-stage polymerization process and a specified graft copolymer. CONSTITUTION:(A) An acrylonitrile core-shell type copolymer prepared by 2 or more, multi-stage polymerization of 60 to 85wt.% of acrylonitrile and 15 to 40wt.% of a 1 to 6C alkyl (meth)acrylate where the core layer polymer (A2) is formed by polymerization at a 85 to 100wt.% concentration of acrylonitrile, then at 60 to 85wt.% in the presence of (A2) to form the shell layer polymer (A1) so that (A1) content is kept at 2 to 40wt.% is combined with (B) a graft copolymer which is prepared by emulsion polymerization of the monomer mixture same as (A) in the presence of a synthetic rubber containing more than 50wt.% of 1,3-conjugated diene whereby the subject nitrile resin composition containing more than 5wt.% of (A) is obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a nitrile resin composition and a method for producing the same. More specifically, the present invention relates to a novel nitrile resin composition having excellent hot melt fluidity and high gas barrier properties, and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Acrylonitrile resins show excellent gas barrier properties based on the intermolecular bond peculiar to nitrile groups,
It has excellent chemical resistance to acids, alkalis, organic solvents, and mechanical properties such as flexural modulus, strength, and creep resistance, and is widely used as a well-balanced resin as a material for films, sheets, and containers. .. However, the gas barrier property and the melt moldability of the acrylonitrile resin are contradictory properties. As the content of the acrylonitrile component increases, the gas barrier property increases, but the melt moldability decreases. This is an essential property based on the intermolecular bond peculiar to the nitrile group, and the acrylonitrile resin undergoes cyclization due to intramolecular condensation at a temperature exceeding 200 ° C., causing yellowing and infusibility. Therefore, when the content of the acrylonitrile component is about 85% or more, the melt molding becomes substantially difficult.

In Japanese Patent Application Laid-Open No. 61-69814, it is recognized that acrylonitrile-based polymers have low melt moldability due to their high molecular weight, and the molecular weight is reduced (reduced viscosity 1. (0 or less) Acrylonitrile polymers capable of melt molding have been proposed. However, in order to melt-mold an acrylonitrile-based polymer having an acrylonitrile component content of about 85% or more, it is necessary to raise the molding temperature to high temperature, and yellowing and infusibilization of the polymer cannot be avoided. Further, there is a problem that an excessive decrease in molecular weight causes a significant decrease in mechanical properties.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel nitrile resin composition having excellent hot melt fluidity and high gas barrier property, and a method for producing the same.

[0005]

Therefore, the inventors of the present invention, in order to achieve both melt moldability and gas barrier property, have a low nitrile content graft copolymer excellent in melt moldability and having a low content of acrylonitrile component. The present invention has been achieved as a result of repeated studies focusing on the combined use with a high nitrile copolymer having a high content of an acrylonitrile component having excellent gas barrier properties. The present invention has the following configurations in order to solve the above object.

That is, the present invention relates to acrylonitrile 60-8.
Obtained by emulsion polymerization of a monomer mixture consisting of 5% by weight and at least 15 to 40% by weight of at least one alkyl acrylate or methacrylic acid alkyl ester having an alkyl group having 1 to 6 carbon atoms. Acrylonitrile 6 in the presence of acrylonitrile copolymer (A) and a synthetic rubber containing 50% by weight or more of 1,3 conjugated diene
0 to 85% by weight and at least one kind selected from alkyl acrylate or methacrylic acid alkyl ester having an alkyl group having 1 to 6 carbon atoms 15 to 40% by weight
In a resin composition comprising a graft copolymer (B) obtained by emulsion polymerization of a monomer mixture consisting of a), the acrylonitrile copolymer (A) is at least 5% by weight.
And the acrylonitrile copolymer (A) is obtained by multi-stage polymerization of at least two or more steps. First, (a-1) 85 acrylonitrile in the monomer mixture is added.
Core layer polymer (A-1) composed of an acrylonitrile polymer or a high nitrile copolymer polymerized at 100 to 100% by weight
And (a-2) a shell layer polymer (A- comprising a low nitrile copolymer obtained by polymerizing 60 to 85% by weight of acrylonitrile in the monomer mixture in the presence of the core layer polymer. 2) polymerized, wherein the core layer polymer (A-1) in the acrylonitrile copolymer (A) accounts for 2 to 40% by weight with respect to (A). Is.

The method of the present invention comprises acrylonitrile 60-8.
Obtained by emulsion polymerization of a monomer mixture consisting of 5% by weight and at least 15 to 40% by weight of at least one alkyl acrylate or methacrylic acid alkyl ester having an alkyl group having 1 to 6 carbon atoms. In the presence of 1 to 20 parts by weight of acrylonitrile copolymer (A) and 1 to 20 parts by weight of a synthetic rubber containing 50% by weight or more of 1,3 conjugated diene, 60 to 85% by weight of acrylonitrile and an alkyl group having 1 to 6 carbon atoms are added. At least one selected from alkyl acrylates or methacrylic acid alkyl esters
When a resin composition comprising a graft copolymer (B) obtained by emulsion polymerization of 80 to 99 parts by weight of a monomer mixture consisting of 5 to 40% by weight is used, the acrylonitrile copolymer is used in the resin composition. Polymer (A) is at least 5% by weight, and acrylonitrile copolymer (A) is obtained by multistage polymerization of at least two stages. First, (a-1) acrylonitrile in the monomer mixture 85
Core layer polymer (A-1) composed of an acrylonitrile polymer or a high nitrile copolymer polymerized at 100 to 100% by weight
And (a-2) a shell layer polymer (A- comprising a low nitrile copolymer obtained by polymerizing 60 to 85% by weight of acrylonitrile in the monomer mixture in the presence of the core layer polymer. 2) is polymerized, and the core layer polymer (A-1) is added to 2 to 40
A method for producing a nitrile-based resin composition, which comprises mixing the acrylonitrile copolymer (A) and the graft copolymer (B) contained in a weight percentage.

The constituent features of the present invention will be described in detail below.
It The nitrile resin composition according to the present invention is obtained by melt molding.
Can be formed into films, sheets, containers, etc.
Acrylonitri in the presence of synthetic rubber containing role diene
Acrylic acid having an alkyl group having 1 to 6 carbon atoms
From alkyl ester or methacrylic acid alkyl ester
Emulsify a monomer mixture consisting of at least one selected
The graft copolymer (B) obtained by polymerization is melt-moldable
The synthetic rubber used in the present invention is
Monomers with conjugated dienes, eg 1,3-butadien
Homopolymers of benzene, isoprene, chloroprene and the like
And at least one of these dienes and others
Monomers such as acrylonitrile, methacrylonitrile
, Styrene, methyl acrylate, methyl methacrylate
It may be a copolymer with the above. Preferably, a conjugated diene-based single
The monomer is 1,3-butadiene, and as a comonomer
Is acrylonitrile. Synthetic rubber is a conjugated diene-based unit
Those containing 50% by weight or more of the monomer are preferable. Graph
The content of synthetic rubber when emulsion-polymerizing the copolymer is 1 to
20 parts by weight, but preferably 2 to 15 parts by weight
It In addition, acrylonite copolymerizes in the presence of synthetic rubber.
50% to 80% by weight, especially melt moldability and gas barrier
From the viewpoint of balance of properties, 70 to 80% by weight is preferable. 80 layers
If it exceeds the amount%, the melt moldability is deteriorated.

Examples of the alkyl acrylate or alkyl methacrylate having an alkyl group having 1 to 6 carbon atoms as a copolymerization component include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, Examples thereof include hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, and hexyl methacrylate. Of these, methyl acrylate is particularly preferable. The amount used is preferably 20 to 50% by weight, and more preferably 20 to 30% by weight. If necessary, other copolymerizable monomer may be used in an amount of less than 5% by weight. For example,
Styrene, vinyl acetate, vinyl chloride, vinylidene chloride,
Neutral monomer such as vinyl ethyl ether, acrylic acid,
Methacrylic acid, allylsulfonic acid, styrenesulfonic acid and other acidic monomers and ammonium salts of these monomers,
Examples thereof include alkali metal salts.

Acrylonitrile obtained by emulsion-polymerizing a monomer or a mixture of monomers consisting of acrylonitrile and at least one selected from alkyl acrylate or methacrylic acid alkyl ester having an alkyl group having 1 to 6 carbon atoms. The copolymer (A) is a melt-moldable resin, and preferably has a gas barrier property higher than that of the graft copolymer (B). The acrylonitrile copolymer (A) is produced from at least two-stage polymerized core-shell type particles. The core-shell type particles have good adhesion between the core layer and the shell layer, are less likely to cause problems during molding such as whitening and peeling during stretch molding, and are also excellent in dispersibility of the high nitrile copolymer after melt molding.

The core layer polymer (A-1) is composed of an acrylonitrile polymer obtained by polymerizing acrylonitrile in an amount of 85 to 100% by weight or a high nitrile copolymer, and does not need to be a melt-moldable resin. 90 from sex
-100% by weight is preferred. If it is less than 85% by weight, the gas barrier property is low. As the acrylic acid alkyl ester or methacrylic acid alkyl ester having an alkyl group having 1 to 6 carbon atoms, the copolymerization component is preferably the same as the copolymerization component of the graft copolymer (B), and the amount used is at least one. 0-15% by weight, especially 0-10% by weight
Is preferred.

The shell layer polymer (A-2) is a melt-moldable resin composed of a low nitrile copolymer. The acrylonitrile to be copolymerized is 60 to 85% by weight, particularly 70 to 80% by weight.
Weight percent is preferred. If it exceeds 80% by weight, the melt moldability deteriorates. The core layer polymer (A-1) in the acrylonitrile copolymer (A) is 2 to 40% by weight, and particularly 5 to 2%.
0% by weight is preferred. If it is less than 2% by weight, the gas barrier property is low, and if it is more than 40% by weight, the melt moldability becomes poor.

As a particularly preferred acrylonitrile copolymer (A), a core layer polymer (A-1) made of an acrylonitrile polymer or a high nitrile copolymer and a shell layer polymer (A made of a low nitrile copolymer ( A-2) has an intermediate layer, which is obtained by polymerizing 60 to 85% by weight of acrylonitrile in the monomer mixture, and the acrylonitrile component is contained in the low nitrile copolymer. It should be larger than the polymer. The core-shell type multilayer particle having the intermediate layer is excellent in adhesiveness between the core layer and the shell layer, and in the case of a gradient type intermediate layer having a composition gradient such that the closer the intermediate layer is to the core layer, the closer to the composition of the core layer. Is even better.

The nitrile resin composition of the present invention comprises a graft copolymer (B) and a shell layer polymer (A-2) consisting of a low nitrile copolymer as a matrix resin, in which an acrylonitrile polymer or a high polymer is used. The resin of the core layer polymer (A-1) made of a nitrile copolymer is finely dispersed.
Such a two-component resin is prepared by mixing the core-shell type emulsion particles of the acrylonitrile copolymer (A) obtained by emulsion polymerization with the emulsion particles of the graft copolymer (B) and then solidifying the mixture. can get. As an example of the production method, first, a two-component emulsion is mixed, and then the mixed emulsion is coagulated, filtered, dried and melted to obtain pellets. In addition, mixing with pellets and blending with powder can be performed.
The content of the acrylonitrile copolymer (A) is at least 5% by weight, particularly preferably 10% by weight or more, and when it is less than 5% by weight, the effect on the gas barrier property is small.

Emulsion particles of each polymer can be produced by emulsion polymerization. As the emulsifier, known anionic emulsifiers, cationic emulsifiers, and nonionic emulsifiers can be appropriately selected and used. The particle size of the emulsion particles can be controlled by the emulsifier concentration, the monomer concentration, the polymerization rate, the seed polymerization method and the like.

The composition obtained by the present invention can be easily molded by known molding methods such as extrusion molding, injection molding, blow molding, and inflation molding. For example, it can be processed into a primary molded product such as a film, a sheet, a container and the like, and further subjected to secondary molding such as uniaxial stretching, biaxial stretching, compression molding, vacuum molding, calendering and heat setting.
At that time, a known molding machine can be used. In addition, depending on the purpose, a matting agent, a coloring agent, a heat resistance stabilizer, an ultraviolet absorber, etc. may be added during the molding process. Two
When stretching in the subsequent molding, the stretching temperature is preferably a temperature at which the acrylonitrile polymer or the high nitrile copolymer (A) is easily deformed, usually 100 to 150 ° C, and the melt molding temperature 1
It can be processed at a temperature lower than 70 to 220 ° C. The molded product molded from the composition of the present invention has excellent gas barrier properties, mechanical properties and transparency.

[0017]

EXAMPLES The present invention will be specifically described below with reference to examples. In addition, the part and% in an Example represent a "weight part" and "weight%" unless there is particular notice. The evaluation items and methods in the examples will be described below. <MI> According to ASTM-D1238. <Oxygen Transmission Amount> A sheet was extruded and biaxially stretched to obtain a film for measurement. This film is 30 ℃, 65%
The oxygen permeation amount was measured under the condition of RH. <Physical properties of film> Strength of the biaxially stretched film in the longitudinal and transverse directions,
Elongation is measured according to ASTM-D638 and expressed as an average value in two directions.

Examples 1-5 and Comparative Examples 1-3 1. Production of Graft Copolymer Emulsion (B-1 to 2) A mixture of the following components was charged into a stainless reactor, the inside of the reactor was sufficiently replaced with nitrogen, and then polymerization was carried out at 60 ° C. for 1 hour with stirring. Water 147.01 parts Acrylonitrile 25.0 parts Methyl acrylate 8.33 parts Sodium persulfate 0.04 parts n-Dodecyl mercaptan 1.1 parts Ethylenediaminetetraacetic acid-potassium 0.04 parts * 1 Monogen Y-100 1.28 Part * 2 NIPOL-1551 21.47 parts (* 1 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) (* 2 Acrylonitrile-butadiene rubber latex solid content 51% manufactured by Zeon Corporation)

A mixture consisting of the following components was continuously added dropwise thereto over 3 hours. Water 80.59 parts Acrylonitrile 50.0 parts Methyl acrylate 16.67 parts Sodium persulfate 0.02 parts n-Dodecyl mercaptan 2.2 parts Monogen Y-100 0.72 parts After the dropping is completed, further at 60 ° C. Polymerize for 4 hours,
Then, the unreacted monomers were removed from the emulsion by distillation under reduced pressure, and the graft copolymer emulsion (B
-1) was obtained. Similarly, 100 parts of the monomer mixture was polymerized with the composition shown in Table 1 to obtain a graft copolymer emulsion (B-2). The results are shown in Table 1.

2. Production of core-shell type acrylonitrile copolymer emulsion (A-1 to 2) A mixture of the following components was charged into a stainless reactor, the inside of the reactor was sufficiently replaced with nitrogen, and then polymerization was carried out at 60 ° C. for 2 hours with stirring. It was Water 147.1 parts Acrylonitrile 30.0 parts Methyl acrylate 3.3 parts Sodium persulfate 0.04 parts Ethylenediaminetetraacetic acid-potassium 0.04 parts Monogen Y-100 1.2 parts

A mixture consisting of the following components was continuously added dropwise thereto for 3 hours. Water 81.65 parts Acrylonitrile 50.0 parts Methyl acrylate 16.67 parts n-Dodecyl mercaptan 2.5 parts Sodium persulfate 0.03 parts Monogen Y-100 0.8 parts After completion of dropping, further at 60 ° C. Polymerize for 3 hours,
Then, unreacted monomers were removed from the emulsion by distillation under reduced pressure to obtain a high nitrile copolymer emulsion (A-1) shown in Table 1. Similarly, 100 parts of the monomer mixture was polymerized with the composition shown in Table 1 to obtain a high nitrile copolymer emulsion (A-2). The results are shown in Table 1.

[0022]

[Table 1]

Graft copolymer emulsion (B-1 to
2) and an acrylonitrile copolymer emulsion (A-1
To 2) were mixed in various compositions shown in Table 2 to obtain a nitrile resin composition. The results are shown in Table 2. The nitrile resin composition of the present invention is excellent in gas barrier properties and moldability, is also excellent in transparency, and is also good in film strength and elongation.

[0024]

[Table 2]

[0025]

The nitrile resin composition and the method for producing the same according to the present invention are a nitrile resin composition having excellent gas barrier properties while maintaining the mechanical properties of ordinary nitrile resin compositions as they are, and a method for producing the same. It can be easily manufactured industrially and at low cost using ordinary manufacturing equipment and manufacturing conditions.

Claims (5)

[Claims] 1. A monomer mixture comprising 60 to 85% by weight of acrylonitrile and at least 15 to 40% by weight of at least one selected from alkyl acrylate or methacrylic acid alkyl ester having an alkyl group having 1 to 6 carbon atoms. Acrylonitrile copolymer (A) obtained by emulsion polymerization of acrylonitrile, and 60 to 85% by weight of acrylonitrile and 1 to 6 carbon atoms in the presence of a synthetic rubber containing 50% by weight or more of 1,3 conjugated diene. A resin comprising a graft copolymer (B) obtained by emulsion polymerization of a monomer mixture containing 15 to 40% by weight of at least one selected from alkyl acrylates or methacrylic acid alkyl esters having an alkyl group. In the composition, the acrylonitrile copolymer (A) is at least 5% by weight, and the acrylonitrile copolymer (A) is The polymer (A) is obtained by at least two-stage multi-stage polymerization, and first, (a-1) 85 acrylonitrile in the monomer mixture is added.
Core layer polymer (A-1) composed of an acrylonitrile polymer or a high nitrile copolymer polymerized at 100 to 100% by weight
And (a-2) a shell layer polymer (A- comprising a low nitrile copolymer obtained by polymerizing 60 to 85% by weight of acrylonitrile in the monomer mixture in the presence of the core layer polymer. 2) polymerized, wherein the core layer polymer (A-1) in the acrylonitrile copolymer (A) accounts for 2 to 40% by weight with respect to (A). .. 2. The nitrile resin composition according to claim 1, wherein a core layer polymer (A-1) made of an acrylonitrile polymer or a high nitrile copolymer and a shell layer weight made of a low nitrile copolymer. There is an intermediate layer between the compound (A-2) and the intermediate layer, which is obtained by polymerizing 60 to 85% by weight of acrylonitrile in the monomer mixture, and the proportion of the acrylonitrile component is low. A nitrile resin composition, which is larger than a nitrile copolymer. 3. The method according to claim 1, wherein the graft copolymer is obtained by emulsion polymerization of 80 to 99 parts by weight of a monomer mixture in the presence of 1 to 20 parts by weight of synthetic rubber. 4. A monomer mixture comprising 60 to 85% by weight of acrylonitrile and at least 15 to 40% by weight of at least one selected from alkyl acrylate or alkyl methacrylate having an alkyl group having 1 to 6 carbon atoms. Acrylonitrile copolymer (A) obtained by emulsion polymerization of acrylonitrile, and 60 to 85% by weight of acrylonitrile and 1 to 6 carbon atoms in the presence of a synthetic rubber containing 50% by weight or more of 1,3 conjugated diene. A resin comprising a graft copolymer (B) obtained by emulsion polymerization of a monomer mixture containing 15 to 40% by weight of at least one selected from alkyl acrylates or methacrylic acid alkyl esters having an alkyl group. In producing the composition, the resin composition contains at least 5% by weight of acrylonitrile copolymer (A). And the acrylonitrile copolymer (A) is obtained by multistage polymerization of at least two or more stages. First, (a-1) 85 acrylonitrile in the monomer mixture is added.
Core layer polymer (A-1) composed of an acrylonitrile polymer or a high nitrile copolymer polymerized at 100 to 100% by weight
And (a-2) a shell layer polymer (A- comprising a low nitrile copolymer obtained by polymerizing 60 to 85% by weight of acrylonitrile in the monomer mixture in the presence of the core layer polymer. 2) is polymerized, and the core layer polymer (A-1) is added to 2 to 40
A method for producing a nitrile-based resin composition, which comprises mixing the acrylonitrile copolymer (A) and the graft copolymer (B) contained in a weight percentage. 5. The production method according to claim 3, wherein the polymerization step (a-1) for obtaining the (a′-1) core layer polymer.
Is completed, the monomer mixture in the polymerization step (a-2) is added continuously or in divided portions so that the proportion of acrylonitrile in the monomer mixture accounts for 60 to 85% by weight, and A core layer polymer having an intermediate layer having a larger proportion of acrylonitrile component than the shell layer polymer described below is obtained, and (a'-2) acrylonitrile in a monomer mixture in the presence of the core layer polymer having the intermediate layer. Is obtained by polymerizing a shell layer polymer (A-2) made of a low nitrile copolymer obtained by polymerizing 60 to 85% by weight of nitrile resin composition.