JPS6320862B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polypropylene resin composition, more specifically, a polypropylene resin with a specific composition of ethylene and α.
-Regarding a polypropylene resin composition containing a specific proportion of olefin/nonconjugated polyene copolymer rubber and having excellent rigidity, impact resistance, moldability, etc. It is well known that polypropylene resin has excellent mechanical properties, transparency, chemical resistance, processability, etc., and is therefore used for a wide range of purposes. However, polypropylene resin has drawbacks such as poor impact resistance and low-temperature embrittlement. Therefore, many methods have been proposed to improve these drawbacks, including the addition of ethylene or other α-
Typical examples include a method of copolymerizing olefin and a method of blending a soft resin or rubber-like substance with polypropylene resin. Each of these methods has advantages and disadvantages, but compared to the former copolymerization method, the latter blending method produces polypropylene resin and a soft resin or rubbery substance separately, making it possible to produce a resin composition with desired properties. Since the mixture can be mixed using an extruder or the like, resin compositions having various desired properties can be easily obtained, and the price of the resin composition does not increase significantly even when produced on a small scale. The improver used in the above blending method is ethylene/propylene copolymer rubber
7088, Japanese Patent Publication No. 37-8483), ethylene/1-butene copolymer with 80 mol% or less of ethylene units (Japanese Patent Publication No. 24526, 1972), butyl rubber (Special Publication No. 10341, 1972)
), polyisobutylene (Special Publication No. 35-10640),
Ethylene/acrylate copolymer (Special Publication 1979-
17364) etc. have been proposed so far. The blending of these rubbers and copolymers certainly improves impact resistance, low-temperature embrittlement, etc., but it also improves other properties of polypropylene resin, such as mechanical properties such as yield stress and rigidity,
It also had other drawbacks such as loss of transparency, and was not fully satisfactory. Also, as a modifier used in blending methods,
Ethylene-propylene-diene copolymer published in JP-A-Sho
Although it is disclosed in the specification of No. 50-37843, the impact resistance of the resin composition blended with polypropylene resin is not sufficiently improved, and the mechanical properties such as tensile strength at break are also inferior. Furthermore, since the above copolymer has low crystallinity, it is difficult to pelletize it, and even when it is pelletized, it has poor handling properties such as easy blocking, and it is necessary to obtain a copolymer having flexibility that increases the impact strength of the resin composition. In the area,
It was not possible to obtain a copolymer with excellent handling properties, and there were drawbacks such as reduced processability. As a proposal to improve the impact resistance and low-temperature embrittlement of polypropylene resin without significantly impairing its mechanical strength, ethylene containing 85 to 95 mol% of ethylene was proposed.
A polypropylene resin composition in which a 1-butene random copolymer is blended with a polypropylene resin together with low-density polyethylene is disclosed in JP-A-52-72744 and JP-A-Sho.
No. 52-95759. This proposal is superior to other methods in that it can improve impact strength and low-temperature embrittlement without significantly impairing the mechanical properties of polypropylene.
-Resin compositions made by blending a butene copolymer with polypropylene resin have a high melt viscosity in the molding temperature range, resulting in an increase in resin pressure during molding or the occurrence of rough flow marks on molded products, resulting in decreased processability. The inventors have discovered that new problems arise, particularly when relatively high melt index polypropylene resins are used. Thus, an object of the present invention is to provide a polypropylene resin composition that has excellent processability and impact resistance without significantly impairing the mechanical strength of the polypropylene resin, by a blending method. Therefore, the present inventor discovered that ethylene and carbon atoms of 4 to 10
It is obtained by blending a specific amount of ethylene/α-olefin/non-conjugated polyene copolymer rubber with a polypropylene resin in a molar ratio (ethylene/α-olefin) of about 86/24 to about 95/5. The polypropylene resin composition has an ethylene content of
It has been found that the aforementioned JP-A-52-95759, which uses 85 to 95 mol% ethylene/1-butene random copolymer, inherits the advantages of the disclosed composition and greatly improves moldability. We have arrived at the heading Invention. That is, in the present invention, the polypropylene resin (A) and the molar ratio of ethylene to α-olefin having 4 to 10 carbon atoms (ethylene/α-olefin) are approximately 86/24.
Ethylene/α-olefin/non-conjugated polyene copolymer rubber with a ratio of 95/5 to about 95/5 and an iodine value of 4 to 40.
(B), and the weight ratio of the polypropylene resin (A) to the copolymer rubber (B) ((A)/(B)) is about 50/50 to about 95/5. The present invention relates to providing a polypropylene resin composition having excellent impact resistance, moldability, etc. Other objects of the invention according to the following description of the invention,
The benefits will be better understood. The polypropylene resin (A) of the present invention is a crystalline polypropylene, and usually has an isotactic index of about 75.
% or more, preferably about 85% or more, more preferably about 90% or more. Here, the isotactic index is the content insoluble in boiling n-heptane expressed in weight percent. The melt index (230°C, ASTM D-1238) of the polypropylene resin (A) is usually about 0.1 to about 30, preferably about 1 to about 25, particularly about 5 to about 20. The effect is remarkable. In the present invention, the polypropylene resin (A) has a molar ratio of ethylene to an α-olefin having 4 to 10 carbon atoms (ethylene/α-olefin) of about 86/24 to about 95/5, and an iodination of 4 to 40%. of ethylene α
- Blend olefin/non-conjugated polyene copolymer rubber (B). The blending of this copolymer rubber (B) constitutes the most important structural part of the present invention. A desirable balance between the mechanical strength, impact resistance, and low-temperature embrittlement resistance of the polypropylene resin composition cannot be obtained by simply blending the ethylene/propylene copolymer rubber as proposed in the past. Also, simple ethylene and α having 4 to 10 carbon atoms
- In the formulation of copolymer rubber with olefin, if the ethylene content is low, the desired balance of the above physical properties cannot be obtained, and the molar ratio of ethylene and α-olefin (ethylene/α-olefin) is only about
Even with the copolymer rubber in the range of 86/24 to about 95/5, processability is poor. That is, the copolymer rubber (B) of the present invention has a molar ratio of ethylene and α-olefin having 4 to 10 carbon atoms within the above-mentioned specific range, and also has a non-conjugated polyene component copolymerized with ethylene/α-olefin. When the polypropylene resin composition of the present invention is an olefin/non-conjugated polyene copolymer and is a rubber having an iodine value of 4 to 40, the polypropylene resin composition of the present invention has excellent mechanical strength, impact strength, low temperature embrittlement resistance, etc. gives a well-balanced molded product. α-olefin, which is an essential component of the ethylene/α-olefin/nonconjugated polyene copolymer rubber (B), has 4 to 10 carbon atoms. Specifically, 1-butene, 1-pentene, 1-hexene,
4-methyl-1-pentene, 1-octene, 1-
Examples include decene and mixtures thereof, and 1-butene is particularly preferred. And the molar ratio of ethylene units to α-olefin units (ethylene/α-
olefin) is about 86/14 to about 95/5, preferably about 88/12 to about 95/5. The molar ratio is approx.
When the number of ethylene units exceeds 95/5, the impact resistance of the composition of the present invention decreases, resulting in a content of about 86/24.
If it is less than this, there will be a disadvantage that the rigidity will decrease.
Copolymer rubbers outside the above range are excluded from the present invention. Propylene having 3 carbon atoms is excluded as α-olefin here because if propylene is used as a constituent unit of copolymer rubber, the impact resistance of the resin composition will not be sufficiently improved as mentioned above, and the tensile point at break will be insufficient. This is because the mechanical properties of the copolymer rubber are poor, and the handling properties of the copolymer rubber are also poor, resulting in a decrease in processability. α
- When using an olefin with 4 to 10 carbon atoms, compared to using propylene,
A resin composition with further improved impact resistance, excellent mechanical properties such as tensile strength at break, and well-balanced physical properties can be obtained, and the copolymer rubber itself has high crystallinity, which improves pellet handling properties. It has excellent properties and can be pelletized and handled in a wide range of flexibility, resulting in good processability. The intrinsic viscosity (η) of the ethylene/α-olefin/nonconjugated polyene copolymer rubber (B) of the present invention is approximately 0.6 as measured by a multipoint method at 135°C in decalin.
from about 6.0 dl/g, preferably from about 0.8 to about 4.0
dl/g, more preferably about 1.0 to about 3.0 dl/g
It is. If [η] is less than about 0.6 dl/g, impact resistance may decrease or moldability may be poor. Moreover, if it exceeds about 6.0 dl/g, problems such as a decrease in the impact resistance of the resin composition and poor moldability due to a decrease in fluidity will occur. Ethylene-α-olefin used in the present invention
The amount of the non-conjugated polyene in the non-conjugated polyene rubber is usually about 4 to about 40, preferably about 8 to about 40, more preferably about 8 to about 30, expressed in terms of iodine number. Specifically, the non-conjugated polyene component includes 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,
Chain nonconjugated dienes such as 6-octadiene, cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2 -Norbornene, 6-chloromethyl-5-
Cyclic nonconjugated dienes such as isopropenyl-2-norbornene, 2,3-diisopropylidene-5
-Norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-
Typical examples include trienes such as 2,2-norbornadiene, 1,3,7-octatriene, and 1,4,9-decatriene. Suitable non-conjugated polyenes are 1,4-hexadiene and cyclic non-conjugated dienes, especially dicyclopentadiene and 5-ethylidene-2-norbornene. Further, the copolymer rubber (B) of the present invention is preferably a random copolymer rubber. The ethylene/α-olefin/non-conjugated polyene copolymer rubber used in the present invention can be produced by a conventional method for producing ethylene/propylene/non-conjugated polyene copolymer rubber. That is, it is produced by using a Ziegler catalyst such as a soluble vanadium compound and an organoaluminum compound in a medium, and supplying ethylene, an α-olefin having 4 to 10 carbon atoms, a nonconjugated polyene, and hydrogen gas as a molecular weight regulator. be done. Examples of media include aliphatic hydrocarbons such as pentane, hexane, heptane, octane, and kerosene, alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene, toluene, and xylene, chlorobenzene, and tetrachloride. Carbon, halogenated hydrocarbons such as tetrachloroethylene, trichlorethylene, ethyl chloride, methylene chloride, and dichloroethane can be used alone or in combination. Examples of soluble vanadium compounds include vanadium tetrachloride, vanadyl trichloride, vanadium triacetylacetonate, vanadyl acetylacetonate, vanadyl trialkoxide VO(OR) ₃ (R here represents an aliphatic hydrocarbon group), halogenated vanadyl alkoxide
VO(OR) _o X _3-o (here R is an aliphatic hydrocarbon group,
X represents a halogen atom, and O<n<3. ) can be used alone or in combination. On the other hand, organoaluminum compounds have the general formula R _n AlX _3-n (where R is an aliphatic hydrocarbon group,
X represents halogen, and 1≦m≦3. )
Compounds represented by, for example, triethylaluminum, diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, etc. can be used alone or in combination. The weight ratio ((A)/(B)) of polypropylene resin (A) and copolymer rubber (B) is about 50/50 to about 95/5, preferably about 70/30 to about 95/5. . Approximately 50/
If the amount of polypropylene resin (A) is less than 50, the mechanical strength of the molded product will be poor, and if it exceeds about 95/5 and the amount of copolymer rubber (B) is low, the molded product will have poor impact resistance and low-temperature embrittlement. inferior to The composition of the present invention may further contain heat stabilizers, ultraviolet absorbers, lubricants, nucleating agents, antistatic agents, slip agents, antiblocking dyes, and the like. In addition, low-density polyethylene with a melt index (190°C, ASTM D1238) of about 0.1 to 30 obtained by radical polymerization of ethylene under high pressure with a density of about 0.94 g/cm ³ or less is mixed with polypropylene resin (A) and ethylene α- By adding about 1 to about 15 parts by weight to 100 parts by weight of the total amount of olefin/nonconjugated polyene copolymer rubber (B), even greater transparency can be imparted to the molded product. The composition of the present invention can be prepared using any known mixer, such as a V-mixer.
The preparation can be carried out using a combination of a mold blender, ribbon blender, Henschel mixer, etc., and a mixer such as a conventional extruder, calender roll, Banbury mixer, etc. The polypropylene composition of the present invention has good processability, impact resistance, and low-temperature embrittlement resistance, and maintains good mechanical properties and chemical resistance, which are the original properties of polypropylene, and is suitable for any use of polypropylene. It can also be used for It is particularly suitable for fields where impact resistance is required, such as injection molding materials, food packaging films, sheets and blow molding materials, and is particularly excellent as an injection molding material. The composition of the present invention can also be suitably used in applications in which it is laminated with nylon or polyester films. Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples unless the gist thereof is exceeded. In addition, each measurement value in Examples and Comparative Examples was measured by the following method. 1 Stress at yield point (YS), tensile strength at break (TB) and elongation at break (EL) 150mm by injection molding machine under the following injection conditions
A 120 mm x 120 mm sheet was formed and measured using a Schottper type tester according to the method specified in JIS K6758. Primary injection pressure 1000Kg/cm ³ , cycle held for 5 seconds Secondary pressure 800Kg/cm ² , cycle 5 seconds Injection speed 40mm/sec Resin temperature 260℃ 2 Spiral flow Using a semicircular spiral mold with a strand radius of 2.4mm, Molding was performed under the above injection conditions and the strand length was measured. 3 Izot impact strength Tested in accordance with ASTM D256 in an atmosphere at 23°C. In the above, the spiral flow is a measure of ease of flow, and a high value indicates easy flow and good workability. Examples 1 to 3 Polypropylene resin with isotactic index 91 and melt index (230°C) 13 and ethylene 1
- Butene/dicyclopentadiene random copolymer rubber [molar ratio of ethylene and 1-butene (ethylene/1-butene) 92/8, iodine value 10, intrinsic viscosity [η] = 1.1] in the proportions shown in Table 1. After mixing in a V-type blender for 5 minutes, the resin temperature was 255°C.
After pelletizing using a 65 mmφ extruder, YS (Kg/cm ² ), EL (%), spiral flow length (cm), and Izot impact strength were measured using the methods described above. The results are shown in Table 1. Comparative Examples 1 and 2 The same operations as in Example 1 were performed except that the blending ratios of the polypropylene resin and copolymer were set as shown in Table 1. The results are shown in Table 1.

[Table] (1) Comparative examples of ethylene/1-butene/dicyclopenta diene random copolymer rubber 3, 4 In Example 2, the molar ratio of ethylene and 1-butene (ethylene/1-butene) was 97/3 (comparative example). 3) The same operation was performed except that 80/20 (Comparative Example 4) ethylene/1-butene/dicyclopentadiene random copolymer rubber was used. The results are shown in Table 2 together with Example 2. Note that other physical property values of the copolymer rubber used in this comparative example are listed in Table 2. Comparative Example 5 In Example 2, the molar ratio of ethylene and 1-butene (ethylene/1-butene) was
The same operation as in Example 2 was carried out except that 92/8 ethylene-1-butene random copolymer rubber was used.
The results are shown in Table 2. Other physical properties of the copolymer rubber are shown in Table 2.

[Table] (1) Ethylene/1-butene copolymer rubber (does not contain polyene component)
Comparative Examples 6-8 In Examples 1-3, ethylene-propylene-dicyclopentadiene random copolymer rubber having the same flexibility as component (B) [mole ratio of ethylene and propylene (ethylene/propylene) 86/
14, iodine number 10, intrinsic viscosity [η] = 1.1, but the same operation was performed, and TB was obtained by the method described above.
(Tensile strength at break) and Izod impact strength were measured, and the results are shown in Table 3 together with Examples 1 to 3.

【table】

[Table] From the results in Table 3, in the case of the same flexibility, Example 1
-3 are superior to Comparative Examples 6 to 8 in both TB and Izot impact strength, and when the Izot impact strength is the same, TB is larger in the example than in the comparative example, and when TB is the same, The Izotsu impact strength of the example is higher than that of the comparative example.
It can be seen that the examples have an excellent balance of physical properties.

Claims (1)

[Claims] 1. The polypropylene resin (A) and the molar ratio of ethylene to α-olefin having 4 to 10 carbon atoms (ethylene/α-olefin) are about 86/14 to about 95/5.
It consists of an ethylene/α-olefin/non-conjugated polyene copolymer rubber (B) with an iodine value of 4 to 40, and the weight ratio of the polypropylene resin (A) to the copolymer rubber (B) ((A)/( A polypropylene resin composition having excellent rigidity, impact resistance, moldability, etc., characterized in that B)) is about 50/50 to about 95/5. 2. The composition according to item 1, wherein the α-olefin is 1-butene. 3. The composition according to item 1 or 2, wherein the nonconjugated polyene is dicyclopentadiene or 5-ethylidene-2-norbornene.