JP2013124340A - Flame-retardant synthetic resin film amd method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flame-retardant synthetic resin film easily molded, having moderate flexibility and passing UL-94VTM-O standard.SOLUTION: A polypropylene resin is sufficiently plasticized even at a temperature lower than the molding temperature of a homopolypropylene by mixing 50-0 mass% random polypropylene having lower melting point and more flexible than the homopolypropylene, with 50-100 mass% homopolypropylene having excellent rigidity and heat resistance and high melting point as polypropylene resin; and the film formed to have 0.1-0.3 mm thickness is not made hard even if piperazine pyrophosphate or melamine cyanurate is mixed. The film having improved flame retardancy is obtained while keeping mechanical strength by mixing 40-80 pts.mass piperazine pyrophosphate and 30-60 pts.mass melamine cyanurate with 100 pts.mass polypropylene resin.

Description

  The present invention relates to a flame retardant synthetic resin film and a method for producing the flame retardant synthetic resin film.

  The flame retardant resin composition described in the following Patent Document 1 includes 10 to 70 parts by mass of piperazine pyrophosphate, 70 parts by mass of melamine cyanurate 1 with respect to 70 parts by mass of a polypropylene resin (manufactured by Prime Polymer: J-750HP injection molding grade). -30 mass parts, 0.01-1 mass part of anti-drip agent, and 0.1-4 mass parts of metal oxide are mix | blended. This flame retardant resin composition is tested with a test piece having a thickness of 1.6 mm based on UL-94 (vertical combustion test method) of UL standards as a flame retardant test. The flame retardance which passes V-0 which is evaluation is shown (for example, refer patent document 1).

JP 2011-148936 A

Such a conventional flame retardant resin composition passes the UL94 vertical burning test (V-0) standard using a 1.6 mm thick test piece, but is formed into a thin film. Good flame retardancy cannot be obtained. For example, when the UL94V-0 test is performed with a thin film-shaped test piece of about 0.1 to 0.3 mm, one of the criteria is “whether the cotton is ignited by flame particles or flame drops (droplets). "Cotton ignition by") fails.
For this reason, it has been difficult to pass the UL-94 Thin Material Vertical Burning Test (VTM-0) standard corresponding to a thin film.
By the way, when forming into a thin film of about 0.1 to 0.3 mm using homopolypropylene which is a homopolymer of polypropylene, the homopolypropylene is crystalline and has a melting point (160 to 170 ° C., equilibrium melting point is 185). (˜190 ° C.) was high and had to be processed at a high temperature.
And homopolypropylene has a problem that it becomes too hard when a large amount of flame retardant is blended.
Furthermore, when the polypropylene flame retardant resin composition is formed into a thin film having a thickness of about 0.1 to 0.3 mm by an ordinary extrusion molding, the surface of the film is not smooth and has no commercial properties. This phenomenon is presumed to be due to aggregation of piperazine pyrophosphate and decomposition of melamine cyanurate. This phenomenon is considered to occur because the processing temperature (220 to 230 ° C.) of the polypropylene film is too high. This phenomenon is considered to be unavoidable when the molding temperature is high.
In addition, the calendar molding usually performed as a film molding method tends to be insufficiently dispersed even if the flame retardant is made into a master batch. The polypropylene flame retardant resin composition has a problem that the surface of the film is not smooth and has no commercial properties in a calendar line that does not use Banbury. Even in calendar molding at a normal Banbury temperature (150 to 160 ° C.), there is a problem that the smoothness is insufficient.

  An object of the present invention is to provide a flame retardant synthetic resin film that is easy to mold, has an appropriate flexibility, and passes the UL-94 VTM-0 standard. , And so on.

  In order to achieve such an object, the flame retardant synthetic resin film according to the present invention comprises piperazine pyrophosphate with respect to 100 parts by mass of polypropylene resin composed of 50 to 100% by mass of homopolypropylene and 50 to 0% by mass of random polypropylene. It contains 40 to 80 parts by mass and melamine cyanurate 30 to 60 parts by mass, and is formed into a film having a thickness of 0.1 to 0.3 mm.

The flame-retardant synthetic resin film according to the present invention having the above-described characteristics is a flexible polypropylene resin having a melting point lower than that of homopolypropylene as compared to 50 to 100% by mass of homopolypropylene having excellent rigidity and heat resistance and a high melting point. By blending 50 to 0% by mass of random polypropylene, the polypropylene resin is sufficiently plasticized even at a molding temperature lower than the molding temperature of homopolypropylene, and a film molded to a thickness of 0.1 to 0.3 mm It itself does not become hard even when it is mixed with piperazine pyrophosphate or melamine cyanurate. Furthermore, 40 to 80 parts by mass of piperazine pyrophosphate and 30 to 60 parts by mass of melamine cyanurate are added to 100 parts by mass of polypropylene resin. By doing so, flame retardancy is maintained while maintaining the mechanical properties of the film itself. Since the upper, it is possible to provide a flame-retardant synthetic resin film molding pass the easy having appropriate flexibility and UL-94VTM-0 standard.
As a result, a film having a thickness of 0.1 to 0.3 mm can be formed even if the molding temperature is lower than that of the extrusion molding method, and the film itself does not need to be formed at a high temperature. Can also be prevented from browning. Furthermore, since inexpensive and flexible random polypropylene is industrially easily available and inexpensive, it is economical because the cost can be reduced.
Further, it can be used in, for example, electric / electronic devices that require the UL-94 standard to pass as a flame retardant standard.

Hereinafter, embodiments of the present invention will be described in detail.
The flame-retardant synthetic resin film according to the embodiment of the present invention contains piperazine pyrophosphate and melamine cyanurate with respect to a polypropylene resin composed of homopolypropylene and random polypropylene, and has a thickness of 0.1 to 0.3 mm. It is configured by forming into a film.

As an example of blending homopolypropylene, which is a homopolymer of polypropylene, and random polypropylene, which is a random copolymer, even if a flame retardant such as piperazine pyrophosphate or melamine cyanurate is blended, the film itself can have an appropriate flexibility. Homopolypropylene is 50 to 100% by mass, and random polypropylene is 50 to 0% by mass.
Furthermore, in order to increase flexibility, it is preferable that the blending ratio of both is 50 to 75% by mass of homopolypropylene and 50 to 25% by mass of random polypropylene.

As the piperazine pyrophosphate, piperazine pyrophosphate described in, for example, JP-A-48-087991 and US Pat. No. 4,599,375 is used.
When the amount of piperazine pyrophosphate is reduced, the flame retardancy of the obtained flame retardant synthetic resin film is lowered, and when it is increased, the mechanical properties of the obtained flame retardant synthetic resin film are lowered. It is 40-80 mass parts with respect to a part, Preferably it is 45-55 mass parts.

Melamine cyanurate is a powdered product of the reaction product of melamine and cyanuric acid. It has a large amount of nitrogen atoms in its structure and generates nitrogen gas when exposed to high temperatures of about 350 ° C or higher. It works to inhibit combustion. Although cyanuric acid has two tautomers, an enol type and a keto type, cyanuric acid as used in the present invention means both an enol type and a keto type.
When the amount of melamine cyanurate is decreased, the flame retardancy of the obtained flame retardant synthetic resin film is lowered, and when it is increased, the mechanical properties of the obtained flame retardant synthetic resin film are lowered. 30 to 60 parts by mass, preferably 31 to 35 parts by mass with respect to parts.

Furthermore, in the flame-retardant synthetic resin film according to the present invention, it is preferable to blend a known general anti-drip agent in order to prevent resin dripping (drip) during combustion.
Specific examples of the anti-drip agent include, for example, fluorine resins such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride, polyhexafluoropropylene, sodium perfluoromethanesulfonate, and potassium perfluoro-n-butanesulfonate. Perfluoroalkanesulfonic acid alkali metal salts such as perfluoro-t-butanesulfonic acid potassium salt, perfluorooctanesulfonic acid sodium salt, perfluoro-2-ethylhexanesulfonic acid calcium salt, or perfluoroalkanesulfonic acid alkaline earth Metal salts and silicone rubbers can be mentioned, and these can be used alone or in combination of two or more. Among these, PTFE is particularly preferably used since it has an excellent drip prevention effect.
When the amount of PTFE is decreased, the drip prevention effect of the flame-retardant synthetic resin film is small, and when it is increased, the cost of the flame-retardant synthetic resin film is increased. 10 parts by mass, preferably 1 to 5 parts by mass.

Furthermore, in the flame-retardant synthetic resin film according to the present invention, it is preferable to blend a metal oxide as an essential component in order to further improve flame retardancy. Specific examples of the metal oxide include titanium oxide, zinc oxide, magnesium oxide, strontium oxide, and the like, and these can be used alone or in combination of two or more. Among these, titanium oxide is particularly suitable because it is excellent in flame retardancy and heat resistance.
When the amount of titanium oxide added decreases, the flame retardancy of the resulting flame retardant synthetic resin film decreases, and when it increases, the flame retardant of the obtained flame retardant synthetic resin film increases, but the kneaded product foams during production. And since discharge and resin pressure may become unstable, it is 0.1-2 mass parts with respect to 100 mass parts of polypropylene resin, Preferably it is 0.5-1 mass part.

Moreover, it is preferable to mix | blend a fatty-acid metal salt (metal soap) as a lubricant at the time of shape | molding the flame-retardant synthetic resin film which concerns on this invention into a film form, for example by calender molding.
The addition amount of the fatty acid metal salt is 0.05 to 1 part by mass, preferably 0.1 to 0.5 part by mass with respect to 100 parts by mass of the polypropylene resin.
Furthermore, if necessary, it may be stabilized with magnesium hydroxide, phenolic antioxidant, phosphorus antioxidant, thioether antioxidant, ultraviolet absorber, hindered amine light stabilizer, etc., or p-tert-butylbenzoic acid. Add nucleating agents such as aluminum, aromatic phosphate metal salts, dibenzylidene sorbitols, antistatic agents, hydrotalcite, triazine ring-containing compounds, fillers, pigments, lubricants, foaming agents, etc. Is also possible.

And the manufacturing method for producing the flame-retardant synthetic resin film according to the embodiment of the present invention includes, for example, calendar molding, extrusion molding, etc. as a method of forming a film having a thickness of 0.1 to 0.3 mm. Used.
Specific examples of calendar molding include a mixing (compounding) process comprising a ribbon blender, a kneading process comprising a Banbury mixer and a mixing roll, a filtration separating process comprising a strainer, a rolling process comprising a calendar roll, and the like. It has a cooling process including a cooling roll and a winding process including a winder.
In particular, after kneading the composition with a Banbury mixer as the kneading step, it is preferable to roll the film into a film of 0.1 to 0.3 mm with a calender roll as the rolling step.
As another example, it is possible to perform extrusion molding using an extruder or molding using another existing molding machine instead of calendar molding.

Examples 1-4 and Comparative Examples 1-9
The components shown in Table 1 were mixed at respective ratios, and a film having a thickness of 0.1 mm was obtained by calendering. Specifically, each component was mixed with a ribbon blender, kneaded with a Banbury mixer (resin temperature at discharge 170 to 180 ° C.) and a mixing roll, and then rolled with a calender roll (set temperature 175 to 185 ° C.) through a strainer.
In Table 1, “homopolypropylene” is Nobrene FHX20E1 manufactured by Sumitomo Chemical. “Random polypropylene” is Nobrene FS-3611 manufactured by Sumitomo Chemical. "Piperazine pyrophosphate", "melamine cyanurate", "PTFE", and "titanium oxide" use a phosphorous nitrogen-based flame retardant (SCRF-5N) manufactured by Sakai Chemical Co., Ltd. as a shortage of "melamine cyanurate". MC-4000 made from was used. “Magnesium hydroxide” is Kisuma 5J manufactured by Kyowa Chemical.
A plurality of test pieces having a length of 200 mm and a width of 50 mm were prepared from the obtained film having a thickness of 0.1 mm, and a UL-94 Thin Material Vertical Burning Test (VTM) -0 test was performed. It was.
Furthermore, the processability of calendar molding was also evaluated.
For Examples 1 to 3 and Comparative Examples 1 and 2, the texture (hardness) of each film was evaluated based on Example 1, and the Young's modulus (Mpa) was used to quantify each hardness. Calculated.
The results are also shown in Table 1. In Table 1, blanks in the evaluation items are not measured.

The test method of UL-94VTM-0 and its judgment criteria are as follows.
Each film test piece is wound around a mandrel having a diameter of 13 mm and attached vertically to a clamp, and a 3-second indirect flame with a 20 mm flame is performed twice, and pass / fail is determined by its combustion behavior.
Judgment criteria are that the burning time of each film specimen is 10 seconds or less, that the total burning time of 5 films is 50 seconds or less, the burning + glowing time of each film specimen is 30 seconds or less, It is necessary to satisfy all that there is no combustion up to the clamp and that there is no ignition of the lower cotton (cotton ignition by dripping) due to the fire type falling from each film specimen.

As can be seen from Table 1, Examples 1 to 4 in which the proportion of the polypropylene resin and the blending amount of the flame retardant are within the scope of the present invention passed the UL-94 VTM-0 standard.
As for the hardness of each film in Examples 1-3, each Young's modulus is settled in 2000-3200 MPa. In particular, Examples 1 and 2 have Young's modulus within 2000 to 2500 MPa. The texture (hardness) of each film in Examples 1 to 4 also had appropriate flexibility.
Furthermore, there was no problem with the workability of calendar molding.

On the other hand, in Comparative Examples 1 and 2, since the blending amount of homopolypropylene was insufficient, there was cotton ignition due to the dropped material and the UL-94VTM-0 standard was rejected.
Since Comparative Examples 3 and 4 are insufficient in the amount of piperazine pyrophosphate, Comparative Examples 3 and 5-7 are insufficient in the amount of melamine cyanurate. It was longer than 10 seconds and was ignited with cotton by droppings, so it failed the UL-94 VTM-0 standard.
In Comparative Example 8, since the blending amount of melamine cyanurate was large, the burning time of each film test piece was longer than 10 seconds and failed the UL-94 VTM-0 standard.
Comparative Example 9 is a case where magnesium hydroxide was blended instead of piperazine pyrophosphate and melamine cyanurate, and the burning time of each film test piece was longer than 10 seconds and failed the UL-94 VTM-0 standard. In addition, with regard to the workability of calender molding, a plate-out (a phenomenon in which a part of the blended components adheres to the processing machine surface during processing) occurred, and there was a problem in releasability from the roll.

  And, when the blending ratio of the polypropylene resin is 50 to 75% by mass of homopolypropylene and 50 to 25% by mass of random polypropylene as in Example 2 of the present invention, the calendar molding method may be used. A film having a thickness of 0.1 mm excellent in flexibility could be reliably formed without causing any trouble.

Furthermore, as in Examples 1 to 4, when calendering was performed to form a film with a thickness of 0.1 mm, the piperazine pyrophosphate agglomerates disappeared and no grains were formed.
Thereby, it is possible to prevent abnormal appearance and decrease in strength due to aggregation of piperazine pyrophosphate.

Furthermore, when a fatty acid metal salt (metal soap) is contained as a calendering lubricant, the melamine cyanurate has an effect of improving slipping, and therefore, calendering can be performed only with the fatty acid metal salt.
Thereby, film formation can be performed with a small amount of lubricant.

Moreover, as a manufacturing method of the flame-retardant synthetic resin film according to the present invention, when the blended components were kneaded with a Banbury mixer and then rolled with a calendar roll, the dispersibility of the blended components was increased.
Thereby, the abnormality of the external appearance and the fall of intensity | strength by aggregation of a mixing | blending component can be prevented reliably.

Claims (5)

  It contains 40-80 parts by mass of piperazine pyrophosphate and 30-60 parts by mass of melamine cyanurate with respect to 100 parts by mass of polypropylene resin consisting of 50-100% by mass of homopolypropylene and 50-0% by mass of random polypropylene. A flame-retardant synthetic resin film formed into a film of 0.1 to 0.3 mm.   2. The flame-retardant synthetic resin film according to claim 1, wherein a blending ratio of the polypropylene resin is 50 to 75 mass% of the homopolypropylene and 50 to 25 mass% of the random polypropylene.   The flame-retardant synthetic resin film according to claim 1 or 2, wherein the molding is calendar molding.   The flame retardant synthetic resin film according to claim 3, wherein the calender molding lubricant contains a fatty acid metal salt.   When producing the flame-retardant synthetic resin film according to claim 3 or 4, the calendering includes a kneading step using a Banbury mixer and a rolling step using a calender roll. Method.