JP2018044053A - Flame-retardant film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyethylene-based flame-retardant film which has high flameproof performance (JIS flameproof first grade) and has high strength and high transparency, and has no environmental problem.SOLUTION: A polyethylene-based flame-retardant film is obtained by film formation of a resin composition which contains 45-80 wt.% of a copolymer of ethylene and α-olefin having 3 to 12 carbon atoms and 20-55 wt.% of a high-pressure radical method polyethylene-based resin, and contains 100 pts.wt. of a polyethylene-based resin having (1) to (2) features and 0.8-4.0 pts.wt. of an alkoxyimino group type hindered amine-based compound; and has characteristics (a) to (d).SELECTED DRAWING: None

Description

  The present invention relates to a polyethylene-based flame retardant film, and in particular, excellent flame retardancy, high strength and high strength obtained by using a resin raw material in which a specific resin and a specific flame retardant are combined for film molding. The present invention relates to a film having transparency.

  Conventionally, in construction sites with painting, construction sites using fire, or painting under highway piers, a curing film covering the periphery of the site has been used to prevent diffusion of coating agents or sparks It has been. This curing film is required to have a highly transparent film in order to secure the field of view around the work site and to ensure the daylighting of the work site itself. Furthermore, there is a demand for strength that can withstand tearing due to contact with various equipment used in the field or severe handling, and vinyl chloride films, polyethylene films, and the like have been used.

  In recent years, in order to ensure the safety of these curing films in the field accompanied by fire, it has been demanded that the films used be flame-retardant. Although a vinyl chloride film originally having high flame retardancy has no problem, a polyethylene film is inferior in flame retardancy and its improvement is strongly demanded. Although there is no problem with the flame retardancy of vinyl chloride film, there are problems such as the generation of harmful gases such as hydrogen chloride by depreciation after disposal, and its use is being restricted due to environmental considerations.

  On the other hand, various studies have been made on the flame retardancy of polyethylene films, and in general, chlorinated paraffins, chlorinated polyphenols, perchlorpentacyclodecane, and the like that are easy to impart flame retardancy performance at a relatively low cost. Flame retardants and brominated flame retardants such as ethylene bispentabromodiphenyl, tetrabromoethane, tetrabromobisphenol A, hexabromobenzene, hexabromocyclododecane and decabromobiphenyl ether have been used. However, these halogen-based flame retardants have environmental problems such as the fact that some of them are designated as monitoring chemicals due to the risk of non-decomposability and high concentration. It is being done.

  In view of the above situation, non-halogen flame retardants have recently attracted attention as an alternative to halogen flame retardants. For example, polyolefin resin made flame retardant by adding inorganic substances such as magnesium hydroxide or aluminum hydroxide (Patent Document 1), or metal hydroxide and antimony trioxide added to linear low density polyethylene However, flame retardant (Patent Document 2) and the like have been proposed. However, these inorganic flame retardants require a relatively large amount of addition to ensure flame retardancy, resulting in problems such as greatly reducing the strength of the film and inability to ensure transparency of the film. was there.

JP 2009-102554 A JP 2007-204653 A

  In view of the above-mentioned problems of the prior art, an object of the present invention is a polyethylene having high flameproof performance (JIS flameproof grade 1), high strength and high transparency, and no problem with the environment. It is to provide a flame retardant film.

  As a result of intensive studies to solve the above problems, the present inventors have determined that a polyethylene-based copolymer containing a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms and a high-pressure radical method polyethylene-based resin in a specific ratio. The resin has specific physical properties, and by blending a specific amount of a specific hindered amine compound with the polyethylene resin, excellent flameproof performance (JIS flameproof grade 1) in a specific film thickness range. It has been found that a film having high strength and transparency and having no environmental problems can be obtained, and the present invention has been completed.

That is, the present invention
[1] 45 to 80% by weight of a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms, and 20 to 55% by weight of a high-pressure radical polyethylene resin, and the following (1) to (2) 100 parts by weight of polyethylene resin having characteristics (1) MFR (melt flow rate measured at 190 ° C. and 21.18 N load) is 0.5 to 4.0 g / 10 minutes (2) Density is 0.905 0.935 g / cm ³
And a film obtained by forming a resin composition containing 0.8 to 4.0 parts by weight of an alkoxyimino group-type hindered amine compound, and having the following characteristics (a) to (d) Polyethylene flame retardant film.
(A) The thickness of the film is 25 to 95 μm
(B) In a flameproof test based on JIS A1322, the flame haze value is 15% or less based on JIS K7106, which is a flameproof grade 1 (d) Puncture impact strength based on JIS P8134 is 0.6 J or more It is.
[2] The copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms is a copolymer polymerized by a single site catalyst such as a metallocene catalyst. Polyethylene flame retardant film.
[3] A curing film comprising the flame retardant film according to [1] or [2].
Is provided.

  The polyethylene-based flame retardant film of the present invention has excellent flameproof performance in a specific film thickness range and high strength by blending a specific amount of a specific polyethylene-based resin and a specific flame retardant. It is also excellent in an environment that maintains high transparency.

1. Polyethylene Flame Retardant Film The polyethylene flame retardant film of the present invention (hereinafter also referred to as “the film of the present invention”) is a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms of 45 to 80. 100% by weight of polyethylene resin having the following characteristics (1) to (2), including 20% to 55% by weight and 20 to 55% by weight of high-pressure radical method polyethylene resin (1) at 190 ° C. under a load of 21.18N Measured melt flow rate (MFR) is 0.5 to 4.0 g / 10 min (2) Density is 0.905 to 0.935 g / cm ³
And 0.8 to 4.0 parts by weight of an alkoxyimino group-type hindered amine compound.

  Hereinafter, the present invention will be described for each item.

(1) MFR
MFR (190 degreeC, 21.18N load) of the polyethylene-type resin used for this invention is 0.5-4.0 g / 10min, Preferably it is 0.7-3.5 g / 10min, More preferably, it is 1 0.0 to 3.0 g / 10 min. If the MFR exceeds 4.0 g / 10 min, the molten resin tends to sag when ignited by a flame, the flameproof performance deteriorates, and the film strength is inferior. Produce. If the MFR is smaller than 0.5 g / 10 min, the load on the extruder during molding and extrusion increases, resulting in an increase in processing costs such as electricity charges, and a thin film of about 30 to 35 μm due to insufficient melt ductility of the resin. Interferes with the production of
In addition, MFR is the value measured based on JIS-K6922-2: 1997 appendix (190 degreeC, 21.18N load).

(2) Density The density of the polyethylene resin used in the present invention is 0.905 to 0.935 g / cm ³ , preferably 0.910 to 0.930 g / cm ³ , and more preferably 0.918 to 0.03. 928 g / cm ³ . When the density is less than 0.905 g / cm ³ , the film handling properties are significantly lowered, such as insufficient film rigidity, wrinkling during on-site construction of the film, and close contact of the film stack. On the other hand, when the density is greater than 0.935 g / cm ^3, the transparency of the film is deteriorated, and the impact strength is lowered as well as the visibility of the construction site and the daylighting are lowered.
The density is a value measured according to JIS K-7112.

(3) Polyethylene resin The polyethylene resin used in the present invention comprises 45 to 80% by weight of a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms, and 20 to 55% by weight of a high-pressure radical polyethylene resin. It is preferable that it is a polyethylene-type resin containing. Among copolymers of ethylene and an α-olefin having 3 to 12 carbon atoms, a copolymer of ethylene and an α-olefin having 3 to 10 carbon atoms is more preferable.

  Specific examples of the α-olefin used as a comonomer of a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms include propylene, butene-1,4-methylpentene-1, hexene-1, octene- 1, decene-1, dodecene-1, and the like. Moreover, it is preferable that content of (alpha) -olefin is 3-40 mol% with respect to 100 mol% of all the monomers of the said copolymer. A copolymer having a long chain branch may be used as the copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms.

The polymerization catalyst used for the production of a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms is not particularly limited, and is conventionally known as a Ziegler catalyst, a vanadium catalyst, a Philips catalyst, a metallocene catalyst, or the like. Can be used. Of these, single-site catalysts such as metallocene catalysts are preferred.
The single-site catalyst is not particularly limited, and a conventionally known catalyst can be used, but preferably a catalyst comprising a metallocene compound such as a zirconium compound coordinated with a group having a cyclopentadienyl skeleton and the like and a promoter. Examples of the catalyst include components. Use of a copolymer of ethylene and α-olefin polymerized with these single site catalysts is preferable because of excellent mechanical strength of the film.

  Examples of the method for producing a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms include a high-pressure ion polymerization method, a gas phase method, a solution method, a slurry method, and the like. It doesn't matter.

  A copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms can be appropriately selected from commercially available products. As a commercial item, brand name Novatec LL (registered trademark) “UF230” (manufactured by Nippon Polyethylene Co., Ltd.), brand name: Harmolex (registered trademark) “NF366A” (manufactured by Nippon Polyethylene Co., Ltd.) and the like can be mentioned.

  On the other hand, the high-pressure radical polyethylene resin refers to low-density polyethylene obtained by a high-pressure radical polymerization method. The high-pressure polyethylene resin used in the present invention can be appropriately selected from commercially available products. As a commercial item, a brand name: Novatec LD (registered trademark) “ZF33” (manufactured by Nippon Polyethylene Co., Ltd.), a brand name: Novatec LD (registered trademark) “LF240” (manufactured by Nippon Polyethylene Co., Ltd.) and the like can be mentioned.

  The blending ratio of the polyethylene resin is 45 to 80% by weight of a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms, and 20 to 55% by weight of a high-pressure radical polyethylene resin. When the copolymer of ethylene and α-olefin exceeds 80% by weight, or when the high-pressure radical polyethylene resin is less than 20% by weight, the resin is largely melted at the time of ignition by a flame, and the intended flameproofing Performance cannot be obtained. Moreover, the film formation stability at the time of forming an inflation film also deteriorates, and it becomes difficult to obtain a good film without wrinkles. Moreover, when the blending ratio of the copolymer of ethylene and α-olefin is less than 45% by weight, or when the blending ratio of the high-pressure radical polyethylene resin exceeds 55% by weight, the strength of the film decreases, The desired strength as a curing film cannot be obtained.

(4) Alkoxyimino group type hindered amine compound As the alkoxyimino group type hindered amine compound used in the present invention, for example, a group represented by the general formula (1) described in JP-T-2002-507238 is used. A hindered amine-based compound or a reaction product thereof can be used.

(In the formula, G ¹ and G ² each independently represent an alkyl group having 1 to 4 carbon atoms or together represent a pentamethylene group, Z ¹ and Z ² each have a methyl group, and To form a ring structure, which may be substituted by an ester group, an ether group, an amide group, an amino group, a carboxyl group, or a urethane group. 18 represents an alkoxy group having 18 carbon atoms, a cycloalkoxy group having 5 to 12 carbon atoms, an aralkyloxy group having 7 to 25 carbon atoms, and an aryloxy group having 6 to 12 carbon atoms.)

In the general formula (1), Z ¹ and Z ² are bonded to each other to form a 6-membered ring, particularly a substituted piperidine ring, specifically substituted 2,2,6,6- Those having a tetramethylpiperidine structure are preferred. E is preferably a methoxy group, a propoxy group, a cyclohexyloxy group or an octyloxy group, and particularly preferably a propoxy group, a cyclohexyloxy group or an octyloxy group.

  Examples of the hindered amine compound containing the group represented by the general formula (1) or a reaction product thereof include peroxidized 4-butylamino-2,2,6,6-tetramethylpiperidine and 2,4. , 6-Trichloro-S-triazine, cyclohexane and N, N-ethane-1,2-diylbis (1,3-propanediamine), FLAMESTAB NOR 116 (registered trademark, manufactured by BASF Japan) Is commercially available.

  The addition amount of the alkoxyimino group type hindered amine compound used in the present invention is 0.8 to 4.0 parts by weight, preferably 1.0 to 3.0 parts by weight, based on 100 parts by weight of the polyethylene resin. More preferably, it is 1.2 to 2.5 parts by weight. If the addition amount is less than 0.8 part by weight, the performance of JIS flameproofing first grade cannot be obtained. On the other hand, if the addition amount exceeds 4.0 parts by weight, the flameproof performance is saturated and only the cost of the film increases, which is not preferable. The added alkoxyimino group-type hindered amine compound is prepared by granulating and extruding a high-concentration mixture of an alkoxyimino group-type hindered amine compound in the same polyethylene resin as the base resin used in advance. It is preferably melted and kneaded and granulated by a machine and used as a master batch.

(5) Film thickness The thickness of the film of this invention is 25-95 micrometers, Preferably it is 30-90 micrometers, More preferably, it is 40-80 micrometers, More preferably, it is 50-70 micrometers. When the thickness of the film is less than 25 μm, the film strength is insufficient and tearing may occur, and the film cannot be used at the construction site. If the thickness of the film exceeds 95 μm, it will be difficult to achieve JIS flame resistance level 1 even if a predetermined amount of flame retardant is added. This is a problem in terms of economics and the inability to secure the property and the film price increases.

  In the resin composition used for the film of the present invention, various known auxiliary additives generally used for the film, for example, an anti-blocking agent, a slip agent, an antioxidant, a neutralizing agent, a UV absorption, are used as necessary. An agent, a light stabilizer, various pigments and the like can be blended.

  The various auxiliary additives to be added may be prepared by simply blending each desired composition with a Henschel mixer, an extruder, etc., such as dry blending, but are preferably blended beforehand in the base resin at a high concentration. You may use as a master batch melt-kneaded with an extruder. By making a master batch in the form of pellets, handling, transportation and workability are facilitated, and it can be uniformly dispersed in the composition, resulting in no unevenness of addition to the film and obtaining a film with uniform performance. It is done.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In addition, the measurement and evaluation of the physical property in an Example and a comparative example were implemented by the method shown below.

1. Evaluation method of resin physical properties (1) Melt flow rate (MFR): Measured in accordance with JIS-K6922-2: 1997 appendix (190 ° C., 21.18 N load).
(2) Density: Measured according to JIS K-7112.

2. Evaluation Method of Film Properties (1) Haze Using a direct reading haze meter (manufactured by Toyo Seiki Seisakusho), measurement was performed in accordance with JIS-K7361.
(2) Punching impact strength test The penetration fracture energy was measured using a testing machine equipped with the following in accordance with JIS-P8134 (1976).
-A pendulum that has a 90 ° arc-shaped arm that can be attached to the penetrating part at the tip and can vibrate freely.
-The penetrating part is normally made of 25.4mmΦ hemispherical metal, and the surface has a specular gloss and can be securely attached to the tip of the arcuate arm of the pendulum.
-A clamp that clamps the test piece horizontally and uniformly. The standard inner diameter of this clamp is 50 mmΦ.

(3) Flame-proof test The flame-proof test based on JIS-A1322 (1966) was performed, and the flame-proof performance (grade 1-3) was determined.

3. Method for evaluating inflation film molding stability The stability of bubbles (inflation tubes) during inflation film molding was evaluated according to the following criteria.
○: Bubble stability, no molding problems.
Δ: Bubble shaking or film wrinkling.
×: Bubble shaking is large and film molding is impossible

4). Polyethylene resin to be used (1) Ethylene / α-olefin copolymer Ethylene / α-olefin copolymer 1; Novatec LL “UF230” (MFR 1.0 g / 10 min, density 0.921 g / cm ³⁾ manufactured by Nippon Polyethylene , Ziegler catalyst, comonomer; butene 1)
Ethylene / α-olefin copolymer 2: Harmolex “NF366A” manufactured by Nippon Polyethylene Co., Ltd. (MFR 1.5 g / 10 min, density 0.919 g / cm ³ , metallocene catalyst, comonomer; hexene 1)
Ethylene / α-olefin copolymer 3: Kernel “KF380” manufactured by Nippon Polyethylene Co., Ltd. (MFR 4.0 g / 10 min, density 0.918 g / cm ³ , metallocene catalyst, comonomer; hexene 1)
(2) High Pressure Radical Polyethylene-based Resin High Pressure Radical Method PE-1: Novatec LD “ZF33” (MFR 1.1 g / 10 min, density 0.920 g / cm ³ ) manufactured by Nippon Polyethylene
High-pressure radical method PE-2: Novatec LD “LF240” (MFR 0.7 g / 10 min, density 0.924 g / cm ³ ) manufactured by Nippon Polyethylene
High pressure radical method PE-3: Novatec LD “LS640” (MFR 5.0 g / 10 min, density 0.924 g / cm ³ ) manufactured by Nippon Polyethylene

5. Flame retardant to be used Alkoxyimino group type hindered amine compound; FLAMESTAB NOR116 manufactured by BASF Japan Ltd.
Magnesium hydroxide; Kyowa Chemical Industry Kissmer 5A
Antimony trioxide; Nippon Seiko Co., Ltd. Antimony Lister

[Example 1]
1.6 parts by weight of alkoxyimino group-type hindered amine compound is mixed with 100 parts by weight of base resin in which 60% by weight of ethylene / α-olefin copolymer 1 and 40% by weight of high-pressure radical method PE-1 are mixed. Then, using an inflation film molding machine (die diameter: 235 mmφ, lip width: 3 mm), extrusion was performed at a molding temperature of 190 ° C. to obtain a monolayer film having a folded film width of 1,000 mm and a film thickness of 60 μm. In addition, the hindered amine type compound was melt-extruded and kneaded in advance at a high concentration of 20% by weight in the same polyethylene as the base resin, and was added as an MB system. The evaluation results of the obtained film are shown in Table 1.

[Example 2]
Except that the film thickness was 30 μm, molding was performed in the same manner as in Example 1 to obtain a monolayer film having a film folding width of 1,000 mm. The evaluation results of the obtained film are shown in Table 1.

[Example 3]
Except that the film thickness was 90 μm, molding was carried out in the same manner as in Example 1 to obtain a single layer film having a film folding width of 1,000 mm. The evaluation results of the obtained film are shown in Table 1.

[Example 4]
The base resin was molded in the same manner as in Example 1 except that the ethylene / α-olefin copolymer 2 was 60% by weight and the high-pressure radical method PE-2 was 40% by weight. A monolayer film having a thickness of 60 μm was obtained. The evaluation results of the obtained film are shown in Table 1.

[Comparative Example 1]
Molding was performed in the same manner as in Example 1 except that the addition amount of the alkoxyimino group-type hindered amine compound was 0.6 parts by weight, and a single layer film having a film folding width of 1,000 mm and a film thickness of 60 μm was obtained. The evaluation results of the obtained film are shown in Table 1.

[Comparative Example 2]
Except that the film thickness was 100 μm, the film was molded in the same manner as in Example 1 to obtain a single layer film having a film folding width of 1,000 mm. The evaluation results of the obtained film are shown in Table 1.

[Comparative Example 3]
Molding was performed in the same manner as in Example 1 except that the ethylene / α-olefin copolymer 1 was 90% by weight and the high-pressure radical method PE-1 was 10% by weight, and the film folding width was 1,000 mm and the film thickness was 60 μm. A single layer film was obtained. The evaluation results of the obtained film are shown in Table 1.

[Comparative Example 4]
Except that the flame retardant to be added is 30 parts by weight of magnesium hydroxide and 8 parts by weight of antimony trioxide, molding is performed in the same manner as in Example 1 to obtain a single-layer film having a folded film width of 1,000 mm and a film thickness of 60 μm. It was. The mixture of the base resin, magnesium hydroxide, and antimony trioxide was obtained by melting and kneading a predetermined amount with an extrusion kneader in advance. The evaluation results of the obtained film are shown in Table 1.

[Comparative Example 5]
Molding was carried out in the same manner as in Example 1 except that 60% by weight of the ethylene / α-olefin copolymer 3 and 40% by weight of the high-pressure radical method PE-3 were used. I couldn't.

[Evaluation]
From the results shown in Table 1, Examples 1 to 4 satisfying the requirements of the present invention are excellent in flameproof performance, haze, punching impact strength, and molding stability.

  On the other hand, in Comparative Example 1 in which the alkoxyimino group-type hindered amine compound is less than the lower limit specified by the present invention, the flameproof performance is incompatible. Further, in Comparative Example 2 in which the film thickness exceeds the upper limit defined by the present invention, the flameproof performance becomes second grade and the first grade performance cannot be maintained, although a predetermined amount of flame retardant is added. Further, in Comparative Example 3 in which the ethylene / α-olefin copolymer is 90% by weight, the molten resin sagging at the time of ignition is large and the flameproof performance is inferior, and the inflation film molding becomes unstable and bubble shaking occurs. . Further, in Comparative Example 4 using another non-halogen flame retardant different from the present invention, the transparency (haze) is greatly inferior, the strength is reduced, and it is not suitable as a curing film, but also in the stability of inflation molding. There was a problem. Furthermore, in Comparative Example 5 in which the MFR of the ethylene / α-olefin copolymer of the base resin was 4.0 g / 10 min and the MFR of the high pressure radical method PE was 5.0 g / 10 min, the resin was synthesized. The MFR was 4.4 g / 10 min, and the molding stability was significantly impaired, and the film could not be molded.

  The polyethylene-based flame-retardant film of the present invention is suitably used as a curing film for preventing the spread of coating agents and sparks at construction sites with painting, construction sites using fire, painting construction sites under highway piers, etc. It can be useful in industry. Moreover, it can use suitably also as a curing film used at the time of the painting of a motor vehicle.

Claims (3)

It contains 45 to 80% by weight of a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms, and 20 to 55% by weight of a high-pressure radical method polyethylene resin, and has the following characteristics (1) to (2). 100 parts by weight of polyethylene resin (1) MFR (melt flow rate measured at 190 ° C., 21.18 N load) is 0.5 to 4.0 g / 10 minutes (2) Density is 0.905 to 0.935 g / Cm ³
And a film obtained by forming a resin composition containing 0.8 to 4.0 parts by weight of an alkoxyimino group-type hindered amine compound, and having the following characteristics (a) to (d) Polyethylene flame retardant film.
(A) The thickness of the film is 25 to 95 μm
(B) In a flameproof test based on JIS A1322, the flame haze value is 15% or less based on JIS K7106, which is a flameproof grade 1 (d) Puncture impact strength based on JIS P8134 is 0.6 J or more It is.   The polyethylene-based difficult polymer according to claim 1, wherein the copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms is a copolymer polymerized by a single site catalyst such as a metallocene catalyst. Flammable film.   A curing film comprising the flame-retardant film according to claim 1.