JPH0665438A - Polyolefinic resin composition - Google Patents

Abstract

PURPOSE:To obtain a polyolefine resin composition, comprising a polyolefinic resin and a specific copolymer in a specified proportion, excellent in permanent antistatic properties and moldability and useful as packaging materials, etc. CONSTITUTION:The objective composition is obtained by including (B) 1-50 pts.wt. copolymer, having 5000-500000 weight-average molecular weight and prepared by copolymerizing a monomer mixture composed of (i) 1-50wt.% monomer such as 2-sulfoethyl methacrylate having sulfonate group with (ii) 1-50wt.% (meth)acrylate monomer having a polyoxyalkylene chain, (iii) 20-98wt.% (meth) acrylate monomer having a 12-22C alkyl group and (iv) 0-70wt.% other copolymerizable monomers in (A) 100 pts.wt. polyolefinic resin such as PE.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin resin composition having antistatic properties, and more particularly to a polyolefin resin composition having permanent antistatic properties.

[0002]

2. Description of the Related Art Polyolefin resins are relatively inexpensive and have excellent mechanical properties, heat resistance, transparency, electrical insulation properties, etc., so that food, clothing, home appliances, furniture,
It is used in a very large amount as a packaging material for toys, miscellaneous goods, or as an agricultural film.

However, the polyolefin resin is liable to be charged with static electricity, and is obtained during the production of films, sheets, fibers, and other molded products, or during the post-processing or post-treatment of these molded products. When using the product, it is easy for problems due to static electricity such as dust absorption and sparks to occur.

To overcome this drawback, various methods have been proposed in the past. The method of applying an antistatic agent (Japanese Examined Patent Publication No. 50-28101) requires a step of applying an antistatic agent in addition to the molding step, which causes a problem of reduced productivity, and it may be deteriorated with time or washed. There is also a problem that the antistatic effect decreases.

The method of kneading an antistatic agent into a resin (Japanese Patent Publication No. 64-2137) does not require a coating step,
The problem of reduced productivity is solved, but the surface of the molded product is stained by the bleed-out of the kneaded antistatic agent, the appearance is deteriorated, and the antistatic effect is deteriorated due to the aging of the kneaded antistatic agent. There's a problem.

The method of kneading polyoxyalkylene glycol (JP-A-51-143049) has a problem that the permanent antistatic property is poor. The method of modifying a polyolefin resin with carbobetaine as a chemical modification method (Japanese Patent Publication No. 63-60041) has a problem of deteriorating the original physical properties of the polyolefin resin.

[0007]

As described above, in the case where the conventionally known antistatic treatment is applied, there is a problem that the antistatic performance, particularly the permanent antistatic performance is inferior or the physical properties inherent to the polyolefin resin are deteriorated. Yes, and the solution was desired.

In view of the above circumstances, the present invention provides a polyolefin resin composition having excellent antistatic properties, particularly permanent antistatic properties, and excellent moldability without deteriorating the original physical properties of the polyolefin resin. The purpose is to do.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to achieve the above-mentioned object, and as a result, have found that a sulfonic acid group, a polyoxyalkylene chain and a long-chain alkyl group as a side chain are added to a polyolefin resin. A compound containing a specific amount of a group-containing specific copolymer has excellent antistatic performance, especially permanent antistatic performance, and does not deteriorate the physical properties of the polyolefin resin. It has been found that the resin composition has excellent moldability and completed the present invention.

That is, the present invention comprises: (a) 100 parts by weight of a polyolefin resin, (b) 1 to 50% by weight of a monomer having a sulfonic acid group, and a (meth) acrylate monomer having a polyoxyalkylene chain. 1 to 50% by weight, carbon number 1
Obtained by copolymerizing a monomer mixture consisting of 20 to 98% by weight of a (meth) acrylate monomer having 2 to 22 alkyl groups and 0 to 70% by weight of another copolymerizable monomer. The present invention relates to a polyolefin resin composition comprising 1 to 50 parts by weight of a copolymer having a weight average molecular weight of 5,000 to 500,000.

[0011]

In the present invention, examples of the polyolefin resin as the component a include high-density polyethylene, low-density polyethylene, linear-low-density polyethylene, polypropylene, ethylene-propylene copolymer, and the like. To be used alone or in admixture of two or more.

In the present invention, the copolymer as the component b is a monomer having a sulfonic acid group, a (meth) acrylate monomer having a polyoxyalkylene chain, and a carbon number of 12
A copolymer of a (meth) acrylate monomer having an alkyl group of about 22 to 22 and optionally another copolymerizable monomer, which has a molecular structure of It may be random, block or graft.

The above copolymerization can be carried out by utilizing a bulk polymerization method, a solution polymerization method or the like. Further, for the purpose of homogenizing the copolymer, the whole amount or a part of the monomer, the polymerization initiator and the chain transfer agent may be dropped and polymerized. Further, for the purpose of synthesizing a block copolymer or a graft copolymer, a polymerization initiator having a plurality of peroxide groups in the molecule may be used.

Examples of the monomer having a sulfonic acid group include 2-sulfoethyl (meth) acrylate and 2-sulfoethyl (meth) acrylate.
Examples thereof include sulfopropyl (meth) acrylate, methallyl sulfonic acid and styrene sulfonic acid. The sulfonic acid group contained in this monomer can be converted to a copolymer and then converted to an alkali metal salt if necessary.

The sulfonic acid group-containing monomer is contained in the monomer mixture in an amount of 1 to 50% by weight, preferably 5 to 30% by weight.
Used. If it is less than 1% by weight, the antistatic effect is small,
When it exceeds 50% by weight, the compatibility with the polyolefin resin is deteriorated and the original physical properties of the polyolefin resin are deteriorated.

Having a polyoxyalkylene chain (meth)
The acrylate monomer is an ester of (meth) acrylic acid with a compound having a polyether moiety obtained by polymerizing oxyalkylene having 2 to 4 carbon atoms. Specifically, polyoxyethylene mono (meth) acrylate, polyoxypropylene mono (meth) acrylate, polyoxybutylene mono (meth) acrylate, polyoxyethylene polyoxypropylene mono (meth) acrylate , Methoxypolyoxyethylene mono (meth) acrylate, butoxypolyoxyethylene mono (meth) acrylate, phenoxypolyoxypropylene mono (meth) acrylate
And the like. The degree of polymerization of the oxyalkylene group of the polyoxyalkylene chain is not particularly limited, but it is usually preferably in the range of 2 to 90.

The (meth) acrylate monomer having a polyoxyalkylene chain is used in the monomer mixture in an amount of 1 to 50% by weight, preferably 5 to 30% by weight. 1% by weight
When it is less than 50% by weight, the antistatic effect is small, and when it exceeds 50% by weight, the compatibility with the polyolefin resin is deteriorated and the original physical properties of the polyolefin resin are deteriorated.

The (meth) acrylate monomer having an alkyl group having 12 to 22 carbon atoms includes dodecane (meth) acrylate, tridecane (meth) acrylate, tetradecane (meth) acrylate and pentadecane ( (Meta) acrylate, hexadecane (meta) acrylate, heptadecane (meta) acrylate, octadecane (meta) acrylate, nonadecane (meta) acrylate, eicosane (meta) acrylate, uneicosan (meta) Examples include acrylate and Doeicosan (meta) acrylate. When a (meth) acrylate monomer having an alkyl group having less than 12 carbon atoms or more than 22 carbon atoms is used, the compatibility with the polyolefin resin is deteriorated, and the physical properties inherent to the polyolefin resin are deteriorated.

The (meth) acrylate monomer having an alkyl group having 12 to 22 carbon atoms is 20 in the monomer mixture.
~ 98 wt%, preferably 30-70 wt% is used. If it is less than 20% by weight, the compatibility with the polyolefin resin will be poor, and if it exceeds 98% by weight, the antistatic effect will be deteriorated.

Other copolymerizable monomers are not particularly limited, but include, for example, acrylonitrile, methyl (meth) acrylate, ethyl (meth) acrylate.
And propyl (meth) acrylate, butyl (meth) acrylate, maleic anhydride, phenylmaleimide and the like.

The amount of the copolymerizable monomer used is 0 to 70% by weight, preferably 0 to 50% by weight in the monomer mixture.
Is. If it exceeds 70% by weight, the antistatic effect decreases,
Further, the compatibility with the polyolefin resin is deteriorated and the physical properties are deteriorated.

The weight average molecular weight of the copolymer composed of such a monomer mixture is 5,000 to 500,000, preferably 20,000 to 200,000. 5,0
When it is less than 00, the original physical properties of the polyolefin resin are deteriorated, and when it exceeds 500,000, the compatibility with the polyolefin resin is deteriorated and the physical properties are deteriorated.

In the present invention, the mixing ratio of the component a polyolefin resin and the component b copolymer is 1 to 50 parts by weight of the component b copolymer with respect to 100 parts by weight of the component a polyolefin resin. Weight part, preferably 5 to 30 parts by weight. If it is less than 1 part by weight, the antistatic effect is small,
If it exceeds 50 parts by weight, the original physical properties of the polyolefin resin will deteriorate.

As the method of mixing the polyolefin resin of the component a and the copolymer of the component b, the two may be mixed by using a melt mixer such as a Banbury mixer, a single screw extruder or a twin screw extruder. Alternatively, they may be blended during injection molding or extrusion molding and mixed by utilizing the kneading effect of these molding machines.

The polyolefin resin composition of the present invention comprises
In addition to containing the above a and b components as essential components, if necessary, a heat deterioration inhibitor, an ultraviolet absorber, an anti-blocking agent, a lubricant, a nucleating agent, a pigment, a polymer alloy compatibilizer, General-purpose resins, other resins such as engineering plastics, fibers such as glass fibers, carbon fibers, polyamide fibers, silica, aluminum, calcium carbonate,
An inorganic filler such as talc, mica, titanium oxide, carbon black or potassium titanate may be included.

[0026]

INDUSTRIAL APPLICABILITY As described above, the polyolefin composition of the present invention contains the polyolefin resin as the component a and the resin b.
By blending a specific amount of a specific copolymer as a component, it becomes excellent in antistatic property, particularly permanent antistatic property, without impairing the original physical properties of the polyolefin resin.

[0027]

EXAMPLES Next, the present invention will be specifically described with reference to Examples. The parts in the following production examples and examples are based on weight. The weight average molecular weight of the copolymer is a value determined by gel permeation chromatography.

Production Example 1 A glass 4-necked flask equipped with a 2-liter stirrer was equipped with a reflux condenser, a thermometer, a dropping funnel, and a nitrogen gas blowing tube, and 100 parts of methyl isobutyl ketone was used as a solvent.
90 parts of heptadecane methacrylate was added, the reaction system was filled with a nitrogen gas atmosphere, and the temperature was raised to 50 ° C.

Next, 5 parts of 2-sulfoethyl methacrylate, 5 parts of polyoxyethylene (10 mol) monomethacrylate, and 1.0 part of diisopropyl peroxydicarbonate as a polymerization initiator were dissolved. The mixed solution
After being uniformly added dropwise at 50 ° C. over 6 hours, the temperature was maintained for 1 hour.

The copolymer solution thus obtained was mixed with 14
The solvent was distilled off under reduced pressure at 0 ° C. for 2 hours, the mixture was cooled and then pulverized to obtain a copolymer A. This copolymer A was a white powder and had a weight average molecular weight of 50,000.

Production Example 2 Four kinds of copolymers B to B were produced in the same manner as in Production Example 1 except that the monomer composition, solvent and polymerization initiator were changed as shown in Table 1.
I got E. The properties of the copolymers B to E (appearance and weight average molecular weight) are as shown in Table 1.

Production Example 3 Four kinds of copolymers F to F were prepared in the same manner as in Production Example 1, except that the monomer composition, solvent and polymerization initiator were changed as shown in Table 2.
Got I. Properties of the copolymers F to I (appearance and weight average molecular weight) are as shown in Table 2. The copolymers F to I are outside the scope of the present invention.

[0033]

[Table 1]

[0034]

[Table 2]

Example 1 As a polyolefin resin, low-density polyethylene [Sumikasen F210-6 manufactured by Sumitomo Chemical Co., Ltd.] or polypropylene [Chitsuso Polypro K7 manufactured by Chitso Co., Ltd.]
014] was added to the copolymers A to E in the proportions shown in Table 3 and premixed with a tumbler for 20 minutes, and then Laboplast Mill MOD manufactured by Toyo Seiki Seisakusho Co., Ltd.
Using an EL-30C15 single-screw two-stage dullage type extruder, melt kneading at a kneading temperature shown in the same table to form a pellet,
Seven types of resin compositions were obtained.

Next, this resin composition was dried at 85 ° C. for 5 hours and then molded using an IS-25EP injection molding machine manufactured by Toshiba Machine Co., Ltd. at the cylinder temperature shown in the same table to obtain the physical properties. Sample No. for measurement Test pieces 1 to 7 were produced.

Comparative Example 1 As the polyolefin resin, the same low-density polyethylene or polypropylene as in Example 1 was used, and the copolymers D to I and polyoxyethylene (10 mol) glyco- were used.
In the following Example 1,
In the same manner as above, melt kneading was carried out at a kneading temperature shown in the same table to form a pellet, thereby obtaining 9 kinds of resin compositions. This resin composition was molded by the same method as in Example 1 at the cylinder temperature shown in the same table, and sample No. 8-16
The test piece of was produced.

[0038]

[Table 3]

[0039]

[Table 4]

[0040]

[Table 5]

The sample No. prepared in Example 1 and Comparative Example 1 described above. The surface specific resistance, Bicatus softening point, flexural modulus, tensile strength, and Izod impact strength of the test pieces 1 to 16 were examined in the following manner. The results are shown in Tables 6 and 7 below.

<Surface specific resistance> Using a surface specific resistance measuring device [Hirest-Tester manufactured by Mitsubishi Petrochemical Co., Ltd.], the surface after 1 minute under the conditions of 20 ° C., humidity of 50% and applied voltage of 500 volts. The specific resistance (Ω) was measured. "Untreated" in the table means that a test piece of 10 cm x 10 cm x 2 mm is 20
It is a value measured after conditioning for 1 day at 50 ° C and 50% humidity, and "washing treatment" means that the test piece is 1 ° C at 20 ° C.
It is a value measured by adjusting the condition after ultrasonic cleaning for a period of time.

<Vicat Softening Point> ASTM D1525
Therefore, the measurement was performed.

<Flexural Modulus> A for low density polyethylene
Measurements were made according to ASTM D747 and ASTM D790 for polypropylene.

<Tensile Strength> AS for low density polyethylene
Measurements were made according to TM D6760 and for polypropylene according to ASTM D638.

<Izod impact strength> ASTM D25
According to 6, the measurement was performed.

[0047]

[Table 6]

[0048]

[Table 7]

As is apparent from the results shown in Tables 6 and 7, the polyolefin resin composition of the present invention (Sample No.
Nos. 1 to 7) have a small surface specific resistance value and excellent antistatic properties without deteriorating the physical properties of the resin. Also,
Even after washing with water, there is almost no change in the value, and the permanent antistatic performance is excellent. On the other hand, the polyolefin resin compositions (Sample Nos. 8 to 16) outside the scope of the present invention are inferior in any of physical properties, antistatic properties, and permanent antistatic properties.

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Claims (1)

[Claims] 1. A) 100 parts by weight of a polyolefin resin, b) 1 to 50% by weight of a monomer having a sulfonic acid group,
1 to 50% by weight of a (meth) acrylate monomer having a polyoxyalkylene chain and 20 to 98% by weight of a (meth) acrylate monomer having an alkyl group having 12 to 22 carbon atoms
And 1 to 50 parts by weight of a copolymer having a weight average molecular weight of 5,000 to 500,000 obtained by copolymerizing a monomer mixture consisting of 0 to 70% by weight of another copolymerizable monomer. A polyolefin resin composition characterized in that it does not exist.