JPH0415242A - Production of propylene polymer composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which can give a molding excellent in the balance between impact strength and rigidity and surface properties such as mar resistance and appearance by mixing a crystalline propylene polymer with a specified rubber, a specified CaCO3, an unsaturated organic acid and a radical generator in a specified mixing ratio and melt-kneading the obtained mixture. CONSTITUTION:60-33wt.% crystalline propylene polymer is mixed with 3-10wt.% at least one rubber selected from the group consisting of an ethylene/propylene rubber, an ethylene/butene-1 rubber and a styrene/butadiene rubber, 37-60wt.% (the total of the former three is 100 pts.wt.) CaCO3 having a specific surface area of 18000cm<2>/g or above, a content of particles of a particle diameter of 5mum of below of 80wt.% or above, a content of particles of a particle diameter of 2mum or below of 45wt.% or above, a content of particles of a particle diamter of 1mum or below of 25wt.% or above and a mean particle diameter of 1.25mum or below, 0.01-0.5 pt.wt. unsaturated fatty acid (e.g. maleic anhydride) and 0.01-1.0 pt.wt. radical generator [e.g. 1,3-bis(tert.butylperoxyisopropyl)benzene], and the obtained mixture is melt-kneaded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Background of the Invention] [Industrial Field of Application] The present invention relates to calcium carbonate having a specific particle size distribution, a propylene polymer, a specific rubbery component, an unsaturated organic acid, and a radical generator. This article relates to a method for producing a resin composition that has advanced surface properties (scratch resistance and appearance) and a good balance of physical properties (impact resistance and rigidity balance) by blending and melt-kneading. be.

<Prior art> It has been widely practiced to improve various properties such as rigidity, impact resistance, flammability, dimensional stability, printability, paintability, and adhesiveness by blending inorganic fillers with thermoplastic resins. It is being said.

However, although improvement by such methods is effective in terms of the above properties, the impact strength level and scratch resistance are low, and the molded product is prone to silver streaks, flow marks, wrinkles, etc., and the weld appearance is poor. It also has the disadvantage of making things worse.

Therefore, various methods have been used to improve these drawbacks. For example, to improve impact strength, there is a method using precipitated calcium carbonate of a specific particle size (Tokuko Kokō 5
9-31538), a method of blending specific heavy calcium carbonate with specific polypropylene (Japanese Patent Publication No. 44-9
30), a method of adding a polymer having rubbery properties to an inorganic filler-filled ethylene-propylene copolymer (JP-A-54-156372, JP-A-54-15)
6464), a method for improving the compatibility between an inorganic filler and a resin (JP-A-48-97947, JP-A-48-9794),
34937) etc. have been proposed.

In addition, to improve scratch resistance, a method of blending a specific organometallic compound with an inorganic filler into polyolefin (
Japanese Patent Publication No. 54-43250) and a method of using glass fibers and mica in combination (Japanese Patent Publication No. 59-37015) have been proposed.

<Problems to be Solved by the Invention> Although these various improvement methods have shown some degree of effectiveness, it is still difficult to achieve a balance between impact strength and rigidity, a high level of scratch resistance, and surface characteristics such as appearance. The quality is still insufficient in the field of required industrial parts.

[Summary of the invention]

Summary The present invention aims to solve these drawbacks of the conventional techniques, and focuses on the particle size distribution of calcium carbonate and the influence on quality due to improved adhesion at the interface between calcium carbonate and propylene polymer. As a result of extensive research, we found that calcium carbonate with a specific particle size distribution, a propylene polymer resin, an unsaturated organic acid, and a radical generator were blended and melt-kneaded to create a molded product with excellent surface properties (
The present invention was completed based on the knowledge that a resin composition having good scratch resistance and appearance) and good physical properties (balance of impact resistance and rigidity) can be obtained.

That is, in the method for producing the propylene polymer composition of the present invention, components (a) to (c) shown below are blended in the following composition ratio based on the total amount of components (a) to (c), component(
d) and component (e), component (d) is 0.01 to 0 with respect to 100 parts by weight of the total amount of components (a) to (c).
．． 5 parts by weight and component (e) in a ratio of 0.01 to 1.0 parts by weight, and are melt-kneaded.

Component (a): 60 to 33% by weight of crystalline propylene polymer Component (b): Ethylene/propylene rubber, ethylene/
3 to 10% by weight of at least one rubber selected from butene-1 rubber and styrene-butadiene rubber Component (c): Specific surface area is 18. 000 ct/g or more, 80% by weight or more of particle diameters of 5IJm or less, 45% by weight or more of 2- or less, 25% by weight or more of 11J11 or less, and an average particle diameter of 1.25n or less
7 to 60% by weight (However, the above specific surface area means the value measured by the air permeation method, and the particle size means the value measured by the liquid phase sedimentation method.) Component (d): Unsaturated organic acid component (e): Radical Generator effect> The propylene polymer composition produced by the production method of the present invention contains calcium carbonate to a certain extent in the composition, and furthermore, the unsaturated organic acid is oxidized by the radical generator. By improving the adhesion between crystalline propylene polymer and calcium carbonate, we are able to improve the surface properties of molded products with higher hardness (scratch resistance and appearance) and good physical properties (balance of impact resistance and rigidity). It is possible to manufacture industrial parts such as excellent acoustic parts and home appliance parts.

[Detailed description of the invention]

(I) Production of composition (1) Constituent component (a) Crystalline propylene polymer component (component (a)) The crystalline propylene polymer used in the present invention is:
It may be a propylene homopolymer (polypropylene),
It is also a copolymer of propylene and other α-olefins (eg, ethylene, butene, pentene, hexene, heptene, etc.). Such propylene polymers generally have an isotactic index (II) of 40 or more, preferably 60 or more. II is 4
A value less than 0 is unsuitable due to insufficient rigidity, hardness, etc.

In addition, the MFR (JIS-7210, 2.16 kg load) of these propylene polymers is 0.01 to 150 g/
10 minutes, particularly preferably 1 to 100 g/10 minutes.

If the MFR is less than 0.01 g/10 minutes, the moldability and appearance will deteriorate, and if it exceeds 150 g/10 minutes, the impact resistance will be poor and unsuitable.

Among such crystalline propylene polymers, polypropylene, propylene-ethylene block or random copolymers are preferred. In the case of this propylene/ethylene copolymer, one having an ethylene content of 1 to 25% by weight is particularly preferred. Here, the ethylene content is determined by a conventional method using infrared spectrum analysis and NMR.

These polypropylene and propylene/ethylene copolymers are preferred because polypropylene has rigidity,
It can be mentioned that particularly good results are obtained in terms of scratch resistance, appearance, and weld strength, and particularly good results are obtained in terms of impact resistance, scratch resistance, and appearance in the case of propylene-ethylene copolymers. Among them, MFR is high when the ethylene content is 1 to 10% by weight.
A propylene/ethylene block copolymer having a weight ratio of 1 to 100 g/10 min is particularly suitable.

(b) Rubbery component (component (b)) The rubbery component used in the present invention is ethylene propylene rubber (hereinafter referred to as EPR), ethylene butene-1
rubber (hereinafter referred to as EBR), styrene-butadiene rubber (
At least one type selected from the following 5BR).

The properties of these rubber-like components are not particularly limited, but EPR is ethylene/propylene binary copolymer rubber (EPM) or ethylene/propylene/nonconjugated diene ternary copolymer rubber (EPDM), Propylene content (weight) of 25-60%, preferably 20-45%
, Mooney viscosity ML (100℃) is 15-120
．． 1+4 Preferably 20 to 90, and for EPDM, those with an iodine value of 20 or less are suitable.

In addition, as for EBR, the butene content (weight) is 20 to 40.
%, preferably 25-35%, Mooney viscosity ML
(100°C) is 15-120, preferably 1+4, preferably 20-90. Furthermore, as an SBR, J
Mooney viscosity ML based on Is-6300 (
(100°C) is preferably 15 to 80, and particularly preferably 20 to 60. At the same time, the bound styrene content (weight) is preferably from 15 to 6096%, particularly preferably from 20 to 50%. Two or more of these rubbery components may be used in combination.

Among these rubbery components, it is particularly preferable to use EPR.

(c) Calcium carbonate component (component (c)) The calcium carbonate used in the present invention has a specific surface area of 18.
000 cd/g or more and particle size 5IJj1 or less is 80% by weight or more, 2- or less is 45% by weight or more, IIJ
m or less is 25% by weight or more and the average particle diameter is 1.25- or less. More preferably, the specific surface area is 22,000
A value of 0cj/sr or more is preferable. Further, as for the preferred particle size or particle size distribution, the upper limit of the particle size is substantially 51a.
1 or less is 95% by weight or more, 2- or less is 65% by weight or more,
III! 1 or less accounts for 35 to 60% by weight.

Particle size 5- or less weighs 80 times! Less than 1%, 2ujl or less is 4
Less than 5% by weight, average particle size 1.251a! If the amount of calcium carbonate is less than that, the resin composition obtained by the production method of the present invention will have poor scratch resistance, which is not preferable. If the content of 1- or less is less than 35% by weight or more than 60% by weight, the impact strength, scratch resistance, and appearance of the composition will be poor, which is not preferred.

Here, the specific surface area is measured using a constant pressure aeration type specific surface measuring device, such as Shimabara Seisakusho powder specific surface area measuring device 5S-100, based on the so-called air permeation method, which is a conventional method.

Further, the particle size distribution is measured by an integrated weight distribution value by a light transmission method using a liquid phase sedimentation method. Examples of the measuring device include the CP type (for example, P-50) manufactured by Shimadzu Corporation and the SKN type (for example, 5KN-1000 type) manufactured by Seishin Corporation. (Although it is common for differences in measurement values to occur due to differences in equipment, the above values are particularly
Calcium carbonate having the following particle sizes tend to show lower distribution values (wt%) than those of the SKN type, and in the present invention, the CP type is more accurate. ) The calcium carbonate used in the present invention is characterized in that calcium bicarbonate is used without any particular surface treatment. -Surface treatment to improve numerical dispersion (silane coupling agent-based, higher fatty acid-based, fatty acid metal salt-based, organic titanate-based)
This improves the compatibility with the resin to some extent and improves the physical property balance (stiffness and impact resistance balance), but it is insufficient in terms of scratch resistance, smoke generation during processing, etc.

(d) Unsaturated organic acid component (component (d)) The unsaturated organic acids or their acid anhydrides used in the present invention include acrylic acid, methacrylic acid, maleic acid, itaconic acid, maleic anhydride, and itaconic anhydride. , citraconic acid, etc. Maleic anhydride and itaconic anhydride are particularly effective.

(e) Radical generator component (component (e)) Specifically, the radical generator used in the present invention includes dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5
-dimethyl-2,5-di(t-butylperoxy)hexyne-3,1,3-bis(t-butylperoxyisopropyl)benzene, 1,1-bis(t-butylperoxy) -3,3 , 5-trimethylcyclohexane, benzoyl peroxide, t-butyl peroxyisopropyl carbonate, t-butyl hydroperoxide, di-t-butyl peroxide, and azo compounds.

(f) Other components In the production method of the present invention, various additives and compounding agents, such as lubricants, colorants, stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, and flame retardants, are used as necessary. etc. may be blended within a range that does not significantly impair the effects of the present invention.

(2) Blending amount The propylene polymer composition obtained by the production method of the present invention is composed of the above-mentioned components (a) to (e), and the blending ratio of these components is the same as the above-mentioned composition. Among components (a) to (e), components (a) to (c) have a crystalline propylene polymer component amount of (a) and a rubbery component amount of (a).
b), and the amount of calcium carbonate is (c), then (a) +
(b) + (c) respectively (a); 60-33% by weight, preferably 48-35% by weight (b); 3-10% by weight, preferably 4-7% by weight
(c): 37 to 60% by weight, preferably 45 to 58% by weight; if component (a) is less than the above range, the rigidity and appearance will be poor; if it exceeds the above range, the scratch resistance will be poor.

If component (b) is less than the above range, scratch resistance and impact resistance will be poor, and if it exceeds the above range, rigidity will be insufficient and the appearance will deteriorate.

If component (c) is less than the above range, the rigidity will be insufficient, and if it exceeds the above range, impact resistance and scratch resistance will deteriorate.

The amount of component (d) and component (e) is 0.01 to 0.5 parts by weight based on 100 parts by weight of the total amount of components (a) to (c). , preferably 0
．． 01~0. 3 parts by weight, and component (e) is 0.01
~1.0 part by weight, preferably 0.03 to 0.5 part by weight.

If the amount of component (d) is less than the above range, the scratch resistance will not be sufficient, and if it exceeds the above range, the impact resistance will be poor.
The effect of scratch resistance is also reduced.

Furthermore, if the amount of component (e) blended is less than the above range, the effect of the radical generator will not be fully exhibited, and if it exceeds the above range, the impact resistance will be markedly reduced and the appearance of the molded product will tend to deteriorate. occurs.

(3) Mixing When mixing the above-mentioned raw materials in the above-mentioned ratio, there is no particular restriction on the mixing order of each of these components, and the above-mentioned components (a) to (e)
A method of simultaneously mixing 5 components, any 2 to 3 of them
Any method may be used, such as mixing the components in advance and then sequentially mixing the remaining components.

When mixing these, in the present invention, usually 200 to
It is important to melt-knead at a temperature of 260°C, preferably 230-250°C.

At this time, if necessary for controlling MFH, a radical generator can be supplied to the crosstalk machine within the above range.

Specific means for the melt mixing include a -screw or twin-screw extruder, a powerful screw mixer, a Banbury mixer,
Although any conventionally known mixer such as a kneader or roll can be used, it is especially optimal to use a powerful screw type mixer.

(II) Composition The propylene polymer composition produced as described above contains a specific calcium carbonate in the composition, and the unsaturated organic acid is converted into a crystalline propylene polymer by a radical generator. By improving the adhesion between calcium carbonate and calcium carbonate, it gives the molded product surface characteristics of higher hardness (resistance and appearance) and good physical properties (balance of impact resistance and rigidity).
Since a molded product with an excellent appearance without flow marks, sink marks, or silver streaks can be obtained, it can be used as industrial parts such as audio parts and home appliance parts.

[Example of practical experience]

The present invention will be explained in more detail by showing Examples and Comparative Examples below. The various measurement methods used here are as follows.

(1) Impact strength: Notched Izo impact strength (based on JIS-7110, measurement temperature 23°C) (2)
Rigidity: Three-point bending modulus (according to J Is-7203, measurement temperature 23°C) (3
) Scratch resistance, the pencil scratch tester shown in JIS-5401 was improved and a sapphire needle was set in the pencil setting part, and a load was applied to each of the sapphire needles from 10 to 50
sr was applied and the sample was passed over a 2×120×80 dragon sheet test piece at a speed of 15 cm/min, and the scars were visually judged as follows.

Visual Judgment Results Judgment: There are no noticeable scratches under a 10g load. There are no noticeable scratch marks at 10 points and 20g load. No noticeable scratches at 20 points and 30g load. There are no noticeable scratches at 30 points and a load of 40g. There are no noticeable scratch marks with 40 points and 50g load. 50 points Examples 1 to 11, Comparative Examples 1 to
11 The ingredients shown in Table 1 were mixed at a temperature of 15°C to 30°C at 11,000 ml using a Henschel mixer with a capacity of 75 liters.
After mixing for 5 minutes under RP conditions, melt-kneading was performed at a temperature of 220°C to 230°C using a twin-screw kneader manufactured by Kobe Steel Corporation.
Next, the mixture was pelletized using a 50 mm single screw extruder at 230°C to 250°C.

Next, a test piece was prepared from this pellet using an injection molding machine (Toshiba 1590), and its physical properties were evaluated. The results are shown in Table 1.

Claims (1)

[Scope of Claims] Components (a) to (c) shown below are blended in the following composition ratio based on the total amount of components (a) to (c), and component (d
) and component (e), the component (d) is 0.01 to 0.
A method for producing a propylene polymer composition, which comprises blending the propylene polymer composition in a proportion of 5 parts by weight and 0.01 to 1.0 parts by weight of component (e) and melt-kneading the mixture. Component (a): 60 to 33% by weight of crystalline propylene polymer Component (b): Ethylene/propylene rubber, ethylene/
3 to 10% by weight of at least one type of rubber selected from butene-1 rubber and styrene-butadiene rubber Component (c): specific surface area of 18,000 cm^2/g or more and particle size of 5 μm or less Calcium carbonate 37 having an average particle size of 80% by weight or more, 45% by weight or more of 2 μm or less, 25% by weight or more of 1 μm or less, and an average particle size of 1.25 μm or less
~60% by weight (However, the above specific surface area means the value measured by the air permeation method, and the particle size means the value measured by the liquid phase sedimentation method.) Component (d): Unsaturated organic acid component (e): Radical generation agent