JPH04359955A - Production of nitrile resin composition - Google Patents

Abstract

PURPOSE:To produce, industrially easily and at a low cost, the title compsn. excellent in gas barrier properties without detriment to the mechanical properties characteristic of a conventional nitrile resin compsn. CONSTITUTION:The title compsn. is produced by mixing an emulsion contg. 2-30 pts.wt. high-acrylonitrile (co)polymer obtd. by the emulsion (co)polymn. of 80-100wt.% acrylonitrile with 0-15wt.% at least one monomer selected from 1-6C alkyl acrylates and methacry1ates with an emulsion contg. 70-98 pts.wt. low-acrylonitrile copolymer obtd. by the emulsion copolymn. of 50-80wt.% acrylonitrile with 20-50wt.% at least one monomer selected from 1-6C alkyl acrylates and methacrylates, and coagulating the resulting mixture.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a novel nitrile resin composition having excellent hot melt fluidity and high gas barrier properties.

0002

[Prior Art] Acrylonitrile resin exhibits excellent gas barrier properties based on the intermolecular bonds unique to nitrile groups.
It has excellent chemical resistance to acids, alkalis, and organic solvents, as well as 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 properties and melt moldability of an acrylonitrile resin are contradictory properties, and the higher the content of the acrylonitrile component, the higher the gas barrier properties, but the lower the melt moldability. This is an essential property based on the intermolecular bond specific to the nitrile group, and acrylonitrile resin has two
When the temperature exceeds 00°C, cyclization occurs due to intramolecular condensation, resulting in yellowing and infusibility. For this reason, when the content of the acrylonitrile component exceeds about 85% by weight, melt molding becomes substantially difficult.

JP-A No. 61-69814 discloses that the reason why acrylonitrile-based polymers have low melt moldability is that they have a high molecular weight. (0 or less) Acrylonitrile polymers that can be melt-molded have been proposed. However, in order to melt-mold an acrylonitrile-based polymer having an acrylonitrile component content of about 85% by weight or more, it is necessary to use a high molding temperature, and yellowing and infusibility of the polymer are unavoidable. Further, there are problems in that a reduction in molecular weight more than necessary causes a serious reduction in mechanical properties.

0004

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

[0005]

[Means for Solving the Problems] Therefore, in order to achieve both melt moldability and gas barrier properties, the present inventors developed a low nitrile copolymer with a low content of acrylonitrile component that has excellent melt moldability and excellent gas barrier properties. The present invention was achieved as a result of repeated studies focusing on the use in combination with a high nitrile copolymer having a high content of an acrylonitrile component.

[0006] In order to solve the above object, the present invention has the following configuration. That is, a monomer or monomer consisting of 85 to 100% by weight of acrylonitrile and 0 to 15% by weight of at least one selected from acrylic acid alkyl esters or methacrylic acid alkyl esters having an alkyl group having 1 to 6 carbon atoms. Acrylonitrile polymer or high nitrile copolymer (A) obtained by emulsion polymerization of the mixture 2 to 30
Part by weight, 50-80% by weight of acrylonitrile, and 1 carbon number
A low nitrile copolymer (B )70～
When producing a resin composition consisting of 98 parts by weight, emulsion particles of an acrylonitrile polymer or high nitrile copolymer (A) obtained by emulsion polymerization and emulsion particles of a low nitrile copolymer (B) are combined. The present invention relates to a method for producing a nitrile resin composition, which comprises mixing and then solidifying the composition.

[0007] The constituent elements of the present invention will be explained in detail below. The nitrile resin composition according to the method of the present invention can be molded into films, sheets, containers, etc. by melt molding, and is made from acrylonitrile and an acrylic acid alkyl ester or methacrylic acid alkyl ester having an alkyl group having 1 to 6 carbon atoms. A low nitrile copolymer (B) obtained by emulsion polymerization of a monomer mixture consisting of at least one selected
is a melt moldable resin, and acrylonitrile is 50
~80% by weight, particularly preferably 70~80% by weight from the viewpoint of the balance between melt moldability and gas barrier properties. If it exceeds 80% by weight, melt moldability will deteriorate.

The acrylic acid alkyl ester or methacrylic acid alkyl ester having an alkyl group having 1 to 6 carbon atoms as a copolymerizable component includes methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate,
amyl acrylate, hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate,
Examples include butyl methacrylate, amyl methacrylate, hexyl methacrylate, etc. Among these,
Particularly preferred is methyl acrylate. The amount of at least one type used is preferably 20 to 50% by weight, particularly 20 to 30% by weight. Further, if necessary, less than 5% by weight of other copolymerizable monomers may be used. For example, neutral monomers such as styrene, vinyl acetate, vinyl chloride, vinylidene chloride, vinyl ethyl ether, acidic monomers such as acrylic acid, methacrylic acid, allylsulfonic acid, styrenesulfonic acid, and ammonium of these monomers. salts, alkali metal salts, etc.

Acrylonitrile obtained by emulsion polymerization of a monomer or monomer mixture consisting of acrylonitrile and at least one selected from acrylic acid alkyl esters and methacrylic acid alkyl esters having an alkyl group having 1 to 6 carbon atoms. Polymer or high nitrile copolymer (
A) does not need to be a melt-moldable resin, and preferably has gas barrier properties that are at least twice as high as the low nitrile copolymer (B). Acrylonitrile is 85-100% by weight,
In particular, from the viewpoint of gas barrier properties, 90 to 100% by weight is preferable. The acrylic acid alkyl ester or methacrylic acid alkyl ester having an alkyl group having 1 to 6 carbon atoms as the copolymerization component is preferably the same as the copolymerization component of the low nitrile copolymer (B), and the amount used is at least one type. 0
~15% by weight, especially 0-10% by weight is preferred.

The nitrile resin composition according to the method of the present invention uses a low nitrile copolymer (B) as a matrix resin, in which acrylonitrile polymer or high nitrile copolymer (A) resin is finely dispersed. . Such two-component resins include emulsion particles of acrylonitrile polymer obtained by emulsion polymerization or high nitrile copolymer (
It can be obtained by mixing the emulsion particles of A) and the emulsion particles of the low nitrile copolymer (B), and then coagulating the mixture.

[0011] To give an example of the manufacturing method, first, a two-component emulsion is mixed, and then this mixed emulsion is coagulated, filtered, dried, and melted to obtain pellets. The finer the dispersed particle size, the better the dispersion state of the two components, and the larger the dispersed particle size, the worse the dispersibility, which may cause cracks during molding.
This results in a decrease in mechanical properties. For this reason, the particle size of the emulsion particles of the acrylonitrile polymer or high nitrile copolymer (A) is 0.01 to 0.2 μm, particularly 0.01 to 0.2 μm.
1 μm is preferred. If it is smaller than 0.01 μm, the productivity of the emulsion will be reduced, and if it is larger than 0.2 μm, mechanical properties will be reduced, and if stretched after molding, breakage or whitening will occur. On the other hand, when mixed using pellets, the acrylonitrile polymer or high nitrile copolymer (A) has poor or no melt flowability, making it difficult to mold. Furthermore, in the case of powder blending, the mixing state is macroscopic, and the mechanical properties are significantly deteriorated.

The addition rate of the acrylonitrile polymer or high nitrile copolymer (A) is 2 to 30 parts by weight, especially 5 parts by weight.
~20 parts by weight is preferred. If it is less than 2 parts by weight, the effect on gas barrier properties will be small, and if it is more than 30 parts by weight, the mechanical properties will be significantly reduced.

[0013] 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. Further, the particle size of the emulsion particles can be controlled by emulsifier concentration, monomer concentration, polymerization rate, seed polymerization method, etc.

The composition obtained according to 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 primary molded products such as films, sheets, containers, etc., and can also be heated and subjected to secondary molding such as uniaxial stretching, biaxial stretching, compression molding, vacuum molding, calendar molding, and heat setting. At that time, a known molding machine can be used. Furthermore, depending on the purpose, there is no problem in adding matting agents, colorants, heat stabilizers, ultraviolet absorbers, etc. during the molding process. 2
When stretching in the subsequent molding, the stretching temperature is preferably a temperature at which the acrylonitrile polymer or high nitrile copolymer (A) is easily deformed, and is usually 100 to 150°C, and the melt molding temperature is 1
It can be processed at temperatures lower than 70-220°C.

[0015] The molded article made from the composition of the present invention is
It has excellent gas barrier properties, mechanical properties, and transparency.

[0016]

[Examples] The present invention will be specifically explained below with reference to Examples. In addition, parts and % in the examples represent "parts by weight" and "% by weight" unless otherwise specified.

[0017] Evaluation items and methods in Examples will be described below. <M1> According to ASTM-D1238. <Average particle size> Measured using an image analyzer based on a transmission electron micrograph. <Amount of Oxygen Permeation> A sheet was extruded and further biaxially stretched to obtain a film for measurement. This film was heated at 30℃ and 100℃.
The amount of oxygen permeation was measured under the condition of %RH. <Film physical properties> Strength in the longitudinal and lateral directions of the biaxially stretched film,
Elongation was measured according to ASTM-D638 and expressed as an average value in two directions.

Examples 1 to 5 and Comparative Examples 1 to 31. Production of low nitrile copolymer emulsion (B-1) A mixture consisting of the following components was charged into a stainless steel reactor, and after the inside of the reactor was sufficiently purged with nitrogen, polymerization was carried out at 60° C. for 1 hour with stirring. water
1
47.65 parts acrylonitrile

25.0 parts methyl acrylate

8.33 parts n-dodecyl mercaptan

0.68 parts sodium persulfate

0.07 part ethylenediaminetetraacetic acid-potassium
0.03 parts
Monogen Y-100 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
0.96 parts

Next, a mixture consisting of the following components was continuously added dropwise over a period of 3 hours. water

82.05 parts acrylonitrile

50.0 parts methyl acrylate

16.67 parts n-dodecyl mercaptan

1.36 parts Monogen Y-100

0.36 parts

After completing the dropping, polymerization was further carried out at 60°C for 3 hours, and then unreacted monomers were removed from the emulsion by distillation under reduced pressure to obtain an emulsion (B-1) of the low nitrile copolymer shown in Table 1. Obtained.

2. High nitrile copolymer emulsion (A
-1 to 3) Production A mixture consisting of the following components was charged into a stainless steel reactor, and after the inside of the reactor was sufficiently replaced with nitrogen, the mixture was heated at 60°C with stirring for 1 hour.
Time polymerization was performed. water
4
42.95 parts acrylonitrile

90.0 parts Methyl acrylate

10.0 parts Sodium persulfate

0.07 parts Ethylenediaminetetraacetic acid-potassium 0.1
Part 2 Monogen Y-100
2.4
7th part

Thereafter, unreacted monomers were removed from the emulsion by vacuum distillation to obtain a high nitrile copolymer emulsion (A-1) shown in Table 1. Similarly, using 100 parts of the monomer mixture, polymerization was carried out for 3 hours with the composition shown in Table 1,
High nitrile copolymer emulsions (A-2-3) were obtained.

[0023]

[Table 1]

Low nitrile copolymer emulsion (B-1
) and high nitrile copolymer emulsions (A-1 to A-3) were mixed in various compositions shown in Table 2 to obtain nitrile resin compositions. The results are shown in Table 2.

[0025]

[Table 2]

It can be seen that the composition produced by the method of the present invention has excellent gas barrier properties, moldability, and transparency, and also has good film strength and elongation.

Examples 6 to 10 and Comparative Examples 4 to 63. Production of low nitrile copolymer emulsion (B-2) A mixture consisting of the following components was charged into a stainless steel reactor, and after the inside of the reactor was sufficiently purged with nitrogen, polymerization was carried out at 60° C. for 1 hour with stirring. water
1
47.65 parts acrylonitrile

23.33 parts methyl acrylate

10.0 parts n-dodecyl mercaptan
0
．． 68 parts Sodium persulfate

0.07 part ethylenediaminetetraacetic acid-potassium
0.03 parts
Monogen Y-100
0.96 parts

0
[028] Next, a mixture consisting of the following components was continuously added dropwise over a period of 3 hours. water

82.05 parts acrylonitrile

46.67 parts methyl acrylate

20.0 parts n-dodecyl mercaptan

1.67 parts Monogen Y-100

0.54 parts

After completing the dropping, polymerization was further carried out at 60°C for 3 hours, and then unreacted monomers were removed from the emulsion by distillation under reduced pressure to obtain an emulsion (B-2) of the low nitrile copolymer shown in Table 2. Obtained.

4. High nitrile copolymer emulsion (A
-4) Production A mixture consisting of the following components was charged into a stainless steel reactor, and the inside of the reactor was sufficiently purged with nitrogen.
Time polymerization was performed. water
1
47.65 parts acrylonitrile

30.0 parts methyl acrylate

3.33 parts sodium persulfate

0.07 parts Ethylenediaminetetraacetic acid-potassium 0.0
Part 3 Monogen Y-100
0.6
4th part

[0031] Next, a mixture consisting of the following components was mixed with 3
It was dripped continuously over time. water

82.05 parts acrylonitrile

60.0 parts Methyl acrylate

6.67 parts Monogen Y-100

0.36 parts

After finishing the dropping, 6
Polymerization was further carried out at 0° C. for 3 hours, and then unreacted monomers were removed from the emulsion by distillation under reduced pressure to obtain a high nitrile copolymer emulsion (A-4) shown in Table 2.

[0033]

[Table 3]

Low nitrile copolymer emulsion (B-2
) and high nitrile copolymer emulsion (A-1, 4) were mixed in various compositions shown in Table 2 to obtain nitrile resin compositions. The results are shown in Table 4.

[0035]

[Table 4]

It can be seen that the composition prepared by the method of the present invention has excellent gas barrier properties, moldability, and transparency, and is also good in terms of film strength and elongation.

[0037]

Effects of the Invention The method for producing a nitrile resin composition of the present invention maintains the mechanical properties of ordinary nitrile resin compositions and produces nitrile resin compositions with excellent gas barrier properties using ordinary manufacturing equipment. It can be manufactured industrially easily and inexpensively under certain conditions.

Claims (2)

[Claims] Claim 1: Acrylonitrile 85-100% by weight
and 0 to 15% by weight of at least one selected from acrylic acid alkyl esters and methacrylic acid alkyl esters having an alkyl group having 1 to 6 carbon atoms. 2 to 30 parts by weight of acrylonitrile polymer or high nitrile copolymer (A), 50 to 80% by weight of acrylonitrile, and 1 to 1 carbon atoms
A low nitrile copolymer (B) obtained by emulsion polymerization of a monomer mixture consisting of 20 to 50% by weight of at least one selected from acrylic acid alkyl esters and methacrylic acid alkyl esters having 6 alkyl groups. 70-9
When producing a resin composition consisting of 8 parts by weight, emulsion particles of an acrylonitrile polymer or high nitrile copolymer (A) obtained by emulsion polymerization and emulsion particles of a low nitrile copolymer (B) are combined. A method for producing a nitrile resin composition, which comprises mixing and then solidifying the composition. Claim 2: The particle size of the emulsion particles of the acrylonitrile polymer or high nitrile copolymer (A) is 0.01.
The manufacturing method according to claim 1, wherein the thickness is 0.2 μm.