JPS5852335A - Polypropylene composition - Google Patents

Abstract

PURPOSE:To provide a polypropylene composition with high stiffness and low warpage, by incorporating a specific propylene homopolymer or propylene/ethylene random copolymer with a fibrous material. CONSTITUTION:A propylene homopolymer or propylen/ethylene random copolymer, each of them having MFIR <=13, is incorporated with a fibrous material. The polypropylene, MFIR <=13, can be obtained by pyrolisis or molecular breakdown with shearing, pref. by oxidative destruction with an organic peroxide, of polypropylene. Glass fiber or carbon fiber is used pref. as the fibrous material, which accounts for pref. 3-60wt% of the mixture. A composition with high tensile and flexural strength is obtained by including a modified polypropylene grafted with unsaturated carboxylic acids, together with polypropylene, MFIR <=13, and a fibrous material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to edge-containing I-lipropylene compositions with high stiffness and low warpage during molding.

In recent years, polypropylene has been used in electrical products, building materials, automobile parts,
It has been widely used in various mechanical parts. In addition, for applications that require high rigidity, /17 glopyrene may contain various fillers, and if particularly high rigidity is required, it may contain fibrous substances such as glass fiber or Kern fiber. Polypropylene is used.

However, the biggest drawback of such fibrous material-containing polypropylene is that large warpage occurs during molding.

That is, polypropylene alone causes warpage to some extent, but when NI fibrous material is included, warpage becomes even greater. This is because during molding, the rut-like material is oriented in various directions depending on the shape of the metal, molding conditions, etc. For this reason, the shrinkage rate Fi of the molded product is greatly influenced by the orientation of the fibrous material, and as a result, the mold exhibits non-uniform shrinkage, resulting in the generation of a large IJ force.

In this way, IJ gprolene containing a fibrous material has a very high rigidity and has the disadvantage of causing large warpage, so it is suitable for applications such as fields where dimensional stability is required. The application power is s; jt = m.

The original v4 dishes have high rigidity.
As a result of various studies aimed at obtaining a polypropylene composition containing fibrous substances with less generation of
In order to impart high rigidity to the polypropylene composition of the present invention, the polypropylene of the present invention is a propylene homopolymer or a polypropylene composition of the present invention. The content of fibrous material is generally preferably 3 to 60% by weight, particularly 5% by weight, i.e. the content of #&&-like material is 3% by weight in the total composition.
--The following is enough-! 1 property cannot be imparted, 60 weight -
In the above manner, the kneading work is poor and is not industrially practical.

The greatest feature of the present invention is to use polypropylene with an MFIR of 73 or less, %/2.5 or less, in order to suppress the occurrence of warpage during molding of a polypropylene composition containing such a fibrous material. . Therefore, in order to obtain the polypropylene composition of the present invention, the MFIR is 7.
It is necessary to selectively use polypropylene having an MFIR of 3 or less, or to use polypropylene whose MFIR is adjusted to 73 or less. If a composition using polypropylene with an MFIR rating of 13 or less causes warpage during molding, the effect of suppressing warpage can be obtained by further reducing the MFIR of the polypropylene. In addition, the MF of stream propylene in the present invention
The value of IR was determined using a melt flow indexer (equipment) for melt 70-index (MF
I2/1,0> and the melt 70-index (uFt, yyt) of SIi with a load of 3 was measured and substituted into the following equation.

Polypropylene with an MFIR of 13 or less can be obtained not only by selecting a polymerization method, but also by oxidizing polypropylene with a thermal decomposition method, a molecular cutting method using shear force, and especially a peroxide. It is preferably obtained by a decomposition treatment method. In particular, a method in which lipropylene is mixed with an organic peroxide and then melt-flowed using an extruder is preferably used.

Examples of the organic peroxides used include penzoyl oxide, lauroyl oxide, azobisisobutyronitrile, dicumyl oxide, α,
d-bis(1-butyl/#-;f*sydiisopropyl)benzene2,! -Simethylruco, S-di(t-
Butylno(-oxy)hexane, U, S-dimethyl-2
, 5-di(t-butyl/oxy)hexyne-3, di-t-butylhydrooxide, cumenehydrooxide, t-butylhydrooxide, and monooxide. In general, for polypropylene ioo**m with an MFIR greater than 13, the above organic retreatant is 0.0
By adding 0 to 5.0 parts by weight, preferably 0 to 3.0 parts by weight, propylene having an MFIR of 73 or less can be obtained. However, if the amount of organic peroxide added is less than θ, Oθ/1M part, it is not possible to make the MFIR of polypropylene 73 or less, and if it is more than the amount of S, θ, Ml Due to the large rise, handling is difficult and undesirable.

In the present invention, unsaturated carbon is added to polypropylene having an MFIR of 73 or less together with a fibrous material.
By containing the modified polypropylene grafted with 1M, a polypropylene composition that has both high tensile strength and flexural strength is provided. The modified polypropylene used is generally a propylene homopolymer, a 27 dam copolymer of propylene with ethylene, etc., to which acrylic acid, methacrylic acid, maleic acid, or a leopard conductor thereof is grafted in a proportion of 0.0/~5 molar. A compound bond of modified propylene is generally preferred, and the blend bonding of modified propylene is generally between 0.5 and 20 (by weight) 1. Especially /-/S (heavy responsibility)-.

In addition, conventionally known stabilizers, annealing agents, mounting agents, antistatic agents, lubricants, nucleating agents, talc, calcium sulfate, silica, Kaori/, magnesium hydroxide, madanesium silicate, barium sulfate, activated clay, mica, zeolite,
Each of the seven types of fillers may be added as appropriate.

The method for obtaining the polypropylene composition of the present invention is not particularly limited, and can be obtained by mixing polypropylene with an MFIR of 13 or less, a fibrous material, and optionally modified 4tyg σ pyrene. The ingredients may be mixed at the same time, or several types may be mixed in advance and the remaining components may be mixed later.

Then, when pelletizing by extrusion + IkK, the extruder and screw shape are not limited to squares, and a single-screw extruder, twin-screw extruder, or extruder with a kneader may be used. Further, as the screw shape, /ri full flight type screw, Dalmezo Taigue screw, high kneading Taigue screw, etc. are used. When a high tensile strength, bending strength, and bending strength ratio are required, a single-screw extruder using a full-flight Tiege screw is preferably used, which causes less cutting of the composition. As a device for mixing ingredients,
Tumbler set printer, v! Commonly used ones such as j1prene, Henschel mixer, regen mixer, etc. are used. In addition, the desired product may be obtained by modifying a 4-ligropylene composition having an MFIR of 73 or more, mixing lipropylene and an organic peroxide, and then pelletizing the mixture.

The polypropylene composition of the present invention maintains high rigidity and causes less warpage during molding, but this is due to the small ijMFIR, that is, the narrow molecular weight distribution and the small shrinkage rate of propylene. This is one of the factors that reduces the occurrence of warping, but it alone significantly suppresses the occurrence of warping. Therefore, although the exact reason for this is not clear, it is presumed that, in addition to the above-mentioned low hook-up rate, the fibrous material has flow characteristics that allow it to be blended to reduce warping.

In order to explain the present invention more specifically, Examples and Comparative Examples will be given below to clarify the present invention.
these! l! It is not limited to the examples.

In addition, the warp test of the polypropylene composition shown in the Examples and Comparative Examples was conducted by injection molding a disk with a diameter of 15θ and a thickness of
``After leaving it for a while, as shown in Figure 1, the disc's &i1 [i (Figure ■)
And the sled on the back side (Figure ■) is flat Ij! 1, bl, s, a4 for iVC and e, , e2 from the front (Figure 2)
were measured, and these values were substituted into the following equation ([1) to determine the warpage value.

Injection conditions (1) Injection machine used: Nippon Steel H/30Z injection machine Resin temperature
...230℃ Injection pressure...DaOOS15/ Injection speed...-DaOm/sac Mold OA degree Da0℃ In this example fl+ and comparative example, the number of pieces measured was 67 each.
The average value was calculated by taking 0 pieces and entered the value.

Examples / and Comparative Examples / Each of the 49 propylene shown in Table 1 (manufactured by Tokuyama Ichisha, hereinafter also abbreviated as PP) was mixed with a specified organic peroxide, and then put into a 65% extruder (resin (Temperature: 220°C) to obtain polypropylene with an MFIR of 13 or less.
An example of the present invention in which a fibrous material was added to polypropylene having an MFIR of 3 or less and 4 lideroville having an MFIR of 73 or more shown below, and a ratio [9+1] are shown.

As shown in Table 2, glass iron J# (
Manufactured by Nippon Glass Fiber Co., Ltd., product number RES-0,7-T
R37) and Carr/Delicate (manufactured by Toho Peslon Co., Ltd., product number HT^-cb-s) at a predetermined ratio (electricity %).
) and mixed with a tumbler set. Next, the mixture was melt-kneaded and made into an islet using a 1tQ-1t extruder (using a full-flight meter and screw).

A test piece was molded according to ^STM D-790 using the above (respectively /30!) injection molding machine, and the bending elastic modulus (Kt/era2) was measured. were measured.The results are shown below.

As shown in Table 3 of Example 3 and Comparative Example 3, propylene and fibrous materials having various MFIR values as described above, and acrylic #
For No. 1, a modified polypropylene grafted with maleic acid was blended at a predetermined ratio (car weight -), and the same measurements as in Example 1 were conducted. In addition, for modified polypropylene/lipropylene homopolymerization, acrylic acid of S mole is grafted, and for ethylene-propylene random copolymer, no. It is. Thank you for those results 3#! Shown below. In addition, rock wool fiber (TR Nippon Steel Chemical Co., Ltd.,
Varnish fiber FF) was used.

In addition, tensile strength (S/♂) and bending strength (hlcn?)
and 411ν according to ASTMDA 7g and 079011C, respectively.

[Brief explanation of the drawing]

Figure 1 shows a circle f for keeping the warpage constant in the present invention.
Press #. FIG. 1 and FIG. 1 are front views of the front and back surfaces of an injection molded disk, respectively, with respect to the plane. al,
a2, -, and 4 are heights from the plane. Figure III is a plan view of the disk, where e, Vi is the longest one, and l is the length of the longest diameter. Patent Applicant: Tokuyama 1 Sho Co., Ltd. Nippon Steel Chemical Industry Co., Ltd. % 1 Figures Procedures Amendment Written November 79, 1981 Commissioner of the Patent Office Shima 1) Haruki Tono t Indication of Case Patent Application No. 149759 of 1983 2 Title of the invention Polypropylene composition 5 Relationship with the case of the person making the amendment Patent applicant (representative applicant) Address 1-1-5 Mikage-cho, Tokuyama-shi, Yamaguchi Prefecture Number of inventions increased by amendment None & amendment "Detailed Description of the Invention" column and "Drawings" of the subject specification Z Contents of the amendment (1) Correct the Detailed Description of the Specification column j13o and J. (Round) Double press "Table 2" on page 13 of the same document as shown in the attached sheet. (2) Figure 1 of the attached drawing is corrected as shown in the attached sheet. Notes to Table 2 above: 1) Ethylene polymerization of random PP in Table 2 is 0.4 to 1.9 (weight) Xo 2) This shows a comparative example. 261- Ship 1 Figure

Claims (1)

[Scope of Claims] ... A propylene homopolymer with an MFIR of 73 or less
A propylene composition comprising a propylene-ethylene-poor meme copolymer containing a fibrous material. 121 The propylene composition according to claim 1, wherein the propylene homopolymer or propylene-ethylene random copolymer having an MFIR of more than 73 is treated with an organic peroxide to reduce the MFIR to 13 or less. +31 The propylene composition according to claim 111, wherein the fibrous material is glass fiber or Kagen fiber. (4) The ligropylene composition according to claim 11, wherein the content of the fibrous material is 3 to 6011%. 1151 A propylene homopolymer having an MFIR of /3 or less. A 4-ripropylene composition comprising a polypropylene grafted with a random copolymer and a fibrous material and an unsaturated carboxylic acid. Claim 151/
+7 propylene composition.