JPH0649735B2 - Novel ethylene copolymer and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel ethylene copolymer and a method for producing the same.

More specifically, the present invention relates to a copolymer of ethylene and ε-caprolactone modified vinyl monomer and a method for producing the copolymer by a high pressure radical polymerization method.

<Prior art> Polyethylene and various ethylene copolymers have excellent characteristics such as easy moldability, high strength and elongation, flexibility and chemical resistance, and are suitable for packaging films and molded products. Is widely used for various purposes. However, since they are easily charged with electricity, they have problems such as the appearance of dirt due to the adhesion of dust or dust, the influence of accumulated static electricity on the human body (electric shock), and spark discharge.

Therefore, antistatic properties have been improved by adding nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants as antistatic agents to polyethylene and various ethylene copolymers. However, with the addition of an antistatic agent, the antistatic durability and
There is a problem that the surface of the film or molded product becomes sticky and the slipperiness deteriorates.

<Problems to be Solved by the Invention> An object of the present invention is to solve the above problems and to provide ethylene and ε-caprolactone-modified vinyl monomer excellent in permanent antistatic property, and optionally other ethylenically unsaturated monomer. It is intended to provide a novel ethylene copolymer comprising a polymer and a method for producing the same.

<Means for Solving Problems> In the present invention, 40 to 97% by weight of ethylene units and 60 to 3% by weight of one or more ε-caprolactone-modified vinyl monomer units represented by the general formula (A) are used. , And 0 to 40% by weight of one or more ethylenically unsaturated monomer units selected from unsaturated carboxylic acids, unsaturated carboxylic acid alkyl esters and vinyl esters of saturated carboxylic acids, and melted Index (JIS K6760) is 0.1-500gr / 1
The present invention relates to a novel ethylene copolymer characterized by being 0 minutes.

Further, 40 to 97% by weight of ethylene, 60 to 3% by weight of one or more ε-caprolactone modified vinyl monomers represented by the general formula (A), and an unsaturated carboxylic acid,
In the presence of a radical polymerization initiator, a mixture containing 0 to 40% by weight of one or more ethylenically unsaturated monomers selected from unsaturated carboxylic acid alkyl ester and saturated carboxylic acid vinyl ester is selected. 500-3,000Kg / cm ²
And a melting index (JIS K6760) characterized by being copolymerized under the conditions of pressure of 100 to 300 ° C and 0.1 to 50.
The present invention relates to a method for producing a novel ethylene copolymer having 0 gr / 10 minutes.

(Here, R ₁ is H or an alkyl group, R ₂ is C
_m H _2m , m is an integer of 2 or more, and n is a number of 0.3 to 5 on average. ) Hereinafter, the content of the present invention will be described in detail.

The ε-caprolactone-modified vinyl monomer unit used in the present invention has the general formula (A) R ₁ is H or an alkyl group, more preferably H or CH ₃ , and R ₂ is CmH _2m (m is 2
The above integers, more preferably 2 or 3 or 4), and n are 0.3 to 5 are exemplified. Specific examples thereof include an ε-caprolactone adduct of hydroxyethyl (meth) acrylate.

The ε-caprolactone-modified vinyl monomer is produced by reacting a hydroxyalkyl (meth) acrylic acid ester with ε-caprolactone in the presence of a catalyst such as stannous halide at a reaction temperature of 80 to 150 ° C.

The ε-caprolactone-modified vinyl monomer imparts hydrophilicity to the ethylene copolymer in terms of antistatic property. The content of ε-caprolactone modified vinyl monomer unit is 3 to 60% by weight, preferably 5 to 60% by weight, more preferably 15 to
50% by weight is suitable. If the content is 3% by weight or less, it becomes difficult to obtain the above characteristics. Further, if the content is 60% by weight or more, the production amount of a low molecular weight copolymer lacking toughness and flexibility increases, which is not preferable.

Other ethylenically unsaturated monomer units used in the present invention include methyl acrylate, methyl methacrylate, ethyl acrylate, n-butyl acrylate, glycidyl acrylate and glycidyl methacrylate. Examples thereof include acid esters, ethylenic vinyl esters such as vinyl acetate and propionate bivinyl, and ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride and fumaric acid. Among them, preferred are methyl acrylate, methyl methacrylate, ethyl acrylate, n-butyl acrylate and vinyl acetate. Particularly preferred are methyl acrylate, ethyl acrylate, methyl methacrylate and vinyl acetate. The content of the ethylenically unsaturated monomer is 0 to 40% by weight, preferably 0 to 30% by weight, more preferably 0 to 20% by weight.

On the other hand, the method for producing the ethylene copolymer of the present invention comprises 40 to 97% by weight of ethylene, 3 to 60% by weight of the ε-caprolactone-modified vinyl monomer represented by the general formula (A), and other ethylenic compounds. It relates to a method of copolymerizing a mixture containing a saturated monomer in a proportion of 0 to 40% by weight in the presence of a radical polymerization initiator under certain conditions.

The copolymerization reaction for producing the ethylene copolymer is 50
Can be carried out at a pressure of 0~3,000kg / cm ^2, pressure is preferably 700~2,500kg / cm ^2. The temperature is generally 100 ~
It can be performed at 300 ℃, but the preferred temperature is 150-250
℃. When the pressure is 500 kg / cm ² or less or the temperature is 100 ° C. or less, the polymerization reaction rate and the conversion rate are significantly decreased, and a large amount of a polymerization initiator is required, which is industrially disadvantageous. Occasionally, a low molecular weight substance lacking toughness and flexibility is produced, which is not preferable. Also pressure
At a high pressure of 3,000 kg / cm ² or higher or a high temperature of 300 ° C or higher, the polymerization operation becomes difficult, and safe operation cannot be expected. The method according to the present invention is a batch method,
A method such as a semi-continuous type or a continuous type can be adopted.

The radical polymerization initiator for initiating the copolymerization reaction means an initiator that generates a radical under the polymerization conditions adopted, and may be oxygen, —O—O— bond or —N═.
A compound having an N-bond and the like are included. Such catalysts include oxygen, hydrogen peroxide, peroxides, azo compounds and the like, among which the general formula X-O-Y type, (In the formula, X is an aralkyl group and its derivative group, an aryl group, an alkyl group, etc., Y is an aryl group and its derivative group, an aralkyl group, an alkyl group, water, etc., and X and Y are the same or different. Peroxide powder and azo compound represented by the formula (1) are particularly effective. Specific examples of the compound include diethyl peroxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyacetate, tert-butyl peroxy- 2-ethylhexanoate, tert-butyl peroxypivalate, 2-ethylhexanoyl oxide,
Organic peroxides such as pivalyl peroxide, isopropyl peroxydicarbonate and azobisisobutyronitrile, azobis-2,2-diphenylacetonitrile, 1-tert-butylazo-1-cyanocyclohexane, 2-tert-butylazo Examples thereof include one or a mixture of two or more azo compounds such as 2-cyanopropane and 2-tert-butylazo-2-cyanobutane.

The amount used is 5 to 3,000 parts by weight with respect to 1 million parts by weight of ethylene.

The polymerization modifier is used as necessary, but an ordinary one is appropriately used. For example, ethane, propane, propylene, butene-1, isobutene, hexane and heptane can be used particularly effectively.

The amount used is 0.1 to 10 parts by weight based on 100 parts by weight of ethylene.

Melt index is 0.1 to 500 g / 10 min, preferably 1.0 to 3
It is adjusted with a polymerization modifier so that it becomes 00 g / 10 minutes. When the melting index is 0.1 g / 10 minutes or less, workability is lowered and it is industrially disadvantageous. Further, if the melting index is 500 g / 10 minutes or more, problems such as bleeding of low molecular weight products may occur, which is not preferable.

In addition, in the present invention, the intrinsic viscosity (measured by tetralin) of the obtained copolymer is from 0.5 to 1.0 d.
l / g. When the intrinsic viscosity is less than 0.5 to dl / g, problems such as bleeding of low molecular weight products occur, and 1.0 dl / g
If it exceeds, the workability is deteriorated, which is not preferable. Preferably,
It is 0.55 to 0.85 dl / g.

The ethylene copolymer of the present invention is suitable for molded articles, films, coatings and bonding agents, and is particularly excellent in antistatic property and hygroscopic property. It is also blended with other polyolefins to provide useful polyolefin compositions.

If desired, stabilizers, pigments, fillers and other additives can be mixed with the ethylene copolymer of the present invention and the polyolefin composition using the same.

<Examples> Next, the present invention will be described with reference to Examples, but the present invention is not limited thereto.

Example 1 Using a stirred autoclave type continuous reactor having an internal volume of 2 liters, ethylene was added at 15.9 kg / hr as shown in Table 1.
A 80% by weight methanol solution of hydroxyethyl methacrylate in which ε-caprolactone was added to an average of 1.5 mol was added.
0.57 Kg / hr, using a 0.4 wt% isoparaffin solution of tertiary butyl peroxypivalate as a polymerization initiator 57
Polymerization pressure 1700Kg / c, continuously supplied at a rate of 0g / hr
A copolymer was produced at m ² and a polymerization temperature of 175 ° C.

As shown in Table 1, the obtained ethylene copolymer had a melting index (JIS K6760) of 1.3 g / 10 minutes, an intrinsic viscosity (135 ° C., tetralin) of 0.85 dl / g, and ε-caprolactone of 1.
The content of hydroxyethyl methacrylate (hereinafter referred to as A comonomer) added by 5 mol (by elemental analysis) was 42% by weight.

Also, this ethylene copolymer was dissolved in xylene, reprecipitated with methanol and washed, and the melting index was 0.9 g / 10.
The content of comonomer A is 40% by weight, and it is clear that substantially all of the copolymer is a copolymer with ethylene.

A sheet of 300 microns was made from this ethylene copolymer using a 100 mm T-die molding machine, and the surface resistivity (23 ° C, 50% in a constant temperature and humidity chamber) immediately after molding and after 1 month was calculated by Toa Denpa SM Table 2 shows the results of evaluation with an applied voltage of 10 V using a -10E type ultra-insulation meter.

Example 2 Instead of the A comonomer of Example 1, hydroxyethyl methacrylate (hereinafter referred to as B comonomer) to which ε-caprolactone was added in an average of 3 mol was used. Table 1 shows the copolymerization conditions and the properties of the obtained ethylene copolymer.

The ethylene copolymer was dissolved in xylene, reprecipitated with methanol and washed, and the melting index was 18 g / 10 min.
The comonomer content is 21% by weight, and it is clear that it is essentially a copolymer with ethylene.

The ethylene copolymer was processed in the same manner as in Example 1 and evaluated. The results are shown in Table 2.

Example 3 Methyl methacrylate (hereinafter referred to as MMA) was used as the A comonomer of Example 1 and other ethylenically unsaturated monomers. Table 1 shows the copolymerization conditions and the properties of the obtained ethylene copolymer.

The ethylene copolymer was processed in the same manner as in Example 1 and evaluated. The results are shown in Table 2.

Comparative Example 1 Using Table 1 and Table 2, the results of evaluation by copolymerization reaction using A comonomer as in Example 1 are shown.

Comparative Examples 2 and 3 Polyethylene (Sumitomo Chemical Co., Ltd.): Sumikase
The L705) and MMA content 30% by weight, melt index 9.
Same as Example 1 using 1 g / 10 min ethylene copolymer
The results evaluated in Table 2 are shown in Table 2.

<Effects of the Invention> As described above, according to the present invention, a novel ethylene comprising ethylene excellent in permanent antistatic property, ε-caprolactone-modified vinyl monomer, and, in some cases, other ethylenically unsaturated monomer. A copolymer and a method for producing the same can be provided.

The ethylene copolymer of the present invention has an excellent antistatic effect while retaining the original moldability, high strength and elongation, flexibility and chemical resistance inherent to polyethylene. Also,
Since the antistatic effect is maintained over a long period of time, its application range is extremely large compared to conventional polyethylene with an antistatic effect.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noboru Yamaguchi 1-5 Anesaki Kaigan, Ichihara, Chiba Prefecture Sumitomo Chemical Co., Ltd. (72) Mitsuyuki Okada 1-5 Anezaki Kaigan, Ichihara, Chiba Sumitomo Chemical Co., Ltd. (72) Inventor Michio Nakanishi 5-12-19 Owada, Niiza City, Saitama Prefecture (72) Inventor Takuya Miho 6-8-2 Kuba, Otake City, Hiroshima Prefecture (56) Reference JP-A-52-126495 (JP) , A)

Claims (4)

[Claims] 1. An ethylene unit in an amount of 40 to 97% by weight, one or more ε-caprolactone-modified vinyl monomer units represented by the general formula (A) in an amount of 60 to 3% by weight, and an unsaturated carboxylic acid, One or more ethylenically unsaturated monomer units selected from saturated carboxylic acid alkyl esters and saturated carboxylic acid vinyl esters are used.
-40% by weight, melting index (JIS K6760) is 0.1
A novel ethylene copolymer characterized by being 500 gr / 10 minutes. (Here, R ₁ is H or an alkyl group, R ₂ is C
_m H _2m , m is an integer of 2 or more, and n is a number of 0.3 to 5 on average. ) 2. The novel ethylene according to claim 1, wherein the ethylenically unsaturated monomer is a monomer selected from the group consisting of methyl acrylate, ethyl acrylate, methyl methacrylate and vinyl acetate. Copolymer. 3. An ethylene unit in an amount of 40 to 97% by weight, an ε-caprolactone-modified vinyl monomer unit represented by the general formula (A) in an amount of 60 to 3% by weight, and an unsaturated carboxylic acid, One or more ethylenically unsaturated monomer units selected from saturated carboxylic acid alkyl esters and saturated carboxylic acid vinyl esters are used.
The melting index (JIS) is characterized by copolymerizing a mixture containing 40 to 40% by weight in the presence of a radical polymerization initiator under the conditions of a pressure of 500 to 3,000 kg / cm ² and a temperature of 100 to 300 ° C. K6760) is a method for producing a novel ethylene copolymer having a content of 0.1 to 500 gr / 10 minutes. (Here, R ₁ is H or an alkyl group, R ₂ is C
_m H _2m , m is an integer of 2 or more, and n is a number of 0.3 to 5 on average. ) 4. The novel ethylene according to claim 3, wherein the ethylenically unsaturated monomer is a monomer selected from the group consisting of methyl acrylate, ethyl acrylate, methyl methacrylate and vinyl acetate. Method for producing copolymer.