JPH07145277A - Fluidity improving agent - Google Patents

Abstract

PURPOSE:To obtain a fluidity improving agent composed of a specific di-n- propylsiloxane polymer and capable of improving the fluidity of a polyolefin resin while keeping the impact resistance and molding workability of the resin. CONSTITUTION:This fluidity improving agent is composed of a di-n- propylsiloxane polymer containing the recurring unit of formula and having a weight-average molecular weight of 5,000-50,000. The amount of the improving agent is preferably 0.1-10 pts.wt. based on 100 pts.wt. of polyolefin resin such as PP. The di-n-propylsiloxane polymer is preferably produced by hydrolyzing a di-n-propyldichlorosilane and polymerizing the obtained cyclic di-n- propylsiloxane in the presence of an acid or alkali catalyst.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a flowability improver for polyolefin resins.

[0002]

2. Description of the Related Art Polypropylene resin (hereinafter sometimes abbreviated as PP) has excellent chemical and electrical properties,
Since it has good mechanical properties, it is widely used as a general-purpose resin. However, the flowability and impact resistance of PP are generally in a conflicting relationship, and there is a problem that the impact resistance of high-fluidity PP is low. As a method for solving this problem, a method of blending a PP having a relatively high impact resistance with a low molecular weight PP, a saturated fatty acid metal salt, a fatty acid amide,
A method of adding a lubricant such as dimethylsiloxane is known. However, the former method cannot avoid a decrease in impact resistance. Further, in the latter method, since the added lubricant has a low affinity for PP, there is a problem that the added lubricant bleeds out after molding, or the workability during melt-kneading or molding deteriorates.

[0003]

As described above, there is no known effective method for improving the fluidity of PP without lowering the impact resistance of PP and the workability during molding. It has been strongly desired to develop a fluidity improver having a low bleed-out property.

[0004]

As a result of intensive studies to solve the above problems, the inventors of the present invention have found that when a dinormal propyl siloxane polymer having a specific molecular weight range is added to PP, impact resistance and molding are improved. The inventors have completed the present invention by finding that the workability during processing is not impaired and the fluidity is remarkably improved, and that bleed-out after molding is hardly observed.

That is, the present invention provides the following general formula (1)

[0006]

[Chemical 2]

A fluidity improver comprising a di-normal propyl siloxane polymer having a repeating unit represented by: and a weight average molecular weight of 5,000 to 50,000.

The di-normal-propyl siloxane polymer used in the present invention is represented by the above general formula (1) and has a weight average molecular weight (hereinafter abbreviated as Mw) of 5,000 to 50,000.
The range may be 00. The molecular terminal group of the di-normal propyl siloxane polymer represented by the general formula (1) is not particularly limited, but it is preferable that it is blocked with a substituted silyl group represented by the following general formula (2).

[0009]

[Chemical 3]

However, in the above general formula (2), R ₁
To R ₃ are the same or different substituents. When the substituents R _{1 to} R ₃ in the general formula (2) are specifically illustrated,
Alkyl group such as methyl group, ethyl group, normal propyl group, isopropyl group, normal butyl group, normal octyl group; substituted alkyl such as γ-aminopropyl group, trifluoropropyl group, γ-mercaptopropyl group, methacryloyloxypropyl group A group; an alkoxy group such as a methoxy group, an ethoxy group and a propoxy group; an alkenyl group such as a vinyl group and an allyl group; a halogen atom such as chlorine, bromine and fluorine; a hydroxyl group; and a hydrogen atom. Among these combinations, the trimethylsilyl group and the di-normal-propylhydroxysilyl group are particularly preferable because the raw materials are easily available at the time of polymer synthesis.

The Mw of the dipropyl siloxane polymer used in the present invention should be in the range of 5,000 to 50,000. When Mw is less than 5,000, the crystallinity of the dipropyl siloxane polymer is low, so that the bleed-out property is high, which is not preferable, and the Mw is 50,000.
If it exceeds, the effect of improving fluidity is not exhibited. The Mw referred to here is a polystyrene-equivalent molecular weight measured by gel permeation chromatography (GPC).

The method for producing the di-normal propyl siloxane polymer used in the present invention is not particularly limited, but generally, the cyclic di-normal propyl siloxane obtained by hydrolyzing di-normal propyl dichlorosilane is treated with an acid or an alkali. It is preferably obtained by polymerizing in the presence of a catalyst.

Addition of the di-normal propyl siloxane polymer used in the present invention to a polyolefin resin gives
The fluidity is improved and the impact resistance does not change, as shown in the examples described below. Applicable polyolefin resin of the di-normal propyl siloxane polymer used in the present invention is not particularly limited, ethylene, propylene,
Butene-1,4-methyl-pentene-1, hexene-
It can be applied to homo- or copolymers of α-olefins such as 1, 1, octene 1, those obtained by modifying these polymers with unsaturated carboxylic acids or their anhydrides, and mixtures thereof. Among them, propylene homopolymers and polypropylene-based resins such as block or random copolymers of propylene and α-olefins such as ethylene, butene-1, 4-methyl-pentene-1, hexene-1, octene-1 It is suitable to use. At this time, the amount of the di-normal-propyl siloxane polymer used in the present invention to be added to the polyolefin resin is not particularly limited, and any amount can be added if necessary, but usually 100 parts by weight of the polyolefin resin. On the other hand, a sufficient effect can be obtained by adding about 0.1 to 10 parts by weight.

The di-normal propyl siloxane polymer used in the present invention is a conventionally known stabilizer, if necessary.
Additives such as colorants, antistatic agents, lubricants, weather resistance agents and flame retardants, or various fillers may be used in combination as long as the effects of the present invention are not adversely affected. Examples of fillers preferably used at this time include organic fillers such as rice husks, wood flour, and starch, glass flakes, glass balloons, glass fibers, talc, mica, calcium carbonate, magnesium hydroxide, barium sulfate, And inorganic fillers such as kaolin.

The blending order and blending method for blending the di-normal-propyl siloxane polymer used in the present invention are not particularly limited, and generally, a tumbler blender,
It is carried out by a conventional method using a V-type blender, a Henschel mixer, a ribbon mixer and the like. The mixture thus obtained is melt-kneaded using a known kneader and a molding machine, and then shaped and used.

[0016]

The addition of the di-normal propyl siloxane polymer used in the present invention improves the fluidity of the polyolefin resin without causing bleed-out and without adversely affecting impact resistance and workability during molding. can do. Although the cause of such effects is not clear, it is presumed that the low bleed-out property is due to the extremely high crystallinity of the di-normal-propyl siloxane polymer at room temperature. In addition, regarding that it does not adversely affect impact resistance and workability during molding processing, it is possible that the dinormal propyl siloxane polymer that became a liquid crystal in the molding temperature range has a balanced internal plasticity and external plasticity. It is presumed to be the cause.

[0017]

According to the present invention, it becomes possible to obtain a polyolefin resin having high fluidity and excellent impact resistance. This means that the product can be made thinner and the molding cycle can be shortened. In particular, it is an epoch-making thing for polypropylene resin, which was difficult to maintain high impact resistance and high fluidity. Is.

[0018]

EXAMPLES In order to describe the present invention more specifically, examples and comparative examples will be described below, but the present invention is not limited to these examples.

The resins used in this example and comparative examples are shown below.

(A) Polypropylene resin P1: Homo PP (PN120; MF manufactured by Tokuyama Soda Co., Ltd.)
R = 1.7 g / 10 minutes) P2: Block PP (PN670 manufactured by Tokuyama Soda Co., Ltd.)
Ethylene content 3.9wt%, MFR = 22g / 10
Min) P3: Block PP (PN640 manufactured by Tokuyama Soda Co., Ltd .;
Ethylene content 3.6 wt%, MFR = 6.6 g / 10
Min) (B) Dinormal propyl siloxane polymer (only Mw is described) PS1: Mw = 10,000 PS2: Mw = 42,000 PS3: Mw = 2,000 PS4: Mw = 220,000 The siloxane polymer was synthesized by the following method. First, in a hexane solvent, dichlorosilane gas and propylene gas were simultaneously blown in the presence of a chloroplatinic acid catalyst to react with each other to synthesize dinormal propyldichlorosilane. The isolated di-normal propyl dichlorosilane was further hydrolyzed to synthesize a di-normal propyl siloxane cyclic trimer. Hexamethyldisiloxane, which is a molecular weight regulator, was added to the purified cyclic trimer according to the target molecular weight, and polymerization was carried out in the presence of a trifluoromethanesulfonic acid catalyst. The polymerization product was washed with a solvent to remove residual monomers and low-molecular weight components, and dried to obtain the above-mentioned various di-normal-propyl siloxane polymers having a molecular end blocked with a trimethylsilyl group.

(C) Conventional fluidity improver R1: dimethylsiloxane polymer (KF-96-300 manufactured by Shin-Etsu Chemical Co., Ltd.) R2: low molecular weight PP (wax PP23 manufactured by Hoechst)
0) R3: erucic acid amide The fluidity is as follows: injection temperature 240 ° C, injection pressure 40 kg /
cm ² and mold temperature of 40 ° C. were used to evaluate the flow length measurement results using a mold with a thickness of 2 mm, and the impact resistance is JIS K
It was evaluated by Izod impact strength at 23 ° C. measured according to 7110.

Regarding the bleed-out property, the Izod test piece was allowed to stand in a gear oven kept at 120 ° C. for 3 days and then visually observed to find that the surface property was unchanged, and the surface was sticky. Was evaluated as x.

Examples 1 to 7 and Comparative Examples 1 to 9 The respective resins and additives weighed according to the formulations shown in Tables 1 and 2 were dry blended, and then melt-kneaded through an extruder to form pellets. The pellets thus obtained were used to evaluate fluidity, impact resistance and bleed-out property. The results are shown in Table 1 and Table 2 together.

[0024]

[Table 1]

[0025]

[Table 2]

Claims (1)

[Claims] 1. The following general formula (1): And a weight average molecular weight of 5,000
A rheology improver comprising a di-normal propyl siloxane polymer of 0-50,000.