JPH07103261B2 - Flame-retardant masterbatch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in ignitability and storage / handling of a masterbatch for flame retardation containing a red phosphorus flame retardant.

(Prior Art) Red phosphorus flame retardant gives high flame retardant effect even if added in a small amount.
It is widely used as a flame retardant for synthetic resins because it has little effect on the physical properties and electrical properties of synthetic resins and has excellent characteristics that other flame retardants do not generate, such as generating no harmful gas during combustion.

In order to improve the affinity between red phosphorus and synthetic resin, the surface of red phosphorus particles is coated with a certain synthetic resin to improve the dispersibility in the base resin, but the kneading temperature is high. For safer and more uniform addition of a thermoplastic resin or the like, a method has been adopted in which a pellet-form masterbatch composed of a red phosphorus flame retardant and a synthetic resin is prepared in advance and kneaded with a flame-retardant resin. Therefore, although the masterbatch contains a high concentration of red phosphorus flame retardant, it has not hitherto been subject to any special legal regulation derived from red phosphorus in handling. However, as a result of the amendment of the Fire Service Act and the ignitability test being imposed on dangerous substances-containing products, conventional red phosphorus-based flame retardant masterbatches based on thermoplastic resins with high flammability are regarded as dangerous substances. It is inevitable to be subject to the regulations of.

Therefore, special management is required for all handling of red phosphorus flame retardant masterbatch, such as manufacturing, transportation, storage, etc., which is a factor that impedes the use of red phosphorus flame retardants as well as new cost burden for business and equipment. Therefore, there is a possibility that its usefulness may not be fully utilized.

(Problems to be Solved by the Invention) The present invention improves the risk of ignition of a masterbatch for flame retardation containing a red phosphorus flame retardant, is safe and convenient to store and handle, and eliminates restrictions on use or It is intended to provide a reduced composition and contribute to a wide range of utilization of red phosphorus flame retardants.

(Means for Solving the Problems) As a result of research on improvement of ignitability and flame retardancy of red phosphorus-based pellet-type masterbatch for flame retardation, the inventors have found that the surface of the pellet is dispersed by using a dispersant and a powdered inorganic substance. By forming a coating layer of a powdered inorganic substance on the above, it was discovered that the ignitability and flame retardancy were remarkably reduced, and no restrictions were imposed on handling or restrictions could be relaxed, and the present invention was reached.

That is, the present invention is characterized in that a dispersant and a powdered inorganic substance are used in a pelletized masterbatch containing a red phosphorus flame retardant and a synthetic resin to form a coating layer of the powdered inorganic substance on the surface of the pellet. The present invention relates to a flame retardant masterbatch having improved ignitability. The red phosphorus-based pellet-type masterbatch for flame retardation usually contains several tens of percent of the red phosphorus-based flame retardant, and pellets of highly flammable resin are all classified as dangerous substances under the Fire Defense Law. Although it is not possible to improve the ignitability at all by simply mixing these with a powdered inorganic substance, it is possible to improve the ignitability by treating either the resin pellets or the powdered inorganic substance with a dispersant of a certain type in advance. Similarly, the powdered inorganic substance adheres to form an ignition-inhibiting coating layer. The adhesion of the powdered inorganic substance is stronger than expected, and it is hardly peeled off into powder or dust during normal handling work, so the coating layer is extremely stable and excellent in improving ignitability. Be effective.
The synthetic resin constituting the flame-retardant masterbatch of the present invention, polyethylene, polyolefin resin such as polypropylene, PET, polyester resin such as PBT, polyamide resin, polystyrene resin, AS, ABS, PPO, modified PPO, polychlorinated Examples include vinyl resin.

As the powdery inorganic material used in the present invention, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, basic magnesium carbonate, hydrotalcite, pyrophyllite, sericite, attapulgite, dawsonite, borax, zinc borate, calcium sulfate. Examples of such substances that exhibit endothermic properties when heated, such as titanium dioxide, ammonium polyphosphate, and carbon powder, are used alone or as a mixture.

Many of these powdery inorganic substances have already been used as synthetic resin additives, and in carrying out the present invention, if a powdery inorganic substance of the same kind as the additive of the flame-retardant resin is used, the effect on the synthetic resin will be reduced. Can be almost ignored.

As the dispersant, in principle, any substance can be used as long as it can effectively disperse the powdered inorganic substance on the surface of the resin pellet to form the coating layer, but the influence on the physical properties of the synthetic resin is not affected. Taking into consideration, lubricants, antistatic agents, dispersants, which are usually used as additives for synthetic resins,
Surfactants, antioxidants, plasticizers, spreading agents and the like are particularly preferable as those exhibiting an effective dispersing action. It is more convenient to use dispersants of the same type as the additives used in order to avoid affecting the physical properties of the synthetic resin.

Therefore, the dispersant of the present invention is a general term for substances capable of forming a stable coating layer by dispersing and adhering powdery inorganic compounds on the surface of resin pellets.

The content of the red phosphorus flame retardant in the masterbatch for flame retardation of the present invention can be arbitrarily adjusted depending on the composition of the raw material resin pellets and the amount of the powdered inorganic substance attached. The concentration of flame retardant in a red phosphorus pellet-shaped masterbatch for flame retardation is usually 20-40.
Although the weight percentage is practical, according to the present invention, it is possible to provide a flame retardant masterbatch having improved ignitability even in a resin pellet having extremely large ignitability in almost the entire practical concentration range, With resin pellets having a relatively low ignitability, the effect extends to a region of higher concentration. The raw material resin pellets are generally a two-component mixture of a synthetic resin and a red phosphorus flame retardant, but in the present invention, a filler and other additives may be included. In particular, a three-component blend containing a filler is effective as a method for obtaining a composition having a high flame retardant concentration. The amount of the powdered inorganic substance attached varies depending on the composition of the raw material resin pellets and the content of the desired flame retardant, but is usually 1 to 30 parts by weight per 100 weight parts of the raw material resin pellets, which is practical and preferable. If it is less than 1 part, the effect is not sufficient, and if it exceeds 30 parts, the effect is not changed.

The amount of the dispersant used is usually 0.1 to 1 part by weight per 100 parts by weight of the raw material resin pellets. The dispersant may be powdery or liquid, and the powdery one is thoroughly mixed with the powdery inorganic substance and then mixed with the raw material resin pellets, and the liquid one is spread on the raw material resin pellets and then mixed with the powdery inorganic substance. It is convenient to use them as a mixture. Further, particles of powdered inorganic material which have been surface-treated with a dispersant in advance can also be used.

In order to carry out the present invention, a raw material resin composition is pelletized by an ordinary extruder and a coating process is performed with a dispersant or a powdered inorganic substance by using a mixer such as a tumbler without using a special apparatus.

(Function) In the present invention, the dispersant uniformly and firmly adheres the powdered inorganic substance to the surface of the raw material resin composition to form a coating layer, and the coating layer has an action of delaying or suppressing ignition. .

(Examples) Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

Examples 1 to 8 Polystyrene resin (Styron manufactured by Asahi Kasei Kogyo Co., Ltd.) and red phosphorus flame retardant (Novared 120 manufactured by Rin Kagaku Kogyo Co., Ltd.) were mixed at a predetermined mixing ratio and pelletized by a single-screw extruder to prepare raw materials. Pellets were prepared.

After mixing 100 g of the raw material pellets with 0.5 g of a dispersant (POLYSTAR manufactured by NOF CORPORATION), powdered inorganic substances were mixed and adhered to perform coating treatment. Samples with different flame retardant concentrations were prepared by varying the amount of powdered inorganics. The composition of the raw material pellets and the type of powdery inorganic material used as the treating agent are shown in Table 1, and the results of the ignitability test of each sample are shown in Table 2.

Comparative Example 1 Pellets having different flame retardant concentrations were prepared in the same manner as the raw material pellets of Examples 1 to 8, and an ignitability test was conducted using the pellets as comparative samples.

Examples 9 to 10 Raw material pellets consisting of three components of polystyrene resin, red phosphorus flame retardant and magnesium hydroxide were prepared in accordance with Examples 1 to 8, and the pellets were coated with a powdered inorganic material and an ignitability test was conducted. It was However, 0.5 g of calcium stearate (Tannan Chemical Co., Ltd.) was used as a dispersant. The composition of the raw material pellets and the type of powdered inorganic material are shown in Table 1, and the results of the ignitability test are shown in Table 2.

Examples 11 to 13 Polyethylene resin (manufactured by Nippon Unicar Co., Ltd.) and red phosphorus flame retardant were mixed in a predetermined ratio, and raw material pellets and comparative pellets were prepared according to Examples 1 to 8. The raw material pellets are coated with a powdered inorganic material in the same manner as in the previous example,
An ignitability test was performed and compared with a comparative pellet. The results of the comparative pellets are shown as Comparative Example 2. The composition of the raw material pellets and the type of powdered inorganic material are shown in Table 3, and the results of the ignitability test are shown in Table 4.

Test method Place a sample of 3 cm ³ on a hard rock wool (120 mm x 120 mm x 12 mm Nichias Co., Ltd.) in a hemispherical shape, and a liquefied petroleum gas flame (flame length becomes 70 mm with the flame mouth facing up) (Using an ignition device adjusted in this way) for 10 seconds to measure the time until ignition and the duration of combustion after ignition. Repeat this 10 times for the same sample.

Judgment method The result of the ignitability test is judged according to the following three stages.

(1) Once ignited within 3 seconds and burned all within 10 seconds or after releasing the flame, continue burning for 10 seconds or more or burn all within 10 seconds (dangerous goods under the Fire Service Act) (Corresponds to Class 2 Class 1 combustible solids) (2) One that ignites within 10 seconds at a time and continues combustion for 10 seconds or longer (corresponds to Class 2 Class 2 combustible solids of the Hazardous Materials of the Fire Service Act) (3) Those that do not ignite or that do not continue combustion for more than 10 seconds after releasing the flame even if ignited within 10 seconds (not applicable to the dangerous goods under the Fire Service Act), mark 1 in the table, mark 2 ) For △, Judgment 3) for ○
It is indicated by a mark.

(Effects) As shown in the table, all the comparative pellets corresponding to the conventional masterbatch composition for flame retardation are dangerous substances, but were coated with a powdered inorganic substance using a dispersant according to the present invention. The ignitability of the product is significantly reduced and it is no longer a hazardous material, or it is a Class 2 product with improved ignitability. By adjusting the composition of the raw material pellets, it is possible to obtain those that do not correspond to dangerous substances in any practical concentration range. Whether the masterbatch for flame retardant is designated as a dangerous substance, whether it is the first type or the second type is very important for the related industry because there is a large difference in handling regulations. It's a problem. INDUSTRIAL APPLICABILITY The present invention can provide a red phosphorus-based flame retardant masterbatch that does not correspond to a dangerous substance at all or is loosely regulated, and the safety effect as well as the storage handling is extremely remarkable, which is an excellent difficulty. It can contribute to widespread use of red phosphorus flame retardants, which are flame retardants.

Further, in implementing the present invention, no special device is required,
It can be easily performed with a simple mixing device that is usually used, and the dispersant and powdered inorganic substances used are already used as additives for synthetic resins, and the effect on the properties of synthetic resins is extremely small. This is an advantage of the present invention.

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Claims (1)

[Claims] 1. A pellet-shaped masterbatch containing a red phosphorus flame retardant and a synthetic resin, wherein a dispersant and a powdered inorganic substance are used to form a coating layer of the powdered inorganic substance on the surface of the pellet. Masterbatch for flame retardant with improved ignitability.