JPH0510380B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a flame-retardant ultra-thin film made of linear high-density polyethylene, and its purpose is to provide an ultra-thin film with extremely high flame retardancy. Currently, in addition to the traditional balance of chemical and physical properties, there is a strong demand for flame safety, that is, flame retardancy, for flammable plastic products, including molded products made of linear high-density polyethylene. ing. This situation is no exception for ultra-thin films, and depending on their flame retardance, they may be withdrawn from some of the previously developed demand fields, such as civil engineering and construction materials, electrical components, and industrial packaging materials. We are in a situation where we may be forced to do so. Although ultra-thin films are sometimes molded using the T-die processing method for special purposes, most of them are usually formed using the inflation processing method. Molding ultra-thin films of linear high-density polyethylene requires processing conditions such as a resin temperature of 190°C to 230°C, a film thickness of 30 microns or less, a large blow ratio, and high-speed productivity of 60 to 100 m/min. The processing conditions are extremely harsh compared to those for other polyolefin products, and the resulting ultra-thin film has no wrinkles or sagging.
Film properties unique to ultra-thin films are required, such as surface smoothness, uniformity of thickness, film strength, and balance in the longitudinal and lateral directions. Naturally, flame retardancy must be achieved while meeting these requirements. Hitherto, hundreds of types of flame retardants and flame retardant methods have been developed and proposed for making plastics flame retardant. However, as mentioned above, it is said that it is extremely difficult to make ultra-thin films made of linear high-density polyethylene flame retardant because strict processing conditions and unique film properties are required. In other words, to make the film flame retardant, it is common to add a flame retardant and, if necessary, a flame retardant aid to the raw material, linear high-density polyethylene, and then process the film. Various problems occur such as foaming due to decomposition of flame retardant, generation of gas corrosive to equipment, inability to form bubbles due to pinholes, instability of bubbles due to uneven thickness, and decreased productivity due to fluctuations in the melt properties of molten resin. do. Furthermore, undesirable phenomena such as wrinkles, sagging, coagulation, gel, and blooming of the flame retardant occur in the obtained film, and at the same time, the required balance of strength is not observed at all. As a result of intensive studies aimed at making ultra-thin films made of linear high-density polyethylene flame-retardant, the present inventors found that among many flame retardants, flame-retardant methods, and flame-retardant compositions, the present invention was found. The inventors discovered the surprising fact that only the composition used as a raw material for the flame-retardant ultra-thin film of the invention makes it possible to manufacture the flame-retardant film, and thus completed the present invention. That is, in the present invention, the melt index is
0.01~0.20g/10min, density 0.945~0.960g/ml
For 100 parts by weight of linear polyethylene, ethylene bis(tetrabromophthalimide) and/or
Or a flame retardant ultra-thin film made by blending 3 to 30 parts by weight of bis(pentabromophenoxy)ethane and 1 to 10 parts by weight of an antimony-based flame retardant aid and/or a boron-based flame retardant aid. It is. The linear polyethylene used in the present invention is
Linear material with basic physical properties of melt index (MI) obtained in accordance with JIS K-7210 of 0.01 to 0.20 g/10 min, and density obtained in accordance with JIS K-7112 of 0.945 to 0.0960 g/ml. This refers to polyethylene manufactured using a medium-low pressure method. Conventional ultra-thin films are
Using the above polyethylene, the following processing conditions are generally used: Resin temperature: 190-230℃ Blow ratio: 3 or more Frost line height: 30-65cm Production speed: 60-100m/min Film thickness: 5-30μm Below, It has a rapid compression metering type screw with an L/D of 24 or more and a compression ratio of 2 to 4,
It is molded by the inflation method using an extruder equipped with a main motor with a capacity of 5.5 to 40 kW, depending on the diameter. The film of the present invention can be applied and molded as is without changing the general manufacturing conditions described above. Ethylene bis(tetrabromophthalimide) and/or bis(pentabromophenoxy)ethane, which are one of the components constituting the ultra-thin film of the present invention, are both marketed as halogen flame retardants.
Currently, it is mainly used to make high-impact polystyrene and ABS resin flame retardant, but it is said that this flame retardant can make it possible to make ultra-thin linear polyethylene films flame retardant in the specific formulation used in the present invention. The facts were completely unknown until now. The amount of the halogen flame retardant necessary to obtain the effects of the present invention is as follows:
The amount is 3 to 30 parts by weight. Preferably it is 5 to 20 parts by weight. If it is less than 3 parts by weight, the flame retardance of the film will be low, and if it is more than 30 parts by weight, it will be difficult to mold the film, making it necessary to change the molding conditions. Examples of antimony-based flame retardant aids used in the present invention include antimony trioxide, potassium antimonate, antimony tetroxide, etc., and examples of boron-based flame retardant aids include zinc borate. be able to. The amount of the flame retardant aid required to obtain the effects of the present invention is 1 to 10 parts by weight per 100 parts by weight of the linear polyethylene. If it is less than 1 part by weight, the effect of addition as a flame retardant aid is small;
If the amount exceeds 10 parts by weight, not only will it not be possible to expect a significant increase in the effect of addition, but it will also be difficult to form the film. The flame retardant ultra-thin film of the present invention has no wrinkles or sagging, its surface is as smooth as a film that does not contain the flame retardant, and no blooming of the flame retardant or flame retardant aid is observed. . moreover,
There are no lumps (coagulates) caused by the flame retardant or flame retardant aid in the film, and the additives are well dispersed. Such film properties meet market requirements and are desirable for effective flame retardancy. Generally, ultra-thin films are often used by subjecting their surfaces to plasma treatment or corona discharge treatment, and then printing or coating them by printing or aluminum vapor deposition. There are no problems with printability or aluminum vapor deposition after surface treatment, and printing or aluminum vapor deposition is possible using conventional methods and operations. As the method for mixing the components of the flame retardant ultra-thin film of the present invention, any known method generally used when adding and blending other organic or inorganic substances to plastics can be used as is. For example, a mixing method using a master batch method can be mentioned.
This is the simplest method, but of course a method of direct mixing may also be used. In addition, it is also a problem that the linear polyethylene for raw materials or the polyethylene for masterbatch production contains commonly added additives, such as antioxidants, ultraviolet absorbers, slip agents, etc., or that they are added as appropriate. do not have. The flame retardant ultra-thin film of the present invention is made by blending a specific flame retardant and flame retardant aid with linear high-density polyethylene. This film was able to overcome the harsh processing conditions and satisfy the physical properties required for conventional ultra-thin films, while also adding flame retardancy. In other words, the flame retardant properties of the present invention can be achieved without any changes to the conventional processing conditions for ultra-thin films and without problems such as decomposition of flame retardants, generation of pinholes, and destabilization of bubbles during processing. Not only can an ultra-thin film be easily produced, but the obtained flame-retardant ultra-thin film of the present invention has no defects such as wrinkles, sagging, coagulation, or blooming, and maintains good film strength and balance. Moreover, it has extremely high flame retardancy. Even if the flame-retardant ultra-thin film of the present invention is ignited, it does not continue to burn and immediately extinguishes the flame.In this respect, safety against flames is ensured, so it can be widely used in fields that require this. can. EXAMPLES The present invention will be explained in more detail below with reference to Examples, but the present invention is not limited to these Examples. Example 1 Pellets of the highly concentrated composition (masterbatch) shown below were produced using a 40 m/m high-speed twin-screw continuous kneader (model NCM manufactured by Kobe Steel, Ltd.) at a resin temperature of 200°C.

[Table] Next, 10 parts by weight of the masterbatch was added to 100 parts by weight of linear polyethylene pellets (Nipolon Hard #7300 manufactured by Toyo Soda Kogyo Co., Ltd., MI = 0.05, density = 0.951), and using a ribbon blender, The pellets were mixed. Using the mixed pellets,
Inflation was performed using an extruder (LM50, manufactured by Plako Co., Ltd.) under the following conditions *Processing conditions: Resin temperature: 200℃ Blow ratio: 6.4 Frost line height: 43cm Production speed: 60m/min Film thickness: 10μm Film molding was carried out by the Chonion method. The obtained film was free of wrinkles and sagging, had a smooth surface, and had no lumps (coagulation) or blooming caused by the flame retardant or flame retardant aid. As shown in Table 1, the film had excellent flame retardancy while maintaining good film strength and balance. Example 2 The same formulation as in Example 1 except that bis(pentabromophenoxy)ethane (manufactured by Ferro Corporation, Pyrocheck 77B) was used instead of ethylene bis(tetrabromophthalimide) in Example 1. Films were produced using the operating procedures and inflation processing conditions. The resulting film had an excellent film appearance similar to the film of Example 1. As shown in Table 1, the film properties such as film strength, film strength balance, and flame retardance were all good. Example 3 The blending amount of the master batch of Example 1 was 10 parts by weight.
A film was produced using the same formulation, operation, procedure, and inflation processing conditions as in Example 1, except that the amount was increased to 20 parts by weight. The bubble stability during manufacturing was good, and the molding process was smooth.
The film appearance, film physical properties, and flame retardance were all very good as shown in Table 1. Example 4 The linear polyethylene pellets used in Example 1 and the halogenated flame retardant and antimony trioxide used in Example 2 were weighed so that the weight composition ratio was 100:20:7, respectively. The polyethylene pellets are melted on a heated roll (manufactured by Nishimura Koki Co., Ltd.) with a roll diameter of 16 inches and a roll temperature of 70±5°C, and then the flame retardant and flame retardant aid are kneaded into the molten polymer.
It was taken out in a mm-thick sheet. The sheet was pelletized using a pelletizer. Using this pellet, film molding was carried out using the same processing machine and the same processing conditions as in Example 1. The stability of the bubble during production was good, and molding was possible without any problems. The appearance of the obtained film was extremely good, as shown in Table 1.
As mentioned above, the film strength, strength balance, flame retardance, etc. were all excellent. Comparative Example 1 The weight composition ratio of the linear polyethylene of Example 4, the halogen-based flame retardant, and the flame retardant aid was 100:
All the same materials as Example 4 except that the ratio was 40:13.
Film forming was carried out using the operations, procedures, and processing conditions. The stability of the bubble during processing was poor, and the molding process did not go well. Comparative Example 2 The same formulation, operation, procedure, and method as in Example 1 were used except that decabromodiphenyl ether (Flame Cut BR100, manufactured by Toyo Soda Kogyo Co., Ltd.) was used instead of the halogenated flame retardant in Example 1. Film molding was performed under the processing conditions. Although moldability was slightly inferior to Examples 1 to 4, film processing was possible. However, blooming of the flame retardant was observed on the surface of the film. Comparative Example 3 A chlorine-based flame retardant (manufactured by Futsuker Chemical Co., Ltd., Dechlorane Plus) was used instead of the halogen-based flame retardant in Example 1.
The film was formed using the same formulation, operation, procedure, and processing conditions as in Example 1, except that 2520) was used. The flame retardance of the obtained film was extremely low. Comparative Example 4 Film molding was carried out under the same formulation, operation, procedure, and processing conditions as in Example 1, except that tetrabromobisphenol A (manufactured by GLC) was used instead of the halogenated flame retardant in Example 1. I went. The flame retardant is commonly used as a flame retardant for ABS resins and epoxy resins. The flame retardant decomposed during molding, making molding impossible.

【table】

[Table] Comparative Example 5 An attempt was made to make an ultra-thin linear polyethylene film flame retardant using chlorinated paraffin, which is often used to make flame retardant films and molded products of low-density polyethylene and ethylene/vinyl acetate copolymers. Ta. Using the kneader of Example 1, a masterbatch pellet having the composition shown below was produced at a resin temperature of 170°C.

【table】

[Table] Films were formed and processed under the same formulation, operation, procedure, and processing conditions as in Example 1. The flame retardant decomposed during molding, making molding completely impossible.

Claims (1)

[Claims] 1. Melt index is 0.01 to 0.20 g/10 minutes,
For 100 parts by weight of linear polyethylene with a density of 0.945 to 0.960 g/ml, (a) ethylene bis(tetrabromophthalimide)
and/or bis(pentabromophenoxy)
A flame retardant ultra-thin product with a thickness of 5 to 30 μm, made by blending 3 to 30 parts by weight of ethane and (b) 1 to 10 parts by weight of an antimony-based flame retardant aid and/or a boron-based flame retardant aid. film.