JP7280029B2 - Antistatic agent for polyolefin resin and polyolefin resin composition containing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to an antistatic agent for polyolefin resins, and more particularly, it does not impair the initial antistatic properties, generates less smoke due to the antistatic agent and its decomposition products during molding, and prevents roll contamination due to accumulation of volatiles. The present invention relates to an antistatic agent suitable for obtaining a polyolefin resin composition excellent in antistatic properties and antifogging properties, and a polyolefin resin composition containing the antistatic agent.

Polyolefin films are widely used in many fields including packaging materials because they are excellent in transparency, moisture resistance, mechanical strength, etc., and are inexpensive. However, since the film has a high electrical resistivity and is easily electrified, there is a tendency for dust and dirt to adhere to the surface of the film due to static electricity, thereby reducing the value of packaging materials and the like.

As one of the methods for solving the above problems, there is a method of adding an antistatic agent to a polyolefin film and bleeding the antistatic agent onto the polyolefin film surface to impart antistatic properties to the film surface. has been used. For example, as antistatic agents for biaxially oriented polypropylene (OPP) films, conventionally, glycerol fatty acid esters and aliphatic diethanolamine fatty acid esters are used in combination (see Patent Document 1).

However, the glycerin fatty acid ester and the aliphatic diethanolamine fatty acid ester undergo an ester exchange reaction easily when they are heated and melted, or when the masterbatch or film is molded, and glycerin is released from the glycerin fatty acid ester. The free matter emits smoke due to heat during molding, and is deposited on the die and rolls of the extruder, or in the tenter, etc., and adheres to the film, causing poor quality.

In order to solve these problems, antistatic agents containing diglycerin fatty acid esters and polyglycerin fatty acid esters as main components have been proposed (see Patent Documents 2 and 3). However, they are less likely to migrate to the surface of the film than glycerin fatty acid esters, and are inferior in immediate antistatic effect, so that a certain amount of glycerin fatty acid esters must be used in combination.
In addition, there is also the problem that the composition of the antistatic agent changes over time, impairing the durability of the antistatic effect and the antifogging property.

Therefore, it has been desired to develop an antistatic agent that contains almost no free substances until the time of molding, and to develop a polyolefin resin composition that reduces molding defects due to deposits without impairing the initial antistatic properties.

Japanese Patent Publication No. 60-57461 JP-A-9-3273 Japanese Unexamined Patent Application Publication No. 2002-47485

An object of the present invention is to solve the problems in the prior art as described above, and to provide an antistatic agent that does not impair the antistatic property in the early stage after molding and hardly generates smoke during molding. It is an object of the present invention to provide a polyolefin resin composition having excellent antifogging properties by using the antistatic agent.

As a result of intensive studies to solve the above problems, the inventors of the present invention found that by blending fatty acid monoesters and fatty acid amides of polyoxyethylene alkylamine or polyoxyethylene alkenylamine with polyolefin resin, The inventors have found that a polyolefin-based resin composition that does not emit smoke and has excellent antistatic properties immediately after molding can be obtained, leading to the completion of the present invention.

（式中、Ｒ^１は炭素数８～２２のアルキル基又はアルケニル基、Ｒ^２は炭素数７～２１のアルキル基又はアルケニル基を示し、ｍ、ｎは、ｍ＋ｎ＝２～５となる整数を示す。）
及び、
（Ｂ）：脂肪酸アミド
［２］成分（Ａ）と成分（Ｂ）の質量比が、（Ａ）／（Ｂ）＝１０／９０～９９／１である、［１］に記載のポリオレフィン系樹脂用帯電防止剤。
［３］グリセリン脂肪酸エステルを含まない、［１］又は［２］に記載のポリオレフィン系樹脂用帯電防止剤。
［４］ポリオレフィン系樹脂と、［１］又は［２］に記載の帯電防止剤を含有する、ポリオレフィン系樹脂組成物。
［５］ポリオレフィン樹脂１００質量部に対し、請求項１又は２に記載の帯電防止剤を０．１～１．５質量部含有する、ポリオレフィン系樹脂組成物。
［６］［４］又は［５］に記載のポリオレフィン系樹脂組成物からなるフィルム。 That is, the present invention provides the following.
[1] An antistatic agent for polyolefin resins comprising the following components (A) and (B).
(A): Fatty acid monoester of polyoxyethylene alkylamine or polyoxyethylene alkenylamine represented by the following general formula (1)

(In the formula, R ¹ represents an alkyl or alkenyl group having 8 to 22 carbon atoms, R ² represents an alkyl or alkenyl group having 7 to 21 carbon atoms, and m and n are integers such that m + n = 2 to 5. show.)
as well as,
(B): Fatty acid amide [2] The polyolefin resin according to [1], wherein the mass ratio of component (A) to component (B) is (A)/(B) = 10/90 to 99/1. Antistatic agent for.
[3] The antistatic agent for polyolefin resins according to [1] or [2], which does not contain a glycerin fatty acid ester.
[4] A polyolefin resin composition containing a polyolefin resin and the antistatic agent according to [1] or [2].
[5] A polyolefin resin composition containing 0.1 to 1.5 parts by mass of the antistatic agent according to claim 1 or 2 with respect to 100 parts by mass of the polyolefin resin.
[6] A film made of the polyolefin resin composition according to [4] or [5].

The antistatic agent of the present invention hardly generates smoke during molding of the polyolefin resin composition containing it, and exhibits excellent antistatic effect immediately after molding even without using glycerin fatty acid ester, In addition, there is an effect that excellent anti-fogging properties can be imparted.

（式中、Ｒ^１は炭素数８～２２のアルキル基又はアルケニル基、Ｒ^２は炭素数７～２１のアルキル基又はアルケニル基を示し、ｍ、ｎは、ｍ＋ｎ＝２～５となる整数を示す。）
及び、
（Ｂ）：脂肪酸アミド
ポリオレフィン系樹脂に本発明の帯電防止剤を配合することにより、成形時の発煙がなく、成形直後から帯電防止性に優れるポリオレフィン系樹脂組成物が得られる。このような効果が得られる理由の詳細は不明であるが、帯電防止効果の高いアミンエステル化合物（Ａ）のフィルム表面への移行を脂肪酸エステル（Ｂ）が促進する効果があるためと推定される。 The present invention will be described in detail below.
The antistatic agent for polyolefin resins of the present invention contains the following component (A) and component (B).
(A): fatty acid monoester of polyoxyethylene alkylamine or polyoxyethylene alkenylamine represented by the following general formula (1) (hereinafter also referred to as "amine ester compound (A)");

(In the formula, R ¹ represents an alkyl or alkenyl group having 8 to 22 carbon atoms, R ² represents an alkyl or alkenyl group having 7 to 21 carbon atoms, and m and n are integers such that m + n = 2 to 5. show.)
as well as,
(B): Fatty acid amide By blending the antistatic agent of the present invention with a polyolefin resin, it is possible to obtain a polyolefin resin composition that does not emit smoke during molding and has excellent antistatic properties immediately after molding. Although the details of the reason why such an effect is obtained are unknown, it is presumed that the fatty acid ester (B) has the effect of promoting the migration of the amine ester compound (A), which has a high antistatic effect, to the film surface. .

<Amine ester compound (A)>
The amine ester compound (A) used in the present invention is a fatty acid monoester of polyoxyethylenealkylamine or polyoxyethylenealkenylamine.
Polyoxyethylene alkylamines or polyoxyethylene alkenylamines include polyoxyethylene laurylamine, polyoxyethylene myristylamine, polyoxyethylene palmitylamine, polyoxyethylene stearylamine, polyoxyethylene oleylamine.
Among them, from the viewpoint of obtaining a good antistatic effect, m and n in the general formula (1) are preferably amine ester compounds in which m + n = 2 to 3, and amine ester compounds in which m + n = 2, specifically lauryldiethanolamine. , myristyldiethanolamine, palmityldiethanolamine, stearyldiethanolamine, and oleyldiethanolamine are more preferable, and stearyldiethanolamine is particularly preferable.
Fatty acids include fatty acids having 8 to 22 carbon atoms, such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid and behenic acid.

Specific examples of the amine ester compound (A) include lauryl diethanolamine monostearate, myristyl diethanolamine monooleate, palmityl diethanolamine monostearate, stearyl diethanolamine monolaurate, stearyl diethanolamine monostearate, stearyl diethanolamine monooleate, stearyldiethanolamine monobehenate, oleyldiethanolamine monostearate and the like. These amine ester compounds (A) may be used individually by 1 type, and may be used in combination of 2 or more type.

Although the method for producing the amine ester compound (A) is not particularly limited, fatty acid and can be produced by a method of esterification by dehydration reaction at a temperature of 190 to 230° C., or by a method of transesterification with fatty acid methyl ester. The amine ester compound (A) may contain unreacted polyoxyethylene alkylamine or polyoxyethylene alkenylamine, or a diester compound as long as the object of the present invention is not impaired.

<Fatty acid amide (B)>
Examples of the fatty acid amide (B) include lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, oxystearic acid amide, oleic acid amide, erucic acid amide, linoleic acid amide, and ricinoleic acid amide. , ethylene bis stearamide, methylene bis stearamide, methylene bis stearobehenamide, ethylene bis oleate amide, methylene bis oleate amide and the like. These fatty acid amides (B) may be used singly or in combination of two or more.

In the antistatic agent of the present invention, the mass ratio of the amine ester compound (A) and the fatty acid amide (B) is (A)/( B)=10/90 to 99/1 is preferred, 30/70 to 90/10 is more preferred, and 50/50 to 80/20 is particularly preferred.

<Other ingredients>
The antistatic agent of the present invention may contain components other than the amine ester compound (A) and the fatty acid amide (B) as long as the objects of the present invention are not impaired. For example, polyoxyethylene alkylamines and polyoxyethylene alkenylamines remaining as unreacted raw materials of the amine ester compound (A), fatty acid diesters, polyhydric alcohol fatty acid esters, and alkyldiethanolamines that are by-produced during the synthesis of the amine ester compound (A). , nonionic surfactants, anionic surfactants, cationic surfactants, and other known antistatic agents. When a diglycerin fatty acid ester is used in combination, the glycerin fatty acid ester may be contained as an impurity, but in view of the object of the present invention, the content is 1% by mass or less in the total amount of the antistatic agent of the present invention. It is preferable that there is, and it is more preferable that it does not substantially contain.

The polyolefin resin used in the polyolefin resin composition of the present invention is not particularly limited, and known resins are used. For example, homopolymers of α-olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, copolymers of the α-olefins, and the α-olefins They include copolymers of monomers other than copolymerizable α-olefins and α-olefins, and mixtures thereof.
Specifically, low-density polyethylene, high-density polyethylene, polypropylene, propylene-ethylene copolymer, propylene-butene copolymer, propylene-ethylene-butene copolymer, ethylene/butene-1 copolymer, ethylene/propylene · Butene-1 copolymer, ethylene/acrylic acid copolymer, ionomer obtained by cross-linking ethylene/acrylic acid copolymer with metal ions, polybutene-1, and butene/ethylene copolymer. You may use these individually or in mixture of 2 or more types.
Examples of monomers other than the α-olefin that can be copolymerized with the α-olefin include vinyl acetate, maleic acid, vinyl alcohol, methacrylic acid, methyl methacrylate, and ethyl methacrylate.

The content of the antistatic agent of the present invention contained in the polyolefin resin composition is 0.1 per 100 parts by mass of the polyolefin resin, from the viewpoint of imparting an excellent antistatic effect to the polyolefin resin composition. It is preferably in the range of up to 1.5 parts by mass. A preferred range for the content of the surfactant composition is 0.5 to 1.5 parts by mass. Within this range, particularly excellent antistatic properties can be provided.

A polyolefin resin composition is prepared by mixing a polyolefin resin, an amine ester compound (A) and a fatty acid amide (B ) can be obtained by heating and kneading. Although (A) and (B) may be added to the polyolefin resin separately, it is preferable to mix them in advance and then add them to the polyolefin resin because the antistatic effect can be obtained quickly. If the amounts of (A) and (B) added relative to the amount of the polyolefin resin are small, it will be difficult to uniformly disperse them in the resin. For this reason, a masterbatch method is adopted in which a masterbatch containing (A) and/or (B) at a high concentration is prepared in advance and kneaded with a polyolefin resin containing no antistatic agent to obtain a predetermined content. is preferred.

Various additives commonly used in polyolefin resin compositions can be added to the polyolefin resin composition as long as they do not impair the object of the present invention. Examples of various additives include antifogging agents, antioxidants, weathering agents, ultraviolet absorbers, stabilizers, slip agents, tackifiers, antiblocking agents and the like.

A film obtained by molding the polyolefin resin composition of the present invention is also one of the embodiments of the present invention. Examples of the method for producing a polyolefin film include a T-die method, an inflation method, a calender method, etc. Among them, the T-die method, in which a T-die is used to melt-knead and extrude, is preferred. As an example of the T-die method, the polyolefin resin composition is supplied to an extruder hopper, the extruder is heated to a cylinder temperature of 180 to 240 ° C. and a T-die temperature of 200 to 230 ° C., melt-kneaded and extruded. , with a cooling roll controlled at 20 to 40° C. to obtain an unstretched sheet having a thickness of 100 to 500 μm. For the purpose of imparting strength and other functions to the film, a co-extrusion method and lamination with other films can be used to form a multilayer.

As a method for biaxially stretching the unstretched sheet, any of a simultaneous biaxially stretching method using a tenter system and a sequential biaxially stretching method using rolls and a tenter may be used. As a representative example of simultaneous biaxial stretching, the unstretched sheet obtained as described above is stretched to a surface ratio of 9 to 16 times with a tenter having a preheating/stretching temperature of 70 to 90° C. and a heat setting temperature of 100 to 150° C. to obtain a film. get Further, as a typical example of sequential biaxial stretching, an unstretched sheet is stretched in the longitudinal direction at a roll surface temperature of 50 to 80° C. and a stretch ratio of 1.5 to 5 times depending on the rotation speed ratio of the driving rolls, and then continuously stretched. A film is obtained by stretching in the transverse direction under conditions of a stretching temperature of 50 to 90°C, a stretching ratio of 1.5 to 8 times, and a heat setting temperature of 100 to 150°C.

The thickness of the polyolefin-based film according to the present invention is not particularly limited, and may be appropriately set depending on the application, required performance, price, and the like. Generally, a thickness of about 10 to 100 μm can be exemplified. Furthermore, the film may be surface-treated for the purpose of improving the printability, laminateability, coating suitability, and the like of the film. Examples of surface treatment methods include corona discharge treatment, plasma treatment, and acid treatment, and any method can be used. Among these, corona discharge treatment can be exemplified as the most preferable treatment in terms of simplicity.

Moreover, the polyolefin-based resin composition of the present invention can also be molded into any moldings such as sheets, bottles, filaments, and injection-molded articles.

EXAMPLES The present invention will be described in more detail below based on examples, but the present invention is not limited to these. Unless otherwise specified, the blending amount is shown in parts by mass.

Measurement and evaluation of each evaluation item were performed by the following methods.
(1) Smoke emission during film formation The state of smoke emission from the extruder, tenter outlet and exhaust port of the film forming machine during film formation was visually observed.
〇・・・Smoking hardly confirmed ×・・・Smoking confirmed

(2) Antistatic property Immediately after film formation and after aging at 45 ° C. for 24 hours, the film was subjected to a high resistance insulation tester (Mitsubishi Chemical Analytech Co., Ltd., Hiresta UP MCP- HT450), the film was sandwiched between the main electrode and the counter electrode, and the surface resistivity was measured at an applied voltage of 500 V according to JIS-K-6911.

(3) Anti-fogging property
100 ml of water is placed in a 200 ml beaker, the film after aging in (2) above is placed on the beaker, fixed with a rubber band, and stored in a constant temperature machine (5° C., 20° C.) for 30 minutes.
After that, a piece of paper on which letters were written was placed under the beaker, and it was observed to what degree the film surface and the letters placed below were visible.
◯: The film surface is uniformly wetted, and the letters underneath are clearly visible.
Δ: The surface of the film is unevenly wetted, and the characters below appear to be blurred.
x: Fine water droplets are present on the entire surface of the film, and letters cannot be seen.

(4) Phase Separation of Antistatic Agent Mixture A mixture of antistatic agents shown in Tables 1-1 and 1-2 was placed in a 200 ml bottle, stored at 80° C. for 24 hours, and then its appearance was checked.
None: no phase separation.
Yes: Phase separation occurs.

Example 1
To 100 parts of a homopolypropylene resin having a melt flow rate of 3.0 g/10 minutes, 0.95 parts of premixed stearyldiethanolamine monolaurate and 0.05 parts of stearic acid amide were added and mixed with a Henschel mixer. Melt-kneading was performed using a twin-screw extruder equipped with a pelletizer to obtain a polypropylene resin composition in the form of pellets.

After T-die molding from the obtained polypropylene resin composition, it was successively biaxially stretched to form a film to obtain a film having a thickness of 30 μm. The surface resistivity and antifogging properties of the resulting film were measured and evaluated according to the methods described above. These results are shown in Table 1-1.

Examples 2-11
Films were produced and evaluated in the same manner as in Example 1, except that the type and amount of the antistatic agent were as shown in Table 1-1. The results are shown in Table 1-1.

Comparative example 1
To 100 parts of a homopolypropylene resin having a melt flow rate of 3.0 g/10 minutes, 0.7 parts of premixed stearyldiethanolamine monostearate and 0.3 parts of glycerin monostearate were added and mixed with a Henschel mixer. , melt-kneaded using a twin-screw extruder equipped with a pelletizer to obtain a polypropylene resin composition in the form of pellets.

After T-die molding from the obtained polypropylene resin composition, it was successively biaxially stretched to form a film to obtain a film having a thickness of 30 μm. The surface resistivity and antifogging properties of the resulting film were measured and evaluated according to the methods described above. These results are shown in Table 1-2.

Comparative Examples 2 and 3
In Comparative Example 1, films were produced and evaluated in the same manner as in Comparative Example 1, except that the type and blending amount of the antistatic agent were as shown in Table 1-2. The results are shown in Table 1-2.

As shown in Table 1-1, the polypropylene resin compositions of Examples 1 to 11 containing the antistatic agent of the present invention hardly emit smoke during film formation, and have excellent antistatic properties immediately after film formation. It was something. In addition, the antifogging property was also good.
On the other hand, as shown in Table 1-2, the polypropylene resin compositions of Comparative Examples 1 and 2 in which glycerin fatty acid ester was used in combination gave off smoke during film formation. Moreover, phase separation of the antistatic agent mixture was observed, and it was confirmed that the separated product was glycerin. On the other hand, the polypropylene resin composition of Comparative Example 3 to which only the amine ester compound (A) was added did not emit smoke during film formation, but was inferior in antistatic properties immediately after film formation.

Claims (2)

An antistatic agent mixture for polyolefin resins containing the following components (A) and (B) and substantially free of glycerin fatty acid ester .
(A): Fatty acid monoester of polyoxyethylene alkylamine or polyoxyethylene alkenylamine represented by the following general formula (1)

(In the formula, R ¹ represents an alkyl or alkenyl group having 8 to 22 carbon atoms, R ² represents an alkyl or alkenyl group having 7 to 21 carbon atoms, and m and n are integers such that m + n = 2 to 5. show.)
as well as,
(B): fatty acid amide 2. The antistatic agent mixture for polyolefin resin according to claim 1, wherein the mass ratio of component (A) and component (B) is (A)/(B)=10/90 to 99/1.