JPH04298552A - Production of propylene resin composition - Google Patents

Abstract

PURPOSE:To produce a molding material which is light in wt. and high in stiffness and heat resistance. CONSTITUTION:The title compsn. having a density of 0.950g/cm<3> or lower and an elastic modulus of 25,000kg/cm<2> or higher is produced by mixing a crystalline propylene polymer with an inorg. filler and a hollow glass balloon filler separately or simultaneously or by mixing a mixture of the polymer with a part of the inorg. filler with the rest thereof and the balloon filler separately or simultaneously in a wt. ratio of the inorg. filler to the balloon filler of 1/99-99/1 and in an amt. of the sum of both fillers of 5-100 pts.wt. based on 100 pts.wt. the resin. The inorg. filler is selected from the group consisting of talc, mica, glass fiber, and a nonmetallic inorg. whisker, and the balloon filler has a mean particle density of 0.2-0.8g/cm<3> and a mean compressive strength of 250kg/cm<2> or higher.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for producing a propylene resin composition that is lightweight and has excellent rigidity and heat resistance. It is suitable as

0002

BACKGROUND OF THE INVENTION Conventionally, propylene resin compositions have been widely used in the field of industrial parts including automobiles because of their excellent mechanical strength, workability, economic efficiency, etc. Among these industrial parts, in fields that require high rigidity and heat resistance, inorganic fillers such as talc and glass fiber are combined to provide higher performance, such as automobile parts, specifically trims and instruments. It is widely used in interior parts such as panels, exterior parts such as bumpers, and functional parts such as fan shrouds.

0003

[Problems to be Solved by the Invention] However, such propylene resin compositions have hitherto had the following problems. In other words, as mentioned above, conventional propylene-based resin compositions that maintain high rigidity and heat resistance are inorganic fillers whose raw materials, such as talc and glass fibers, have a significantly higher density than propylene-based polymers. , because it is contained in a large amount and made into a composite, the density of the composition itself becomes too high, especially when imparting a high degree of rigidity or heat resistance, and the molded product itself becomes too heavy. It had such problems.

0004

[Means for Solving the Problems] [Summary of the Invention] As a result of various studies to solve the above problems, the present inventors have developed a product obtained by manufacturing using specific ingredients and a specific kneading method. The inventors have now completed the present invention by discovering that the propylene resin composition obtained has a high degree of rigidity and heat resistance despite having an extremely low density. That is, the method for producing the propylene resin composition of the present invention includes the following component (a):
Alternatively, a blend of component (a) and at least part of component (b) is melt-kneaded, and then component (c) or (
A composition obtained by blending component c) and the remaining amount of component (b) individually or simultaneously and kneading and having a density of 0.950 g/cm3 or less and an elastic modulus of 25,000 kg/cm2 or more, The composition ratio is 1/99 of component (b) and component (c) to 100 parts by weight of component (a).
~99/1 and the total amount is 5 to 100 parts by weight. (a) The density of the propylene homopolymer portion is 0.9070
g/cm3 or more and the MFR of the entire polymer is 0.5~
200g/10min Crystalline propylene polymer (b) Talc with an average particle size of 0.8 to 15 μm, average particle size of 3 to 15
At least one filler selected from mica of 0 μm, glass fibers with an average diameter of 18 μm or less, and non-metallic inorganic whiskers with an average diameter of 2 μm or less and an average aspect ratio of 5 or more (c) ASTM-D2840 (using an air comparison pycnometer) ) has an average particle density of 0.2 to 0.8
g/cm3, hollow glass bulb with an average pressure resistance of 250 kg/cm2 or more according to ASTM-D3102 (using glycerol)

[Detailed Description of the Invention] [I] Production of propylene resin composition (1) Raw material component (a) Propylene polymer: Component (a) used in the method for producing the propylene resin composition of the present invention The propylene polymer of component (a) includes a homopolymer of propylene (polypropylene), a majority weight proportion of propylene, and a minor weight proportion of other α-olefins (e.g., ethylene, butene, pentene, hexene, heptene,
4-methylpentene, octene, etc.), vinyl esters (
(e.g., vinyl acetate), aromatic vinyl monomers (e.g., vinyl acetate), aromatic vinyl monomers (e.g.,
styrene), vinylsilane (e.g., vinyltrimethoxysilane, vinyltrimethylsilane), etc., and a propylene homopolymer portion. The density of the polymer is 0.9070 g/cm3 or more, preferably 0.9075 to 0.920 g/cm3, and the MFR of the entire polymer (230°C, 2.16 kg, JIS-
K7210) is 0.5 to 200 g/10 min. Among these, propylene homopolymers (polypropylene) and copolymers of propylene and ethylene are preferred, especially those with an MFR of 1 to 100 g.
/10 min block copolymers of propylene and ethylene are preferred. Here, if the density of the propylene homopolymer portion is less than the above range, the rigidity and heat resistance of the resin composition will be poor and it is unsuitable. Furthermore, those having an MFR less than the above range have poor moldability, and those exceeding the above range have poor impact strength and are therefore unsuitable.

Such propylene polymers are produced by slurry polymerization, gas phase polymerization or liquid phase bulk polymerization using highly stereoregular polymerization catalysts. As the highly stereoregular polymerization catalyst, for example, a combination catalyst of a solid catalyst component formed by contacting magnesium chloride with titanium tetrachloride, an organic acid halide, and an organosilicon compound and an organoaluminum compound is used. Furthermore, when a propylene polymer modified with an unsaturated organic acid or a derivative thereof or a mixture thereof is used as the propylene polymer, the rigidity, heat resistance, and impact strength of the resin composition can be further improved. Valid and desirable. In order to modify the propylene polymer with an unsaturated organic acid or a derivative thereof, for example, unsaturated organic acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid; maleic anhydride, itaconic anhydride, Anhydrides of unsaturated organic acids such as citraconic anhydride; esters of unsaturated organic acids such as methyl acrylate and monomethyl maleate; amides of unsaturated organic acids such as acrylamide and fumaric acid monoamide; itaconic acid imide, etc. The polymer is modified by adding an imide of an unsaturated organic acid or the like in an amount of 0.01 to 20 parts by weight, preferably 0.05 to 15 parts by weight, per 100 parts by weight of the propylene polymer and subjecting it to graft reaction conditions. Among these, it is preferable to use acrylic acid or maleic anhydride for modification. During modification, organic peroxides such as benzoyl peroxide and dicumyl peroxide are used to accelerate the degree of modification. This modification method is not particularly limited, but for example, a method of heating and melt-kneading at a temperature higher than the melting point of the propylene polymer or a method of reacting in a solution is adopted.

(b) Filler: Component (b) The above-mentioned filler used in the method for producing the propylene resin composition of the present invention
The filler of component b) has an average particle size of 0.8 to 15
μm, preferably 1-5 μm talc, average particle size 3-5 μm
At least one selected from mica having a diameter of 150 μm, preferably 5 to 120 μm, glass fibers having an average diameter of 18 μm or less, preferably 6 to 13 μm, and non-metallic inorganic whiskers having an average diameter of 2 μm or less and an average aspect ratio of 5 or more. It is. Talc is manufactured by, for example, pulverizing talc raw stone using an impact type crusher or a micron mill type crusher, further finely pulverizing it using a micron mill or jet type crusher, and then classifying it using a cyclone, a micron separator, or the like. If talc with an average particle size exceeding the above range is used, the impact strength and appearance of the molded product of the resin composition will be poor; if the average particle size is smaller than the above range, it will be difficult to disperse the talc, and the impact strength and appearance will deteriorate. Getting worse. Further, mica is produced in a similar manner to the above-mentioned talc, and any type of mica such as white mica, gold mica, black mica, etc. may be used. If mica having an average particle size exceeding the above range is used, the impact strength and appearance of the molded product of the resin composition will be poor, and if the average particle size is smaller than the above range, the rigidity and heat resistance will be poor, making each of these unsuitable. Furthermore, if the average diameter of the glass fiber exceeds the above range, the rigidity and heat resistance of the molded article of the resin composition will be poor, which is not preferable. The glass fiber has a final adhesion amount of surface sizing agent (sizing agent and surface treatment agent) of 0.10 to 0.3.
0% by weight is preferred. Whiskers whose average diameter and average aspect ratio exceed the above ranges are undesirable because the molded product of the resin composition will have poor rigidity, heat resistance, and appearance. These include, for example, aluminum borate whiskers, potassium titanate whiskers, and basic magnesium sulfate whiskers [magnesium oxysulfate whiskers MgSO4 .5Mg(OH)2 .3H2 O].
, titanium oxide whiskers, calcium carbonate whiskers, and the like. Preferable ones have an average diameter of 1.5 μm or less and an average aspect ratio of 10 or more, and particularly preferable ones have an average diameter of 1.0 μm or less and an average aspect ratio of 15 or more.

These fillers may be surface-treated with a surfactant, a coupling agent, or the like. Surface-treated fillers are effective in further improving the rigidity, heat resistance, impact strength, and appearance of molded articles of resin compositions. Particularly preferred are glass fibers, mica, and various whiskers surface-treated with a coupling agent such as a silane type. In addition, these (b) components may be dispersed in advance at a high concentration in various resins, for example, propylene polymers such as the above-mentioned (a) component (so-called masterbatch formation). It is also possible to use fibers containing the same length in a crystalline propylene polymer (so-called long fiber glass blended pellets). In this case, rigidity, heat resistance, and molding warpage can be improved. Here, the filler of component (b) is 1:99 to 1:99 by weight with component (c) detailed below.
The ratio is 99:1. Especially 10:90-9
The range of 0:10 is preferred, especially 20:80 to 80:2.
It is preferable to mix the amount within the range of 0. Here, in relation to component (c), if the component (b) is too small, rigidity tends to be insufficient, and if it is too large, it tends to be overloaded, which is not preferable.

(c) Hollow glass spheres: (c) The hollow glass spheres of the above component (c) used in the method for producing the propylene resin composition of the present invention have an average particle density of 0.2.
~0.8g/cm3, average compressive strength 250kg/c
m2 or more. Here, the average particle density is AS
The value was measured according to TM-D2840 (using an air comparison pycnometer), and the average compressive strength was the value measured according to ASTM-D3102 (using glycerol). The method for manufacturing the hollow glass spheres is not particularly limited, but those with an average particle density outside the above range are unsuitable because the density of the resin composition will be excessive and kneading will be difficult; If a material outside this range is used, it will be damaged during kneading and the density of the resin composition will become excessive, so it is inappropriate. Among these, those with an average particle density (true density) of 0.3 to 0.8 g/cm3 and an average compressive strength of 300 kg/cm2 or more are preferable, particularly those with an average particle density of 0.4 to 0.7 g/cm3. Moreover, it is preferable that the average compressive strength is 500 kg/cm2 or more. Although the dimensions of the hollow glass spheres are not particularly limited, they usually have an average particle diameter of 40 to 100 .mu.m, and their bulk density is usually 0.1 to 0.6 g/cm@3. These hollow glass spheres may be surface-treated with surfactants, coupling agents, etc., and hollow glass spheres that have been surface-treated in this way improve the rigidity, heat resistance, impact strength, and appearance of molded products of resin compositions. This can be further improved. In particular, surface treatment with a coupling agent such as silane is preferred. The total amount of these components (b) and (c) is 5 parts by weight per 100 parts by weight of component (a).
~100 parts by weight. If it is less than this range, the physical properties will be insufficient, while if it exceeds this range, the appearance will be poor and it will be uneconomical, which is not preferable.

(d) Other additional components: Component (d) In addition to often using pigments for coloring such resin compositions, in addition to the above-mentioned components, oxidized Various additives such as inhibitors, antistatic agents, flame retardants, and dispersants can also be added. Furthermore, various resins, various elastomers, various fillers, etc. other than the above-mentioned components (a) to (c) may be blended within a range that does not significantly impair the effects of the present invention. In particular, the nucleating agent described below is preferred among the other additional components.

[0011] Nucleating agents include aromatic phosphate metal salts, aromatic carboxylic acid metal salts, and sorbitol-based nucleating agents, specifically sodium bis(4-t-butylphenyl) phosphate;
Sodium-2,2'-methylene-bis-(4,6-di-
t-butyl-phenyl)phosphate; lithium-2
,2'-methylene-bis-(4,6-di-t-butylphenyl)phosphate;aluminum-mono-hydroxy-di-pt-butylbenzoate; sodium benzoate; 1,3,2,4- Di-benzylidene-sorbitol; 1,3,2,4-di-(p-methyl-benzylidene) sorbitol; 1,3,2,4-di-(p-ethyl-benzylidene) sorbitol; 1,3,2, 4-G-
(2'4'-di-methyl-benzylidene)sorbitol;1,3-p-chloro-benzylidene-2,4-p-methyl-benzylidene-sorbitol; 1,3,2,4-
Examples include di-(p-propyl-benzylidene) sorbitol. Among these, sodium bis(4-t-butylphenyl) phosphate; sodium-2,2'-
Methylene-bis-(4,6-di-t-butyl-phenyl)phosphate; Lithium-2,2'-methylene-bis-4,6-di-t-butylphenyl)phosphate; Aluminum-mono-hydroxy -di-pt-butylbenzoate; sodium benzoate is preferred, especially sodium-2,2'-methylene-bis-(4,6-di-
t-butyl-phenyl)phosphate; lithium-2
, 2'-methylene-bis-(4,6-di-t-butylphenyl)phosphate is preferred. These nucleating agents are extremely effective in further improving the rigidity and heat resistance of the resin composition. The elastomers described below are also preferred among the other additional components.

Elastomers Examples of elastomers include ethylene/propylene binary copolymer rubber (EPM), ethylene/propylene/nonconjugated diene ternary copolymer rubber (EPDM), and ethylene/butene-1
These include ethylene-based elastomers such as binary copolymer rubber and ethylene/propylene/butene ternary copolymer rubber, hydrogenated styrene/butadiene block copolymers, and hydrogenated styrene/isoprene block copolymers. Here, the hydrogenated styrene/butadiene block copolymer and the hydrogenated styrene/isoprene block copolymer are completely or partially hydrogenated, respectively.For example, styrene/ethylene/butylene/styrene block copolymer, styrene/isoprene block copolymer, It is described as an ethylene/propylene block copolymer. Among these elastomers, ethylene/propylene binary copolymer rubber (EPM), ethylene/propylene/nonconjugated diene ternary copolymer rubber (EPD)
M), styrene/ethylene/butylene/styrene block copolymers, and styrene/ethylene/propylene block copolymers are preferred, especially those with a propylene content of 20 to 55
Weight%, Mooney viscosity (ML1+4100℃) is 10~
100 ethylene propylene binary copolymer rubber (EPM
) or ethylene/propylene/nonconjugated diene ternary copolymer rubber (EPDM), a styrene copolymer having a hydrogenation rate of 95% or more and a styrene content of 5 to 50% by weight is preferred. These elastomers are extremely effective in improving the performance, particularly impact strength and dimensional stability, of the resin composition obtained by the method of the present invention. Here, the content of each other additional component is a value measured by a conventional method such as infrared spectroscopy or NMR method, and the crystallinity of these rubbers is 30% or less of the total. It is preferable. Note that the manufacturing method and shape of these other additional components are not particularly limited.

(2) Kneading A resin composition is obtained by blending the components (a) to (c) above and then kneading the mixture. The kneading is carried out using a conventional kneading machine such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a roll, a Brabender plastograph, or a kneader. In the above-mentioned kneading process, the mixing order is important in the method for producing a propylene resin composition of the present invention. Among the above components (a) to (c),
Component (a) alone or a mixture of component (a) and at least a portion of component (b) is melt-kneaded in advance, and then only component (c) or component (c) and the remaining amount of component (b) are mixed together. It is necessary to mix and knead them individually or simultaneously. Specifically, for example, using a twin-screw extruder, first feed only the component (a) from the front half of the extruder, heat and knead it thoroughly, and then
Components (b) and (c) are individually fed from the latter half of the extruder and kneaded to produce the product. In other words, component (c) is always component (a) or component (a) and at least a portion of (
It is necessary to feed and knead the components b) after they have been sufficiently heated, melted and kneaded. If the components are not mixed in such a mixing order, component (c) will be destroyed and the remarkable effects of the present invention will not be achieved. In other words, the hollow glass bulbs in the obtained propylene resin composition are destroyed and the resin component enters the hollow parts of the glass bulbs, so the density of the entire propylene resin composition increases and the density becomes 0. .95
It exceeds 0 g/cm3, and a molded article using the propylene resin composition has a large specific gravity and is heavy. Therefore, it is important to perform the kneading so as not to destroy the hollow glass spheres of component (c). Note that a part of component (a) may be fed from the rear half of the extruder as long as the effects of the present invention are not significantly impaired.

(3) Propylene-based resin composition The propylene-based resin composition obtained as described above is in a state in which the hollow glass spheres contained in the composition are hardly destroyed (
90% or more, preferably 95 to 100% remaining), so the density is 0.950g/cm3 or less, preferably 0.940g/cm3 or less, particularly preferably 0.930g/cm2 or less and has an elastic modulus of 25,000 kg/cm2 or more, preferably 26
,000kg/cm2 or more.

[II] Production of a molded article A molded article can be produced using such a propylene resin composition by a conventional molding method. That is, any molding method such as injection molding, compression molding, extrusion molding (sheet molding, blow molding), etc. may be used, but molding by injection molding is particularly preferred. The molded body is preferably molded for use in the industrial field, particularly as an automobile part. Specific examples include interior parts such as trims and instrument panels, exterior parts such as bumpers, and functional parts such as fan shrouds.

[0016]

[Examples] The present invention will be explained in more detail below with reference to Examples and Comparative Examples. The raw materials and physical properties evaluated here are as follows. (1) Raw materials (a) Component a-1: Density is 0.9081 g/cm3, MFR is 1
0g/10min propylene homopolymer a-2: Density of propylene homopolymer part is 0.9078
g/cm3, total MFR is 5 g/10 min, propylene/ethylene block copolymer a-3 with ethylene content of 4.9% by weight: Density of propylene homopolymer portion is 0.9077
Acrylic acid-modified propylene with an overall MFR of 30 g/10 min and an ethylene content of 5.3 wt%.
Ethylene block copolymer (modifier concentration 0.25% by weight)
) a-4: Density of propylene homopolymer part is 0.905
Propylene/ethylene block copolymer (b) component b-1: 9 g/cm3, an overall MFR of 8 g/10 min, and an ethylene content of 5.7 wt%: an average diameter of 0.5 μm and an average aspect ratio of 25. Basic magnesium sulfate whiskers [Magnesium oxysulfate whiskers MgSO4・5Mg (
OH)2 ・3H2 O] b-2: Glass fiber with an average diameter of 9 μm, a length of 3 mm, and a final adhesion amount of surface binding agent of 0.25% by weight (surface treated with aminosilane coupling agent) b- 3: White mica with an average diameter of 90 μm and an average aspect ratio of 55 b-4: Talc with an average diameter of 2 μm (using Chinese raw stone) b
-5: Heavy calcium carbonate (c
) Component c-1: Average particle density (true density) is 0.60 g/cm3
, hollow glass bulb c-2 with an average compressive strength of 700 kg/cm2: c-1 surface treated with gamma-aminopropyltrimethoxysilane c-3: average particle density (true density) of 0.23 g/cm3
, hollow glass bulb c-4 with average compressive strength of 35 kg/cm2: average particle density (true density) of 0.38 g/cm3
, hollow glass bulb with average pressure resistance of 210kg/cm2

(2) Evaluation method Density: JIS-K71 for compact specimens
Measured according to 12. Flexural modulus: JIS-K7203 for molded product test pieces
Measured according to. The measurement temperature is 23°C. Molding warpage: Injection molded sheet (120mm x 120m
(m x 1.8 mm) was placed on a surface plate, one piece was held down, and the (maximum) amount of warpage of the other piece was measured and classified as follows. Less than 1.0mm: Very good Less than 2.0mm: Good 2.0mm
Above: Poor Heat distortion temperature: Measured on a molded product test piece in accordance with JIS-K7207. Fiber stress is 4.6 kg/cm2. Izod impact strength [with cutting notch]: Measured on a molded product test piece in accordance with JIS-K7110. The measurement temperature is 23°C.

Examples 1 to 7 and Comparative Examples 1 to 6 (1) Mixing using a mixer The following components (a) (powder), (b) and (c) were blended in the proportions shown in Table 1, and Tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane and 2-(2'-
Hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole above (a) to (c)
0.07 parts by weight of each component and 1 part by weight of a carbon black gray pigment masterbatch are added to 100 parts by weight of the components (c) alone, or ( All components except component c) and all or part of component (b) were thoroughly mixed using a high-speed mixer.

(2) Mixing using an extruder Next, using a twin-screw extruder manufactured by Japan Steel Works, the above-mentioned high-speed mixer mixed components are fed from the front half at a temperature of 220°C, and while melt-kneading, the remaining components are mixed. [Component (c) only, or all or part of component (c) and component (b)]
was fed from the latter half in an amount corresponding to the ratio shown in Table 1, and kneaded and granulated (excluding Comparative Example 6).

(3) Evaluation The colored pellets thus obtained were submitted to a screw in-line injection molding machine to form a molding warpage evaluation sheet (120 m
m x 120 mm x 1.8 mm) and a test piece for physical property evaluation was molded at 230°C. The molding cycles in this case were a total of 50 seconds and 45 seconds, respectively. The evaluation results are shown in Table 2.

[0021]

[Table 1]

[0022]

[Table 2]

Example 8 In the same formulation as in Example 2, sodium-2,2'-methylene-bis-(4,6-di-t) was added to 100 parts by weight of components (a) to (c) in total. -butyl-phenyl) phosphate was added in an amount of 0.1 part by weight, and the mixture was kneaded and granulated in the same manner as in Example 2. The evaluation results of this resin composition were: density: 0.902 g/cm 3 , flexural modulus: 29,200 kg/cm 2 , heat distortion temperature: 142° C., and Izod impact strength: 7.9 kg·cm/cm 2 .

[0024]

Effects of the Invention The propylene resin composition obtained by the method of the present invention has a high degree of rigidity and high rigidity, although it has an extremely low density, unlike those obtained by conventional propylene resin composition production. Since it is a heat-resistant propylene-based resin composition, lightweight molded products with high rigidity and heat resistance can be easily obtained by conventional molding methods. It is useful as a material for reducing the weight of housings, etc.

Claims (1)

[Claims] Claim 1: The following component (a), or a blend of component (a) and at least a part of component (b), is melt-kneaded, and then component (c) or the remaining amount of component (c) is added to the mixture. (b) The components are blended individually or simultaneously and kneaded to give a density of 0.950 g/cm3 or less and an elastic modulus of 2.
5,000 kg/cm2 or more, the composition ratio is 1/99 to 99/1 of component (b) and component (c) to 100 parts by weight of component (a), and A method for producing a propylene resin composition, characterized in that the total amount is 5 to 100 parts by weight. (a) The density of the propylene homopolymer portion is 0.9070
g/cm3 or more and the MFR of the entire polymer is 0.5~
200g/10min Crystalline propylene polymer (b) Talc with an average particle size of 0.8 to 15 μm, average particle size of 3 to 15
At least one filler selected from mica of 0 μm, glass fibers with an average diameter of 18 μm or less, and non-metallic inorganic whiskers with an average diameter of 2 μm or less and an average aspect ratio of 5 or more (c) ASTM-D2840 (using an air comparison pycnometer) ) has an average particle density of 0.2 to 0.8
g/cm3, hollow glass bulb with an average pressure resistance of 250 kg/cm2 or more according to ASTM-D3102 (using glycerol)