JPH083362A - Masterbatch of organic peroxide and polypropylene resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject masterbatch, containing an organic peroxide in tale having a specific average particle diameter, excellent in moldability, rigidity and operation safety and capable of producing a crystalline polypropylene-based resin composition having a reduced molecular weight at a reduced production cost. CONSTITUTION:This masterbatch of an organic peroxide is obtained by adding 0.1-50wt.% organic peroxide (e.g. t-butyl peroxybenzoate) to talc having 0.5-30mum average particle diameter and mixing the resultant mixture in a Henschel mixer, etc., for 15 min. Furthermore, this crystalline polypropylene-based resin composition is industrially and advantageously obtained at a reduced production cost with good operation safety by blending 0.1-5 pts.wt. resultant masterbatch with 100 pts.wt. polypropylene, heating and kneading the blend at 180-280 deg.C. The resultant composition is excellent in moldability and rigidity and has a reduced molecular weight.

Description

Detailed Description of the Invention

[0001]

[Industrial field] Master of organic peroxide using talc as a base material, which suppresses the manufacturing cost when manufacturing a crystalline polypropylene resin composition excellent in moldability and rigidity and has good work safety. A batch and a reduced molecular weight polypropylene resin composition obtained using the same.

[0002]

2. Description of the Related Art Polyolefins such as polyethylene and polypropylene are used for various purposes. The physical properties required by these applications are different, and for example polypropylene, which has come to be widely used as an industrial member for automobile parts, is thinned to meet the demand for weight reduction and represented by applications such as instrument panels and door trims. Along with this, higher rigidity is desired, and therefore a polypropylene resin composition having improved fluidity and rigidity is required.

Conventionally, as a method for improving the fluidity of a resin during molding, for example, a method of producing a polymer having a small molecular weight by using a chain transfer agent such as hydrogen at the time of polymerization is known. When a small polymer is produced, the amount of polymer components soluble in the polymerization medium consisting of inert hydrocarbons and monomers such as hexane, heptane, and decane increases, and this polymer tends to adhere to the inner wall of transportation pipes. Since it has, it causes the blockage of the transportation piping. Moreover, since a large amount of hydrogen, which is a chain transfer agent, is introduced into the reaction apparatus, the internal pressure in the reaction apparatus rises, making it difficult to safely and stably produce the polymer.

On the other hand, there is also known a method in which polypropylene and an organic peroxide are heated and melt-kneaded to obtain a low molecular weight product. According to this method, there is no generation of a polymer component which is soluble in the above-mentioned polymerization medium and has poor flow performance in the transport pipe, and it can be carried out easily with an extruder or the like, so that it is relatively easy to use. In that case, since the organic peroxide is a dangerous substance itself, it is generally used as a masterbatch diluted to some extent from the viewpoint of safety in handling. However, in the conventional organic peroxide masterbatch using a resin powder as a base material, the upper limit of the organic peroxide content is limited to about 5%. When the content of the organic peroxide is 5% or more, the organic peroxide is leached from the base material particles, so that the powder property of the obtained masterbatch becomes poor. Therefore, conventionally,
A masterbatch with an organic peroxide content of 5% or less impregnated in the powder was used. Conventionally, such a low-concentration masterbatch is used, so the amount of the masterbatch required to improve the fluidity of the resin must be increased, which is a problem in that the manufacturing cost increases. There was also a limit to the improvement of liquidity due to the volume limit.

[0005]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of various studies, talc was used as a base material, the above problems were solved by impregnating this with an organic peroxide, and further, the strength of the obtained resin composition was found to be improved, and the present invention completed. That is, the gist of the present invention resides in a masterbatch of an organic peroxide in which talc having an average particle size of 0.5 to 30 μm contains 0.1 to 50 wt% of an organic peroxide.

The present invention will be described below. The talc used has a particle size of 0.5 to 30 μm. The smaller the particle size, the larger the surface area of the particles, so that a higher concentration masterbatch with better powder properties can be obtained. Therefore, the particle size is preferably 0.5 to 20 μm, particularly preferably 0.5 to 10 μm.
It is better to use the one with μm. The type of organic peroxide used is not particularly limited, and any of those conventionally used for lowering the molecular weight of polypropylene can be used. For example, ketone peroxide (specifically, methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methyl cyclohexanone peroxide, methyl acetoacetate peroxide, acetylacetone peroxide, etc.), peroxyketal ( Specifically, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane,
1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) octane,
n-butyl 4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, etc.), hydroperoxide (specifically, t-butyl hydroperoxide, cumene) Hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, 1,1,
3,3-tetramethylbutyl hydroperoxide, etc., dialkyl peroxide (specifically, di-t
-Butyl peroxide, t-butyl cumyl peroxide, 2,5-dimethyl, 2,5-di (t-butylperoxy) hexane, 2,5-dimethyldi (t-butylperoxy) hexene-3), Diacyl peroxide (specifically, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, 3,
5,5-trimethylhexanoyl peroxide, benzoyl peroxide, etc.), peroxydicarbonate (specifically, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxycarbonate,
Di-n-propyl peroxydicarbonate, di-2-
Ethoxyethyl peroxydicarbonate, dimethoxyisopropyl peroxydicarbonate, di (3-methyl-3-methoxybutylperoxydicarbonate, diallyl peroxydicarbonate, etc.), peroxyester (specifically, t-butylpercarbonate) Oxyacetate,
t-butyl peroxyisobutyrate, t-butyl peroxypivalate, t-butyl peroxy neodecanoate, cumyl peroxy neodecanoate, t-butyl peroxy-2-ethylhexanoate, t- Butyl peroxy-3,5,6-trimethylhexanoate, t
-Butyl peroxy laurate, t-butyl peroxy benzoate, t-butyl peroxy isopropyl carbonate, cumyl peroxy octoate, t-hexyl peroxy neodecanoate, t-hexyl peroxypivalate, t-butyl per Oxyneohexanoate, t-hexylperoxyneohexanoate, cumylperoxyneohexanoate, etc.), acetylcyclohexylsulfonyl peroxide, t-butylperoxyallyl carbonate and the like. Peroxyesters, dialkyl peroxides and peroxyketals are preferred, and t-butylperoxybenzoate and 2,5-dimethyl-2,5-di (t- are preferred.
Butyl peroxy) hexane, n-butyl-4,4-bis (t-butyl peroxy) valerate are used.

As a method for producing a masterbatch, the ratio of the organic peroxide to the base material is 0.1 to 50 parts by weight with respect to 99.9 to 50 parts by weight, preferably 1 to 99 to 80 parts by weight. Be mixed in an amount of up to 20 parts by weight, and after using a mixing stirrer such as a hexshell mixer, preferably a Nauter mixer, to seal the inert gas, be careful not to apply excessive friction or impact to the organic peroxide. Meanwhile, the masterbatch is obtained by stirring for 15 to 30 minutes at a relatively low rotation.

The polypropylene resin used for the masterbatch has a melt flow rate of 0.5 to 100 g / 10.
min homo polypropylene / or ethylene content 0.01 wt% /-10 wt%, preferably 0.1-
Random polypropylene obtained by randomly copolymerizing 5 wt% of ethylene and propylene or / or a polypropylene matrix or a random polypropylene matrix of 70 to 100 wt% is copolymerized with two or more of ethylene, propylene or other α-olefin. It is applied to a block polypropylene containing 0 to 30 wt% of the elastomer component.

The masterbatch is blended in an amount of 0.01 to 10% by weight, preferably 0.1 to 5% by weight with respect to 100% by weight of polypropylene powder, and a heat stabilizer, an antioxidant, etc. added as necessary. Use a batch type kneader such as Labo Plastomill or Banbury mixer, or a continuous type kneader such as an extruder together with the additives.
It is used by kneading under heating at 0 ° C to 280 ° C.

Hereinafter, the present invention will be described more specifically with reference to examples. The physical properties of the examples and comparative examples were measured by the following methods. Melt flow rate (MFR): JISK7210 Flexural modulus: JISK7203

[0011]

【Example】

(Manufacture of masterbatch) 10 wt% t-butyl peroxybenzoate (Perbutyl Z manufactured by NOF Corporation) and talc having an average particle size of 6 μm (High filler # 7 manufactured by Matsumura Sangyo Co., Ltd.)
90% by weight with a Henschel mixer for 15 minutes,
It was a masterbatch. After leaving the obtained masterbatch at room temperature for 1 week, the powder properties of the masterbatch were observed and found to be good (flow angle of repose 54 °).

(Examples 1 to 3 and Comparative Example 1) Heat Treatment of Polypropylene A propylene ethylene block copolymer (ethylene content 5.2 wt%) having a melt flow rate (MFR) of 30 g / min and a density of 0.90 g / cc was added to 0.2 parts by weight of the masterbatch obtained in 1., 0.075 parts by weight of a phenolic antioxidant (Irganox 1010 manufactured by Ciba-Gaigi Co., Ltd.), and a phosphorus-based heat stabilizer (Irgafos 16 manufactured by Ciba-Gaigi Co.)
8) and 0.075 parts by weight of a lubricant (calcium stearate manufactured by NOF CORPORATION) were added and mixed with a Henschel mixer. 40mmφ made by Osaka Seiki Co., Ltd.
Using an extruder of No. 2, a sample was charged from a hopper filled with N ₂ gas, the extrusion temperature was 200 ° C., and the extrusion screw rotation speed was 10
It was extruded at 0 rpm to obtain a polymer in pellet form. (Example 1) The melt flow rate of the obtained polymer was 52 g / 10.
It was min. Similarly, the addition amount of the master batch was 0.3 wt% (Example 2) and 0.5 wt% (Example 3).
When heat treated as, the melt flow rate was 59 each
It was g / 10min and 72g / 10min.

(Injection molding) The polymer heat-treated as described above was injection-molded into a test piece for measuring flexural modulus using an N70B · II injection molding machine manufactured by Japan Steel Works, and the flexural modulus was evaluated. The flexural modulus of each sample was as shown in Table 1.

[0014]

[Table 1]

(Comparative Example 2) The powder of the propylene-ethylene block copolymer used in Examples 1 to 3 and Comparative Example 1 was mixed with 2,5-dimethyl- as an organic peroxide.
2,5-di- (t-butylperoxy) hexane (Perhexa 25B manufactured by NOF CORPORATION) was impregnated to 10% by weight to produce a masterbatch. After the obtained masterbatch was allowed to stand at room temperature for 1 week, the powder properties of the masterbatch were observed. As a result, it was found that a part of the organic peroxide was leached on the surface of the polymer powder.

[0016]

EFFECT OF THE INVENTION By using the organic peroxide masterbatch of the present invention to obtain a low molecular weight product of polypropylene, the fluidity in the transportation pipe during the production of the polymer is excellent, and also during the molding. A highly rigid polypropylene resin composition having good fluidity can be obtained. In addition, the production cost of the resin composition can be reduced, work safety is good, and it is industrially useful.

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Claims (4)

[Claims] 1. A masterbatch of an organic peroxide, which is obtained by adding 0.1 to 50 wt% of an organic peroxide to talc having an average particle size of 0.5 to 30 μm. 2. A masterbatch of an organic peroxide, which is obtained by adding 1 to 20 wt% of an organic peroxide to talc having an average particle size of 0.5 to 20 μm. 3. A polypropylene resin composition having a reduced molecular weight obtained by blending 0.01 to 10 parts by weight of the masterbatch according to claim 1 with 100 parts by weight of polypropylene and heat-treating the mixture. 4. A molecular weight obtained by mixing 0.1 to 5 parts by weight of the masterbatch according to claim 1 with 100 parts by weight of polypropylene, and heating and kneading the mixture at a temperature of 180 to 280 ° C. A polypropylene resin composition having reduced content.