JPS5825342A - Production of non-rigid polyolefin resin composition - Google Patents

Abstract

PURPOSE:To produce the titled resin compsn. having excellent injection moldability and mechanical strength, by granulating a mixture of polypropylene, an olefin copolymer rubber and a mineral oil, adding an org. peroxide thereto, and then granulating the mixture while kneading. CONSTITUTION:50-80pts.wt. crystalline propylene homopolymer resin (A) having an MFR of 0.5-3 at 230 deg.C, 50-20pts.wt., monoolefin compolymer rubber (B) such as an ethylene/propylene copolymer rubber, and 5-20pts.wt. (per 100pts.wt. of the combined amount of components A and B) mineral oil (C) are melt-mixed for 5-10min by means of a roll mill, cooled and granulated. The granules and an org. peroxide such as 2,5-dimethyl-2,5-di(t-butylperoxy) hexane are mixed together to deposit 0.05-0.5wt% org. peroxide on the surfaces of the granules. Then the resulting granules are kneaded at 170-250 deg.C by using an extruder type kneader, and eextruded through a die to continuously granulate them.

Description

Detailed Description of the Invention The present invention has improved injection moldability (fluidity) by using monoolefin copolymer rubber and crystalline polypropylene as main components.
, i.e. high melt flow rate index (VFR
) and a method for producing a soft olefin resin composition having excellent mechanical strength.

Soft olefin resin, whose main components are monoolefin copolymer rubber and crystalline polypropylene, has a low specific gravity, excellent heat resistance and weather resistance, and is a relatively inexpensive material, so it is used mainly in the automotive parts field from metal parts. RIM in AB8 resin has been rapidly attracting attention in recent years for the purpose of reducing weight and cost by replacing urethane parts, improving component life by replacing urethane parts, and reducing costs.

In particular, replacing large parts such as automobile pan bars and instrument panels with soft olefin resins has become the industry's go-to for weight reduction and cost reduction.

However, soft olefin resins that are mainly composed of monoolefin copolymer rubber and crystalline polypropylene have rapid fluidity due to the rubber component they contain, making it impossible to mold large products, or even if it is possible, flow marks occur. The result was not satisfactory due to the following problems. The purpose of the present invention is to significantly improve the injection moldability, that is, the fluidity, of conventional soft olefin resins mainly composed of monoolefin copolymer rubber and crystalline polypropylene, without completely losing mechanical strength. It is possible to mold large parts.

For example, conventional olefin copolymer rubber, crystalline polypropylene, organic peroxide non-crosslinked hydrocarbon rubber, and/or mineral oil are heat-treated in the presence of organic peroxide to produce good reactants, and further olein-based plastics are used. The dilution method (Japanese Patent Publication Nos. 56-15740 and 56-15743) has poor injection moldability, and the object of the present invention cannot be achieved.

Conventional soft olefin resins, which are mainly composed of crystalline polypropylene and monoolefin copolymer rubber, have problems with injection moldability, such as the occurrence of flow marks when injection molding large parts because they contain rubber components. At present, its uses are largely limited. Therefore, injection moldability has become an important issue in this industry.

As a method for improving the injection moldability (fluidity) of soft olefin resins made of crystalline polypropylene and monoolefin copolymer rubber, it is possible to use simple KFi or high MFR crystalline polypropylene as raw materials, or to add mineral oil-based softeners. However, when high MFR crystalline polypropylene is used, the layer peeling phenomenon on the surface of the molded product, which is thought to be caused by the marked difference in fluidity from that of monoolefin copolymer rubber, may cause dust,717 and the addition of mineral oil-based softeners. However, it was not satisfactory due to the disadvantage that heat deformation resistance was significantly impaired.

The present inventors have worked hard to improve the injection moldability, which is a drawback of conventional soft olefin resins, and to make it possible to apply this material to large injection molded parts. We have discovered that it is possible to achieve the objective by employing a manufacturing method, and based on this knowledge, we have accomplished the present invention. That is, the present invention uses 230°C as a raw material.
VFR measured at Fi is preferably 0.5 to 3.05.
o, 5 to 2.0 crystalline propylene homopolymer resin (2
) SO~80 parts by weight, monoolefin copolymer rubber @50
~20 parts by weight, using 5 to 20 parts by weight of mineral oil 0 to 100 parts by weight, and the manufacturing method is ■, @
, C) After uniformly melting and mixing the entire amount of the ingredients in advance, it is shredded into granules, and organic peroxide is applied on the surface of the granules by 0.05 to 0.0
, S weight-1 preferably ij O, 2-0.4 weight-1
This is a method in which the organic peroxide is uniformly deposited and then continuously granulated by decomposing the organic peroxide in an extruder-type multi-wire machine. Here, when using a crystalline propylene nest-polymer resin with a radius greater than 3.0, the mechanical g! If a crystalline propylene/ethylene copolymer resin (TRT) is used, the degree of A is significantly impaired, and the fluidity is not improved and the injection moldability is unsatisfactory.

In the composition ratio of component (2), @, component (2) is 50
If the amount of component (2) is less than 1st, 70 marks will appear on the injection molded product, and if the amount of component (2) exceeds 80% by weight, the product will not have enough flexibility and will crumble even though it is a soft olefin resin. . If the amount of mineral oil C) added exceeds J weight -, the molded product becomes sticky and the heat deformation resistance deteriorates. When the weight is less than 5 -, the effect of improving injection moldability is not sufficient. When the amount of organic peroxide is less than 0% by weight of O, OS, the fluidity improving effect is not sufficient, and furthermore, the degree of crosslinking of the monoolefin copolymer rubber is low, and the heat resistance of the product is poor.

If it exceeds 0.5% by weight, the MFR of the reaction product increases significantly, making granulation during production difficult.

Regarding the manufacturing method, it is impossible to achieve the objective using any method other than the method of the present invention. In other words, ingredient prisoners.

■, The flowability is improved by a method in which the composition ratios of O and organic peroxide are exactly the same, and one part of component (2) and ■, 01- are treated with organic peroxide in advance, and diluted with the remaining Q component (9). 70 marks are generated on the molded product.

After preliminarily melting and mixing one part of the six-component mixture with (B) and C), granulation is carried out, and the mixing of the remaining 90 components and the attachment of organic peroxide are carried out simultaneously, and the organic peroxide is removed in an extruder. This method cannot be widely used because the mechanical strength is lower than that obtained by the method of the present invention.

The present invention will be explained in more detail. Pre-heated roll, Banbury construction f+, pressurized! A predetermined amount of crystalline polypropylene WI, monoolefin copolymer rubber (2), and mineral oil C5 are put into a kneader such as a kneader, and mixed for 5 to 10 minutes. The uniformly melted and mixed mixture is taken out and made into a sheet while being cooled and solidified using a roller, and this sheet is made into pellets using a cube pelletizer. Next KV
Pellets and a predetermined amount of organic peroxide are placed in a mold blender, tumbler, or Henschel mixer, and mixed until the organic peroxide is uniformly attached to the surface of the pellets. The mixture is heated to about 170 to 250°C and kneaded in a conventional extrusion mode to decompose the organic peroxide, and at the same time, the reaction product flowing out from the die is cooled and solidified to continuously produce the mixture. By granulating, a soft olefin resin composition with excellent injection moldability and mechanical strength can be obtained.

In the above steps, various pigments, heat stabilizers, weather stabilizers, and fillers may be added at any stage.

Next, components (A), @), C used in the present invention
) and organic peroxides will be explained. Ingredient (A) Fi
, isotactic or syndiotactic polypropylene with a high degree of crystallinity, which is produced by polymerizing propylene using a Ziegler-Ivy catalyst, and has an MFR measured at 230°C in the range of 0.5 to 3.0. . Component @ is an essentially amorphous random copolymer made by copolymerizing two or more monoolefins or at least one polyene that can be further copolymerized with a Ziegler-Nack catalyst consisting of a combination of a vanadium compound and an aluminum compound. It is a polymer. Generally, ethylene/propylene copolymer rubber, ethylene/propylene/dicyclopentadiene copolymer rubber, ethylene/propylene/ethylidenenorbornene copolymer rubber, ethylene/propylene/1,4-hexadiene copolymer rubber Component (e) is an aromatic, naphthenic, or paraffinic mineral oil that is commonly used as a rubber processing aid or softener, and is a mixture of these mineral oils. It's okay. As an organic peroxide, 2,5-dimethyl 2,5-di(t-
butylperoxy)hexyne-3, di-t-butylperoxide, 2゜5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butylperoxydiisopropylbenzene, dikune peroxide, t-butylperoxybenzoate, 1.1-bis(t-
Examples include butylperoxy)-3,3,5-)limethylcyclohexane, 2,4-cyclopenzoylmonoxide, benzoyl peroxide, p-chlorobenzoyl peroxide, etc., but they are more suitable for high-temperature decomposition. Types are used selectively.

Next, to describe the effects of the present invention, Example 1-2 described below
, 'm1 of crystalline polypropylene resin in Comparative Examples 1 to 5.
The properties of the reaction product obtained by the method of the present invention are shown by changing st, but resins other than the present invention, that is, propylene monopolymer resins with high VFR, have a The degree (El) is 50 to 70 degrees and there are 4
It is significantly lower than 530 to 5704 of the present invention (Example 1.2 and Comparative Example S = Z), and when crystalline propylene-ethylene copolymer resin is used instead of crystalline polypropylene resin, the production The elongation at break of the product was extremely low (comparative example 3%), the fluidity (■゛R), and the molded appearance (flow marks) were poor. (Comparative Example 5).

Comparative Example 6.7 shows the properties of a product obtained by a method different from the production method of the present invention. A composition obtained by diluting and mixing the product obtained by reacting an organic peroxide with the remaining crystalline polypropylene resin in an inkizer is mechanically processed.
ls[ is excellent, but the injection molded appearance is extremely poor (Comparative Example 6). In addition, part of the crystalline polypropylene resin, monoolefin copolymer rubber, and mineral oil were mixed in advance.
After melting and mixing in a kisser, the organic peroxide is attached to the square pellets, and at the same time, the remaining crystalline polypropylene is added.The resulting tri-blend is mixed in an extruder. The elongation at break and the injection molded appearance were significantly worse than those of the present invention (Comparative Example 7).

Next, the present invention will be explained in more detail with reference to Examples.

The details of each of the six components used in the following Examples and Comparative Examples are as follows.

l) Crystalline polypropylene resin PP 11+- (MFR; 1.o, density: 0
．． 90, propylene homopolymer) PP (21...
(MFR; o, a, #I)
PP (31-(MFR: 11.0, #
#)PP (41...(MFR;
s, o, l l) PP 16
+・-(■ Condolence; 2.7, l l
)PP 171...-(MFR; t, s, l
l)2) Ethylene/propylene/
Ethylidene norbornene copolymer rubber (EPIl□) EP 111-... (propylene content; 28 wt%
, iodine number; 15, extension oil; paraffin oil sopm
, ML1+4100 = 50) EP (2t...(propylene content; 43wt)
Iodine value: 15, ML1+4100 = 105) EP (31-(Propylene content; 43 wt rumor, Iodine value: 26, ML1+4 Zoo = 83) EP!41.:・(Propylene content; 28 wt%
, iodine value: 15, MLl, , 10G = 90) 3) Mineral oil oil (1) - paraffinic process oil ltl; 0
．． 8971, kinematic viscosity: No. 19 c+++t (37,8
℃), viscosity index; 92.0) 4) Organic peroxide PO(1)-...2-dimethyl-2,5-di(t-butylperoxy)hexane Examples 1 to 5, Comparative Examples 1 to 5 70 parts by weight of crystalline polypropylene resin (types are shown in Table 1), ethylene propylene/ethylide 7 norbornene copolymer rubber blade layer (types shown in Table 1), mineral oil 15 parts
Parts by weight were mixed for 5 minutes at a rotor rotation speed of 6 Orpm in a Banbury mixer (manufactured by Goshijuko) with an internal volume of 4 tons and preheated to 110'C. Take out the mixture 1
A sheet with a thickness of about 2 cm was made by rolling a 0 inch roll. This sheet was cut into a full-width cut using a pelletizer K to form a pellet with a length of about 2 cm. 0.35 parts by weight of the organic peroxide POfl were added to 1 part by weight of the pellets (100 parts by weight) in a tumbler mixer and mixed for 5 minutes to uniformly adhere the organic peroxide to the surface of the pellets. Next, the cylinder temperature was set to 200℃,
The organic peroxide-adhered pellets were kneaded and granulated using a 55φ vented extruder (full-flight screw). (The above manufacturing method is considered a manufacturing corporation.) The obtained good product is put into an injection molding machine (3.5 ounces, molding ml' at 240°C).
) was molded into a test piece of 100 x 100 x 2vnm and subjected to evaluation of physical properties.The evaluation results are shown in Table 1.

Comparative Example 6 Using the same raw materials as in Example 5, a soft olefin resin was produced according to the following procedure. That is, P P 11
140 Denryu parts, EP 14160 parts by weight, oil (11
After kneading part by weight for 3 minutes in a Banbury mixer preheated to 110°C, the POII was 0.62.
The product was taken out from the Banbury mixer and made into a sheet with a thickness of about 2M using a 10-inch roll, and then cut into a sheet with a thickness of about 211W using a cube pelletizer. It was made into a beret. This pellet 56.5 parts by weight, PP11143.5
Parts by weight were put into a tumbler/mixer and tri-blended for 5 minutes, then kneaded and granulated using a s5φ5φ vent extractor. (The above manufacturing method is referred to as manufacturing method B.) Physical property evaluation was performed in the same procedure as Examples 1 to S and Comparative Examples 1 to 5. Physical properties and bond values are shown in Table 2.

Comparative Example 7 After mixing PP (1140 parts by weight, EP (4160 parts by weight), and oil (1130 parts by weight) in a Banbury mixer preheated to 110°C for S minutes, the mixture was deposited and sealed with a 10-inch roll. ) K L cut into pellets using a pelletizer.This pellet is 56.5
Parts by weight, PP tll t” 43.5 parts by weight, P 0
Parts by weight were added to a tumbler-fist mixer and mixed for 5 minutes to uniformly adhere Po. ■The adhesion mixture can be mixed and granulated using a 55φ pent extruder.

(The above manufacturing method is referred to as manufacturing method C.) The physical property evaluation results are shown in Table 2. Implementation shown in Table 2? l
I rs , the final products of Comparative Examples 6 and 7 have exactly the same raw material components and composition ratios.

Examples 6 to 11 PPtll, EPf41, oil (1), P as raw materials
Table 3 shows an example in which the composition ratio of the raw materials was changed depending on the manufacturing company.

The test methods for the physical property evaluation items shown in Tables 1 to 3 are listed below.

1) MFR; ASTM D 1238 (230℃
)2) Shore D hardness; Af3Thl D 2240
3) Flexural modulus; ASTM D 7904) T,
(Strength at break); JISK aaot5) E
l (elongation at break): 1 6) Flow mark; visually judged injection molded plate of 10100 x 100 x 2. (None 20, Slightly present: Δ, Significantly present: ×) 7) Sticky; 10100 x 100 x 2 injection molded plates stacked on top of each other and then with no resistance when pulled apart; ○, with some resistance;, sticky. :×.

E 2 Table E 3 Table

Claims (1)

[Claims] Crystalline propylene homopolymer resin (A) having a melt flow rate index (MFR) of 0.5 to 3.0 measured at 230°C, t-50 to 80 parts by weight, monoolefin copolymer rubber (B) 50-20 parts by weight, ■◆01
) After uniformly melting and mixing 5 to 20 parts by weight of mineral oil 0 to 100 parts by weight, the mixture is granulated and the surface of the granules is
Injection moldability characterized by uniformly depositing 0.05 to 0.5 parts by weight of an organic peroxide and granulating it continuously in an extruder-type mixer 9 while allowing the organic peroxide to act. Manufacturing method of soft polyolefin resin composition with excellent (fluidity) and mechanical strength fK