JPS621414B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to novel polypropylene compositions. Specifically, the present invention relates to a polypropylene composition formed by blending a lubricant and a flame retardant with granular polypropylene. The polypropylene used in the present invention is a general term that includes propylene homopolymers, random copolymers of propylene and other olefins, and block copolymers of propylene and other olefins.
In addition, polypropylene granules are a general term for polypropylene obtained by separating the solvent during propylene polymerization and do not contain 1% by weight or more of particles with particle diameters of 100 μm or less and 1200 μm or more, respectively. Furthermore, in the present invention, "parts" are values expressed in "parts by weight" unless otherwise specified. Conventionally, polypropylene has excellent properties such as chemical resistance, heat resistance, and moldability, so it is used for extrusion molding, injection molding, and other molding of films, sheets, etc., as well as electrical parts, building materials, textile products, It is used in various fields such as hard tools. However, molded products obtained by using polypropylene alone have the disadvantage of being flammable, and their fields of use are limited. In order to improve the above properties, polypropylene compositions containing various organic and inorganic flame retardants singly or in combination are generally used as raw materials for molding. The polypropylene constituting the above polypropylene composition is produced by polymerizing propylene or propylene and other olefins in the presence of a catalyst containing titanium trichloride, so that particles having an average diameter of about 50 to 900 μm are present. A polypropylene powder having a particle size of about 250 μm and an apparent specific gravity of about 0.44 to 0.46 g/ml or less is used. Further, polypropylene granules having a diameter of about 2 to 4 mm and an apparent specific gravity of about 0.50 g/ml obtained by pelletizing the polypropylene powder with a pelletizer may be used. However, when polypropylene powder is directly used as a molding raw material, polypropylene has a disadvantage of poor fluidity because it is a powder with a small apparent specific gravity.
Therefore, when the polypropylene is fed to a molding machine, a shelf hanging phenomenon occurs in the hopper, and stable molding cannot be performed. In addition, since polypropylene powder is a fine particle, there is a risk of powder explosion, and when using a large amount, it is necessary to carry out the process under a nitrogen atmosphere. Furthermore, because of its large surface area, it is susceptible to oxidative decomposition, making long-term storage impossible and requiring transportation in a tank sealed with nitrogen. In order to improve the above-mentioned drawbacks, a method is generally used in which a polypropylene powder composition is once melted and pelletized for stable molding. However, this method has the disadvantage of complicating the process. In addition, when polypropylene granules obtained by pelletizing the above are used as a molding raw material, it is possible to prevent the hanging phenomenon seen when powder is used, but the dispersibility of the flame retardant into polypropylene is poor. , the flame retardancy of the resulting molded product becomes non-uniform.
In addition, flame retardants generally have low thermal stability, and when polypropylene granules are used,
Since there are many opportunities for direct contact with the cylinder and screw, there is a disadvantage that it is easily thermally decomposed. The resulting molded product is colored by the decomposition products, and the radicals generated by the decomposition cause the polypropylene to decompose, resulting in an increase in the melt index. Furthermore, since liquid and low melting point flame retardants become liquid with low viscosity in the feed section of the extruder, they cannot be kneaded when polypropylene granules are used. The present inventors have continued intensive research into solving the above-mentioned problems of polypropylene compositions made by blending flame retardants with polypropylene. By using a lubricant in combination with a lubricant, no shelf hanging phenomenon occurs even when directly molded with a molding machine, there is no risk of dust explosion, and the flame retardant is evenly dispersed without decomposition. The inventors have discovered that it is possible to obtain a product, and have completed the present invention. That is, in the present invention, the lubricant is added in an amount of 0.01 to 100 parts of polypropylene granules having an apparent specific gravity of 0.5 g/ml or more.
This is a polypropylene composition containing 0.6 parts of flame retardant and 0.5 to 200 parts of flame retardant. The apparent specific gravity of the polypropylene granules used in the present invention is 0.5 g/ml or more, preferably 0.52 g/ml.
ml or more. That is, by using polypropylene granules with an apparent specific gravity of 0.5 g/ml, particularly preferably 0.52 g/ml or more, the fluidity of the polypropylene granules is improved for the first time due to the synergistic effect with the lubricant described below. It is possible to prevent the hanging phenomenon when the obtained polypropylene composition is fed from the popper to the molding machine, and to perform stable molding. Another effect of using the polypropylene granules is that the dispersibility of the flame retardant in the polypropylene is significantly improved, and the flame retardance of the resulting molded product is made uniform. Furthermore, due to the interaction with the lubricant described below, the molding temperature is low and the plasticization time is short, so the dispersibility of the flame retardant is also reduced, and there is no decomposition and coloration.
A molded product can be obtained. Moreover, the resulting polypropylene composition has the advantage that the kneading effect during molding is significantly improved and workability is improved. It is preferable to use polypropylene granules with a uniform particle size distribution because this makes the apparent specific gravity of the resulting polypropylene granule composition uniform and further improves the dispersion of the flame retardant. In general, the particle size distribution of polypropylene granules is expressed by the Rosin-Rammler formula, that is, R( _De )=100exp{-( _Dp / _De ) ⁿ } (where _Dp indicates the diameter of the granules. , R(D _p ) is the cumulative weight percent remaining on the sieve, D _e is the particle size characteristic number, and R
(D _p ) = 36.8% by weight, the particle diameter and n are equal numbers), 100≦D _p ≦1200, 0
≦R(D _p )≦100, 100≦D _e ≦800, and n≧2.5, and do not contain 1% by weight or more of particles of 100μ or less and 1% by weight of particles of 1200μ or more, respectively. Preferably used. Said rosin
For information on the particle size distribution expressed by Rammler's equation, see page 338 of "Latest Powder and Granule Processing Technology Collection".
342 pages (edited by the Latest Powder Process Technology Collection Editorial Committee, Industrial Technology Center Co., Ltd., March 1972)
(published on the 15th), it has a sharper particle size distribution than conventional powders.
Furthermore, as described above, the polypropylene granules of the present invention have a particle size distribution represented by the above formula, and
It is most preferable to use extremely sharp polypropylene granules that do not contain more than 1% by weight of particles with a diameter of less than 100 μm and not more than 1% by weight of particles with a size of 1200 μm or more. The method for producing the polypropylene granules having a large apparent specific gravity or having a particle size distribution expressed by the Rosin-Rammler formula is not particularly limited, but is generally an industrially preferred representative method. Examples of manufacturing methods include the following. For example, in the presence of a catalyst containing titanium trichloride and an organoaluminium compound, propylene or propylene and other olefins are polymerized at a polymerization rate of 4 to 70 g/g of polymer/g of titanium trichloride/
within the time range and the amount of polymerization is 3 to 100g/polymer/
g. titanium trichloride, and then polymerizing propylene or propylene and another olefin in the presence of the catalyst-polymer obtained in the prepolymerization.
In particular, in order to effectively obtain polypropylene granules as described above, highly active titanium trichloride, such as titanium trichloride, whose catalytic activity is 2500
This is the case when using TiCl ₃ which is equal to or more than g.polymer/g.TiCl ₃ /hour. These methods for producing TiCl ₃ are not particularly limited, and any method may be used as long as the TiCl ₃ catalytic activity is high as a result when TiCl ₃ polymerizes propylene. A typical example of the manufacturing method for these highly active catalysts is JP-A No. 47-34478.
No., JP-A-49-59094, JP-A-50-126590,
There are Japanese Patent Application Laid-open No. 50-123182, etc. It is particularly preferable to use titanium trichloride having a particle size of 10 to 50 μm and a specific surface area of 80 m ² /g or more. From an industrial standpoint, dialkylaluminum monohalides, particularly diethylaluminum monochloride, are most widely used as the organoaluminum compounds. The catalyst components used to polymerize the propylene or propylene and other olefins need to be the titanium trichloride and the organoaluminium compound, but in addition to these catalyst components, there is also a compound called an electron donor. Addition of a third component can be adopted as necessary. The third component is preferably ethers, nitrogen-containing compounds, phosphorus-containing compounds, esters, etc. as shown in JP-A No. 50-123182, and titanium trichloride and organic aluminum used in advance as necessary. It may be determined by the combination with the compound. In the present invention, the addition of a lubricant has the effect of significantly increasing the apparent specific gravity of the polypropylene granules. The mechanism of how lubricants act on polypropylene granules to dramatically increase their apparent specific gravity is not clear, but it is influenced by the surface properties, particle size distribution, pore conditions, etc. of polypropylene granules. I think that the. The blending ratio of lubricant is 0.01 to 0.6 per 100 parts of polypropylene granules.
part, preferably in the range of 0.02 to 0.3 part. If the amount of the lubricant is less than the above range, the apparent specific gravity of the polypropylene granules cannot be sufficiently increased, and when the resulting polypropylene composition is fed from the hopper to the molding machine, shelving phenomenon tends to occur, and the kneading process becomes difficult. There are disadvantages such as low effectiveness. Furthermore, it is not possible to lower the molding temperature or shorten the plasticization time during molding. On the other hand, if the amount of the lubricant is greater than the above range, the lubricity will be too strong and the resulting polypropylene composition will not only be difficult to knead in the molding machine, but also the apparent specific gravity of the polypropylene granules will be sufficiently large. It cannot be. That is, as for the blending ratio of the lubricant of the present invention, since there is a point within the range of the above blending ratio where the apparent specific gravity of the polypropylene granules is the maximum, the polypropylene granules may be adjusted according to the blending ratio as necessary. It is best to select and use a ratio that increases the apparent specific gravity of . Further, it is preferable that the optimum blending ratio of the lubricant is determined in advance according to the type of polypropylene granules, the type of lubricant, etc. As the lubricant in the present invention, any known lubricant for polypropylene can be used, but the most effective ones are saturated fatty acid metal salts and fatty acid amides.
The former, saturated fatty acid metal salts include stearic acid and other saturated fatty acid metal salts such as calcium,
Metal salts such as zinc, aluminum, cadmium, lead, etc. are preferred. The latter fatty acid amide is preferably a higher fatty acid amide such as stearic acid amide, oleic acid amide, or erucic acid amide. One type of the lubricant may be used, or several types may be used in combination at the same time. However, when using several types of lubricants, polypropylene granules
It is necessary to mix several types of lubricants in a total amount of 0.01 to 0.6 parts per 100 parts. In the present invention, the flame retardant is used in an amount of 0.5 to 200 parts, preferably 1 to 100 parts, per 100 parts of polypropylene granules.
It is preferable to mix 1 part. If the amount of the flame retardant is less than the above range, the flame retardancy of the molded product formed from the resulting polypropylene composition will not be sufficient.
On the other hand, if the amount of the flame retardant is greater than this range, the thermal stability of the resulting polypropylene composition will be reduced, making it more likely to be thermally decomposed, and the fluidity of the polypropylene composition will be significantly reduced. For this reason, for example, even if a shelf suspension prevention device is installed in the hopper of a molding machine, a shelf suspension phenomenon still occurs within the hopper, and kneading in the molding machine becomes difficult. The above flame retardants are generally selected from the above ranges in suitable amounts and blended into polypropylene granules to produce polypropylene compositions for direct molding. It can also be used as a polypropylene composition for masterbatch molding. Conventionally known flame retardants can be used without particular limitation as the flame retardant. For example, organic halides such as decabromo bisphenyl, tetrabromo bisphenol A, and derivatives thereof, tetrabromo butane, dechlorane plus (trade name), chlorinated paraffin, tri(dibromo)propyl phosphate, phosphonium bromide, etc. Organic compounds and inorganic compounds such as antimony trioxide, zirconium oxide, borax, ammonium polyphosphate, ammonium borofluoride, magnesium hydroxide, magnesium carbonate, aluminum hydroxide, titanium oxide, silicon oxide, alkali metal phosphates, etc. They may be used alone or in combination. In the present invention, the lubricant and flame retardant can be blended into the polypropylene granules using a known mixer. For example, a high-speed fluid mixer, a conical screw mixer, etc. are preferably used.
The order of mixing is also not particularly limited, and the polypropylene granules may be premixed with the lubricant and then the flame retardant may be mixed, or the polypropylene granules may be premixed with the flame retardant and then the lubricant may be mixed. Of course, the polypropylene granules, lubricant and flame retardant can also be mixed at the same time. As can be understood from the above explanation, in the polypropylene composition of the present invention, the flame retardant is uniformly dispersed in the polypropylene, so that the flame retardance of the molded product obtained by molding is uniform. It has excellent properties such as being able to prevent the hanging phenomenon in the hopper of the machine, and being able to obtain molded products with good thermal stability due to less decomposition of the flame retardant. Another characteristic is that since the polypropylene constituting the polypropylene composition of the present invention is in the form of granules, it has a higher melting heat capacity than conventional polypropylene compositions that use polypropylene granules made from pelletized powder. It is small, the load on the molding machine is small, and the plasticization time can be significantly shortened. Other additives to the polypropylene composition of the present invention,
For example, heat stabilizers, ultraviolet absorbers, antioxidants, and the like can be added as appropriate. EXAMPLES Examples are shown below to specifically explain the present invention, but the present invention is not limited to these Examples. (1) Melt index (also described as MI) Conforms to ASTMD-1238. (2) Apparent specific gravity Compliant with JISK6721 (1977). (3) Particle size distribution Mesh opening 105, 125, 177, 250, 297, 350,
200g on 420, 500, 590, 710, 1190μ sieve
The sample was loaded into a sieve shaker for 10 minutes and classified. Rosin−, which measured the weight of the residue on the sieve
The particle size specific number D _e and the uniformity number n were determined using a Rammler diagram. The particle size specific number and equivalent number are hereinafter simply expressed as D _e and n. Example 1 (1) Catalyst synthesis After treating brown titanium trichloride obtained by reducing titanium tetrachloride with AlEt ₂ Cl in an inert solvent at room temperature with about an equimolar amount of diisoamyl ether,
The brown titanium trichloride was chemically treated with a 65° C. hexane solution of titanium tetrachloride to obtain titanium trichloride.
The particle size of the titanium trichloride is 20μ and the specific surface area is 132.
m ² /g, and the catalyst activity is 3100g・polymer/
g titanium trichloride/hour. (2) Prepolymerization step 350 ml of heptane was poured into a 1.3 autoclave equipped with a stirrer that had been purged with Tituso gas, and 5.0 g of titanium trichloride described in (1) and 0.8 times the mole of AlEt ₂ Cl relative to titanium trichloride were added. . then
20Nml of hydrogen gas was charged and the temperature was raised to 50°C. Subsequently, propylene gas was supplied at a constant rate so that the polymerization rate was 30 g/g of polymer/titanium trichloride/hour. Polymerization was terminated by purging unreacted gas. The catalyst-polymer slurry thus obtained was used as a catalyst for main polymerization. (3) Main polymerization process 10% of titanium trichloride was added to a 300% stirred autoclave purged with propylene gas.
Add twice the mole of AlEt ₂ Cl and 0.02 times the mole of diethylene glycol dimethyl ether (hereinafter referred to as Diglyme), and then add 200 times the mole of liquid propylene.
and hydrogen gas as a molecular weight regulator, the temperature was raised to 65°C, and then the entire amount of the catalyst-polymer slurry described in (2) was added to initiate main polymerization. During the main polymerization, hydrogen gas was supplied and the gas phase concentration was controlled using gas chromatography to keep it constant. After carrying out the main polymerization for 4 hours, the polymer slurry was discharged from the bottom discharge valve of the autoclave into a flash tank, unreacted propylene was purged to stop the polymerization, and then 200 ml of heptane and 40 ml of methanol were injected. The slurry was made into a slurry and stirred at 60°C for 1 hour to decompose the catalyst. Subsequently, 100 ml of water was injected, the catalyst decomposition product was extracted into the aqueous phase, and the aqueous phase was separated and removed. The heptane slurry of the polymer was separated into solid and liquid using a centrifuge, and the solid was sent to a dryer and dried at 90°C for 6 hours to obtain a granular crystalline polymer. Obtained as described above. The MI value of the polypropylene granules obtained as described above is 8.9, and the apparent specific gravity is 0.53.
(g/ml). The particle size characteristic number D _e indicating the particle size distribution of the granules was 420, and the uniformity number n was 13. Furthermore, particles with a diameter of 100μ or less have a polymerization rate of 0.02% and a diameter of 1200μ.
Particles larger than μ contained 0.1% polymerization. 1.5 kg of the granules were introduced into a high-speed fluid mixer (Super mixer model MSP-5 manufactured by Kawada Seisakusho), and Dechlorane Plus was added as a flame retardant to 100 parts of the granules.
515 (trade name: manufactured by Hooker Chemical Co.), 22 parts of antimony trioxide, and a lubricant as shown in Table 1 were mixed and stirred at a rotational speed of 1500 rpm for 3 minutes. Additionally, 0.1 part of an antioxidant BHT (trade name: manufactured by Yoshitomi Pharmaceutical Co., Ltd.) was added at the same time as a stabilizer. The extrusion amount of the above polypropylene composition was measured using a 90 m/m extruder (full flight type screw with L/D=28 vent) at a resin temperature of 210° C. and a screw rotation speed of 95 rpm. In addition, the presence or absence of hanging on shelves with hoppers and the state of biting with screws were observed. The results are shown in Table 1. A 3φ x 10 strand die was attached to the tip of the extruder, and no wire mesh was attached to the tip of the screw. In addition, the inclination angle of the hopper was 60°.

【table】

[Table] Comparative example Dechlorane plus 45 parts antimony trioxide 22 parts, oleic acid to 100 parts polypropylene powder (manufactured by Tokuyama Soda Co., Ltd.) with M.I8.9 and apparent specific gravity 0.46 g/ml A polypropylene powder composition was obtained in the same manner as in Example 1 using 0.1 part of amide and 0.1 part of BHT using the same mixer. Using the same extruder as in Example 1, the extrusion amount of the obtained powder composition was measured under the same conditions as in Example 1. As a result, the extrusion amount was 95Kg/H
It was hot. In addition, shelf hanging occurs in hoppers,
Moreover, the biting state of the screw was rather poor. Note that the extrusion amount was measured while artificially preventing the occurrence of shelf hanging. Example 2 0.1 part of oleic acid amide was added to 100 parts of polypropylene granules obtained in the same manner as in Example 1.
0.1 part of BHT, Dechlorane Plus and antimony trioxide were blended as shown in Table 2 and mixed in the same manner as in Example 1 to obtain a polypropylene composition. The obtained polypropylene composition was extruded using the same extruder as in Example 1 under the same conditions to obtain pellets. The pellets obtained were observed for their colored bodies and for hanging in the hopper. The results are shown in Table 2.

【table】

[Table] Example 3 To 100 parts of polypropylene granules obtained in the same manner as in Example 1, 0.1 part of oleic acid amide, 45 parts of Dechlorane Plus, 22 parts of antimony trioxide, and 0.1 part of BHT were added. For comparison, a polypropylene composition obtained by mixing and stirring according to the method described in 1. A polypropylene composition prepared by mixing and stirring 45 parts of Dechlorane Plus, 22 parts of antimony trioxide, and 0.1 part of BHT in the same manner as described above was melted under the same conditions using the extruder described in Example 1. Pellets were obtained by extrusion. At this time, changes over time in the screw tip resin pressure were measured. The results are shown in Table 3. Note that three pieces of 60-mesh wire mesh were attached to the tip of the screw, and a 3φ x 10 strand die was used as the die. The screw rotation speed was 95 rpm. Also, put the obtained pellets into the mold respectively.
The mixture was heated and melted at 200° C. for 10 minutes, then press-molded (80 kg/cm ² ) to prepare a combustion test piece measuring 2 mm x 12.7 mm x 127 mm. The test piece was subjected to a vertical combustion test according to the UL94 combustion test method. The results are shown in Table 3.

[Table] Example 4 Using the polypropylene composition described in Example 3, the plasticization time during injection molding was measured. The occurrence of decomposition and coloring was also observed. The injection molding machine used was Ankel V22A (product name: manufactured by Japan Steel Works), and the screw diameter was 55φ and the screw rotation speed was 95 rpm. Also, the cylinder temperature was varied by measuring 150 mm. The result is the fourth
Shown in the table.

【table】

[Table] Example 5 To 100 parts of polypropylene granules obtained in the same manner as in Example 1, 0.2 parts of aluminum stearate was added to 3,5,3',5'-tetrabromo-4,4'-dibromopropoxydiphenyl. Sulfone (product name Nonnene PR-2 manufactured by Marubishi Yuka) and antimony trioxide as shown in Table 5 and the apparent specific gravity for comparison.
A polypropylene composition in which the above flame retardant was blended with a polypropylene powder (manufactured by Tokuyama Soda Co., Ltd.) of 0.45 g/ml and M.I8.9 and a polypropylene granule similar to Example 3 as shown in Table 5. I got something. Example 1 Each of the obtained polypropylene compositions
Pellets were obtained by extrusion using the same extruder as in Example 1 under the same conditions as in Example 1. At this time, the presence or absence of hanging on a shelf in the hopper, biting into the screw, and coloring state of the pellets were observed. The results are shown in Table 5. In addition, the obtained pellets were heated at 200℃.
After heating and melting for 10 minutes, it was press-molded (80Kg/cm ³ ) to create a 2mm x 12.7mm x 127mm test piece.
A vertical combustion test was conducted according to the UL94 combustion test method. The results are also shown in Table 5.

【table】

[Table] Example 6 0.1 part of calcium stearate was added to 100 parts of polypropylene granules obtained in the same manner as in Example 1.
Firemaster LV-T23P (product name:
(manufactured by Hitachi Chemical Co., Ltd.) (liquid), 3 parts of antimony trioxide, and 0.1 part of BHT were mixed in the same manner as in Example 1 to obtain a polypropylene composition. The obtained polypropylene composition was pressed into pellets using the same extruder as in Example 1 under the same conditions. At that time, the state of hanging on the shelf with the hopper and the state of biting into the screw were observed. The results are shown in Table 6. In addition, pellets were prepared in the same manner using the polypropylene granules used in Example 3 and the polypropylene powder used in Example 5 instead of the above granules. At that time, the state of hanging the shelf in the hopper,
And the state of biting into the screw was observed. The results are also shown in Table 6.

【table】

[Table] Example 7 MI value is 10.3, apparent specific gravity is 0.5 g/ml, and D _e is
430, n is 4.5 and particles with a diameter of 100μ or less are 0.05
Polypropylene granules containing 0.1% polymerization of particles with a diameter of 1200μ or more (manufactured by Tokuyama Soda Co., Ltd.)
Calcium stearate 0.1 part per 100 parts, dibromopropyl ether of tetrabisphenol A of the following formula (product name FG3100: manufactured by Teijin Kasei Ltd.) 4.0
Department, And 2.0 parts of antimony trioxide were mixed in the same manner as in Example 1 to obtain a polypropylene composition. Using the obtained polypropylene composition, test pieces were prepared in the same manner as in Example 5, and a combustion test was conducted. As a result, the average self-extinguishing time was 0.1 seconds,
The maximum time was 0.2 seconds and the minimum time was 0 seconds. In addition, there was no shelf hanging in the hopper of the extruder, and the screw biting of the extruder was good. Furthermore, the resin extruded from the extruder was not colored at all.

Claims (1)

[Claims] 1. The apparent specific gravity is 0.50 g/ml or more and the particle size is
1 particle each of 100μ or less and 1200μ or more
Polypropylene granules not containing more than 100% by weight
A polypropylene composition containing 0.01 to 0.6 parts of a lubricant and 0.5 to 200 parts of a flame retardant. 2 Polypropylene granules have the general formula R (Dp) = 100exp {- (Dp / De) ⁿ } (where, Dp indicates the diameter (μ) of the granules,
R (Dp) is the cumulative weight % remaining on the sieve, that is, the weight % of granules larger than Dp, and De is the particle size characteristic number, expressed as the particle diameter when R (Dp) = 36.8 weight %, each 100≦ Dp≦1200, R(Dp)=0~
100, 100≦De≦800, and n≧2.5. 3. The polypropylene composition according to claim 1, wherein the lubricant is at least one selected from the group consisting of metal salts of saturated fatty acids and fatty acid amides.