JPS603417B2 - Talc-containing propylene resin composition - Google Patents

Description

Detailed Description of the Invention The present invention provides a high balance of physical properties (especially a balance between impact strength and rigidity) obtained by blending talc with a specific particle size distribution into a propylene-ethylene copolymer resin. The present invention also relates to a resin composition having good molded product surface properties (particularly surface resistance and silver streak prevention properties).

By blending inorganic fillers with thermoplastic resin, we improve its rigidity, heat resistance, combustibility, dimensional stability, flame retardance, printability, paintability,
Improving various properties such as adhesion is widely practiced. Although modification by this method is effective in terms of the above-mentioned properties, it has the disadvantages of low impact strength (particularly surface impact strength), low surface scratch resistance, and the tendency for silver streaks to occur in molded products. There is.

Regarding methods for improving impact strength, methods for improving impact strength include a method using precipitated calcium carbonate of a specific particle size (Japanese Patent Application No. 54-28277); How to match (
(Japanese Patent Publication No. 44-193), a method of adding a polymer having rubbery properties to an ethylene-propylene copolymer filled with an inorganic filler (Sho 53-64250, Japanese Patent Publication No. 53-64257), Method for improving compatibility with resins (JP-A-48-197947, JP-A-49-34)
No. 937), etc. have been proposed.

In addition, regarding the improvement of surface resistance, a method of blending a specific organometallic compound with an inorganic filler into polyolefin (Tokukan Sho 54-4325 Publication), a method of combining glass fiber and mica (Tokukan Sho 53) 1118055 specification)
, a method of using a specific talc and a specific calcium carbonate in combination (Patent Application Akihiro-28276), etc. has been proposed.
Although each of these has been shown to be effective to some extent, the field of industrial parts requires a high level of surface properties such as a physical property balance between surface impact strength and rigidity, surface image resistance, and silver streak prevention properties. The quality is still insufficient for use in.

On the other hand, among inorganic fillers, talc is widely used as a filler because it is easy to obtain, easy to handle, and has good dispersibility in resins. Improvement methods are proposed.

Among these proposals, a method for adjusting the particle size distribution of talc is noteworthy.

For example, a method using ultrafine-grained talc as a filler (Special Publication No. 53-92850 No. 54-39453)
, a method of blending talc with a particle size of less than 10 mm and an aspect ratio of 6 or more into a polyvinyl chloride resin (Japanese Patent Application Laid-Open No. 1987-1
07948 Publication), a method of blending talc with an average particle size of 0.5 to 10 degrees to polypropylene and a soft resin component (Hakama Seki Publication No. 55-34271).

However, in some of these proposals, it is difficult to manufacture such talc because the talc is only ultrafine particles, and the resin composition containing it is also prone to molding defects and has poor surface scratch resistance. It is also difficult to improve silver streak prevention properties. In some cases, there is no limit to the proportion of talc (less than 1 French), which causes disadvantages such as the occurrence of silver streaks, decreased fluidity (if there are too many fine grains), and decreased rigidity (if there are too many fine grains). No adjustment is made to prevent this. Furthermore, other products have drawbacks such as the addition of a soft resin component as a third component, which reduces the rigidity and makes it impossible to find a quality balance. The present invention solves these drawbacks of the prior art, and as a result of focusing on the particle size distribution of talc and its influence on the quality of the propylene polymer matrix, we have identified talc with a specific particle size distribution. By blending with the propylene copolymer resin of After seeing what could be obtained, we arrived at the present invention.

That is, the present invention provides a propylene-ethylene copolymer resin with an ethylene content of 1 to 3 weight % and a melt flow rate of 0.1 to 100 m/10 minutes, and a particle size of 95 weight % or less of 10 French or less, 5 French 85% by weight or more and 1 or less 15
This is a talc-containing propylene resin composition characterized in that talc having a specific surface area of 30,000/ta or more is blended in an amount of 5 to 5% by weight based on the total amount of the composition.

However, the particle size of the talc mentioned above means a value measured by a light transmission method using a liquid phase sedimentation method.

In addition to being excellent in the above-mentioned aspects, the composition of the present invention does not show flow marks on molded products, does not cause grain galling, and has good bending impact strength such as Izod impact, so it can be used at a high level. This makes it possible to apply the resin to the field of industrial parts such as home appliance parts and automobile parts, which require a balance of quality.

The reason why the present invention emphasizes surface impact strength will be described below. The impact strength of resins can be roughly divided into so-called bending impact strength (JIS-K
7110, K7111) and the so-called surface impact strength (JIS-K5400) of DuPont, Fallen Ball, Gardner, etc.
, K671 & ASTM-D3029, etc.).

There are various opinions regarding the correspondence between these values and the impact strength (practical impact strength) of molded products obtained by injection molding, extrusion molding, etc.

In other words, when discussing practical impact strength, it is often argued that there are a wide variety of stress loading conditions and that it should not necessarily be fixed at any one point. To summarize, at least in the case of olefin polymer compositions, practical impact strength often tends to correspond more closely to so-called surface impact strength. Therefore, when discussing impact strength to improve the balance of physical properties in practical use, it is of great significance and practical to take up the surface impact strength values of DuPont, Gardner, Fallen Ball, etc.

The talc used in the present invention has a particle size of 10 or less.
% or more and 51 or less is 85% by weight or more, and the particle size distribution is 15 to 45% by weight.

Among these, those having an upper limit of particle size of substantially 15 or less are preferable, and particularly preferably those having a particle size of substantially 15 or less,
The content is 90% by weight or more of 10 peaks or less, 80% by weight or more of 5 peaks or less, and 15 to 45% by weight of 1mm or less. 95% by weight is 10〃 or less, 85% by weight is 5A or less.
If the talc is less than
It has poor surface scratch resistance and is not preferred.

In addition, if the particle size is less than 15% by weight, the rigidity and surface scratch resistance of the composition will be poor, while if the particle size is more than 45% by weight, silver streaks will occur during molding of the composition. It is undesirable because it is easy to mix and has poor fluidity.

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, CP-50) manufactured by Shimadzu Corporation and the SKN type (for example, SKN-100 bile type) manufactured by Seishin Corporation. Although it is common for differences in measurement values to occur due to differences in equipment, the values for the CP type mentioned above are lower than those for the SKN type (wt%), especially for talc with a particle size of 51 or less. ), and in the present invention, the CP type is more appropriate.

The particle size distribution of the talc dispersed in the resin can be determined by boiling point extraction of this composition with an organic solvent (for example, by diluting and dissolving it in xylene for about 1 hour in 130 to 140 q○,
It can be determined by measuring the particle size distribution of talc taken out by passing it through a cylindrical furnace paper to separate talc and resin, or by firing the composition, or by measuring the particle size distribution using the method described above.

Such talc is produced, for example, by the following classification method.

That is, talc raw stone is crushed using equipment such as a tube mill type crusher, an impact type crusher, a micron mill type crusher, a centrifugal roller type Raymond mill, etc., and if fine crushing is required, a micron mill, a jet type crusher, Jet O.
Finely grind with a miser, micronizer, jet balberizer, etc. Next, these crushed talcs are classified once or multiple times using a device such as a cyclone, multilon, micron separator, microplex, cyclone air separator, ultra separator, jetclon, or clacyclon. , adjust its distribution.

Among these, good results are often obtained using devices such as micron mills, micron separators, and cyclones.

Among talcs whose particle size distribution has been adjusted to an appropriate size by such a method, those having a specific surface area of 30,000 or more can be applied to the present invention.

Particularly good is one with a diameter of 38,000 or more (the specific surface area is
Measured using a constant pressure aeration type specific surface area measuring device, such as Shimadzu's powder specific surface area measuring device SS-10 model). Also,
The average value of the aspect ratio, which indicates the ratio of either vertical or horizontal length and thickness of this talc, is preferably 3 or more, particularly 4.
The above is good.

Note that this talc may or may not be surface-treated.

Examples of surface treatments include silane coupling systems, higher fatty acid systems, fatty acid metal salt systems, unsaturated organic acids or their derivatives (maleic anhydride systems, acrylic acid systems, etc.), organic titanate systems, resin acid systems, etc. Mention may be made of chemical or physical surface treatment with treatment agents.

In addition to the effects of the present invention, surface treatment is effective in improving coating properties, adhesion properties, tapping properties, moldability, kneading properties, and the like.

On the other hand, the propylene-ethylene copolymer resin used in the present invention has an ethylene content of 1 to 3% by weight, preferably 2 to 3% by weight.
It is 25% by weight. If the ethylene content is less than 1% by weight, the composition containing talc will have poor surface impact strength, and if the ethylene content exceeds 3% by weight, the rigidity will be insufficient.

Since the surface impact strength of a steel with a large ethylene content is generally significantly improved, the desired result can be obtained by adjusting the ethylene content.

Here, the ethylene content is measured by a conventional method such as infrared spectrum analysis or NM. This propylene-ethylene copolymer resin needs to be resin-like, not rubber-like, and has a melt flow rate (MFR) of about 0.1 to 100 m/10 min, preferably 0.2 to 80 m/10 min. It is 10 minutes long.

If the MFR is less than 0.1 min/10 min, molding defects are likely to occur, resulting in poor appearance of the molded product. Also, 100 evenings/1
If the time exceeds 0 minutes, the surface impact strength is insufficient. MF here
R is JIS-K7210 (230oo, 2.16k9
(Load). Further, the isotactic index (0) of this propylene-ethylene copolymer resin is preferably 40 or more, particularly 60 or more, especially 90 or more.

Those with a D of less than 40 lack rigidity and hardness. Such propylene-ethylene copolymer resins are so-called propylene-ethylene block copolymers or propylene-ethylene random copolymers, and can be appropriately selected from commercially available products. However, if anything, a propylene-ethylene block copolymer is preferable.

In addition, this propylene-ethylene copolymer resin may contain other unsaturated monomers (for example, butene-1, hexene-1, octene-1,4-methylbenzene) in small amounts that do not significantly impair the effects of the present invention. Q-olefins such as ten-1; vinyl esters such as pinyl acetate; unsaturated organic acids such as (meth)acrylic acid (ester) and maleic anhydride, or derivatives thereof). type, random type, or block type).

The blending ratio of the above talc and propylene-ethylene copolymer resin is 5 to 5% by weight of talc based on the total amount of the composition;
Preferably, the amount is 10 to 4% by weight, with the remainder being propylene-ethylene copolymer resin.

If the talc content is less than 5% by weight, not only the balance of physical properties will deteriorate due to insufficient rigidity, but also sink marks and deformation of the molded product will become noticeable. On the other hand, if the amount exceeds 5% by weight, the balance of physical properties will deteriorate due to insufficient surface impact strength, and the molded product will be prone to insufficient resin filling, flow marks, etc., and the appearance of the molded product will also deteriorate. In addition to the above-mentioned talc and propylene-ethylene copolymer resin, the composition of the present invention may contain other third components as long as the effects of the present invention are not significantly impaired.

These third components include surface-treated or untreated inorganic or organic fillers other than talc (e.g. calcium carbonate (such as car-quality, light quality, and quality), mica, glass fiber, barium sulfate, poppy, acid Calcium, clay, magnesium carbonate, alumina, silica, iron oxide, calcium sulfate, glass beads, glass powder, white carbon, hollow glass bulb, poppy, sand, poppy, stone, carbon black, aluminum hydroxide, magnesium hydroxide ,
Zinc oxide, basic magnesium carbonate, asbestos, zeolite, white oxide, molybdenum, titanium oxide, silica, sericite, shirasu, graphite, calcium hydroxide, calcium sulfite, gypsum fiber, carbon fiber, synthetic silicate fiber ( PMF: Processed Mineral Fiber),
quartz powder, bentonite, metal whiskers, wood flour, sodium sulfate), rubber synthesis (e.g. ethylene-propylene copolymer rubber, styrene-butadiene rubber, styrene;
butadiene-styrene block copolymer, nitrile-butadiene rubber, etc.), thermoplastic resins other than the propylene-ethylene copolymer resin used in the present invention (e.g., high, medium or low density polyethylene, polypropylene, etc.) -Olefin monopolymer, propylene-butene-
1-block or random copolymers, copolymers of Q-olefins such as propylene-hexene-1 copolymers, ethylene monomonovinyl copolymers, and Q-olefins and beanyls such as maleic anhydride grafted polypropylene. Olefin polymer resins such as copolymers with monomers, and N.

resins other than olefin polymer resins such as polycarbonate, acrylonitrile-butadiene-styrene resin (A-Satoshi), polystyrene, polyvinyl chloride, polyphenylene oxide, etc.), antioxidants (phenol-based, sulfur-based, etc.), Lubricants, various organic and inorganic pigments, ultraviolet absorbers, antistatic agents, dispersants, steel damage inhibitors, neutralizing agents, blowing agents,
plasticizer, antifoaming agent, flame retardant, crosslinking agent, flow improver,
Examples include weld strength improvers and the like.

The addition of these various resins and auxiliary agents not only improves the physical property balance and surface characteristics of molded products (surface scratch resistance, gloss, weld appearance, silver streaks, flow marks, etc.), but also improves printability, paintability, adhesion, Plating properties, tapping properties, moldability,
It is effective in improving kneading properties, weld strength, durability, etc.

These third components can also be added in combination.
The addition of an inorganic filler as a third component not only contributes to the effects of the present invention, but is also effective in improving coating properties, adhesion properties, moldability, tapping properties, thickening properties, and the like. Similarly, the addition of maleic anhydride grafted polypropylene or acrylic acid grafted polypropylene is effective in improving the physical property balance, surface scratch resistance, and the like. The composition of the present invention can be produced using a conventional kneading machine such as a single-scale extruder, a two-bag extruder, a Banbury mixer, a roll, a Brabender plastograph, or a kneader.

Usually, the bran is mixed in an extruder, etc., and the pellet-shaped compound is dried and then subjected to processing. However, in special cases, the rice bran and propylene-ethylene copolymer resin are directly fed to various molding machines. It is also possible to mold the product while kneading it in a molding machine. In addition, talc is kneaded in advance to a high concentration to make a masterbatch.
It is also possible to perform blend compounding or molding while separately diluting it with a propylene-ethylene copolymer resin or a talc-containing propylene-ethylene copolymer resin. The method of molding the composition of the present invention is not particularly limited, but extrusion molding and various thermoforming methods are suitable for compositions with a relatively low MFR, and injection molding is suitable for compositions with a relatively high MFR.

That is, the effects of the present invention can be exerted on molded products regardless of the molding method used, such as extrusion molding, blow molding, injection molding, sheet molding, aged molding, rotary molding, and lamination molding. The composition of the present invention thus obtained has a high balance of physical properties (surface impact strength - stiffness) and good surface properties of molded products (surface resistance and damage resistance and silver streak deterrent properties). EXAMPLES The present invention will be explained in more detail with reference to Examples below, but these Examples do not limit the present invention.

The various measurement methods used here are as follows.

■ Surface impact strength (Dupont impact strength) 35 legs x 50 sides x
2. Using a willow sheet, using the device shown in JIS-K5400 6-1 blade 2, B method (reference test), the diameter of the dart and the curved part of the receiving plate was 1/2 inch. An experiment was conducted and the impact strength value was defined as the fall energy at 50% failure (measurement temperature 23 oo).

■ Rigidity (three-point bending modulus) Based on JIS-K7203 (measured temperature 23qo).

■ Surface scratch resistance A modified pencil scratch test device specified in JIS-K5401 was used to set a 100 yen coin in the pencil set part and apply a load of 2,500 yen to the uneven part of the coin for 3 minutes.
Test specimens of 5 pigs x 5 mosquitoes x 2 cages were rubbed on a coarsely grained sheet (average height of protrusions: 0.1 side, average protrusion area: 4 fences), and the marks were visually judged as follows: (Kokuyama Constant Temperature 23
oo).

Visual inspection results: No scratch marks are observed. Almost no grade 1 scratch marks are observed. Some grade 2 scratch marks are observed. Grade 3 scratch marks are observed.
4th class■ Before silver streak deterrence■
Visually observe the occurrence of silver streaks on the rough grained sheet used in Section 3.

Example 1 Chinese talc was first coarsely ground using a Raymond mill, and then finely ground using a micron mill.

This talc is classified with a micron separator, and then precision classified with a cyclone, so that the talc is substantially 15 or less.
Particle size distributions were obtained in which particles of 10 or less were each 989% by weight, 5 or less were 9492% by weight, and 1 or less were 26 and 17% by weight, respectively. Further, their specific surface areas were 47, 200, and 39,200 mm, respectively. 25% by weight of each of these talcs and MFR 6/1
0 minutes, propylene-ethylene flotu copolymer pellet with an ethylene content of 7% by weight (BC-4 manufactured by Mitsubishi Yuka Co., Ltd.) 75% by weight, Pengalar and Carpon Plaque 5 as pigments.
: 1 (1 part by weight based on 1 part by weight of the entire composition) for 2 minutes in a super mixer made by Kawada Seisakusho, and then granulated into bran using a PCM type twin-screw extruder made by Ikegai Tekko Co., Ltd. (230°C) to obtain a pellet-like compound.

Thereafter, specimens were molded (at 230°C) using a screw-in line injection molding machine manufactured by Meiki Seisakusho, and their DuPont impact strength, three-point bending modulus, surface resistance, and silver streak prevention properties were evaluated. . The results are shown in Table 1 (No. 1 and 2).

Comparative Example 1 The crushing and classification conditions in Example 1 were partially changed, and Table 1 (
No. Talc having a particle size distribution as shown in 3 to 7) was obtained.

These talcs and the propylene-ethylene chloride used in Example 1.

The copolymer and the pigment were mixed, kneaded, prepared, and evaluated in the same manner as in Example 1. The results are shown in Table 1.

The specific surface areas of these talcs are 40,800 and 3, respectively.
It was the evening of 7000, 36400, 33800, 22300.

Example 0 Example INo. 1 and Table 1 (No. 8 to 1)
1) Propylene-ethylene floc or random copolymer (both prototypes) with the MFR and ethylene amount shown in the table are mixed in the same manner as in Example 1 at the ratio shown in the same table.
Drilled, prepared and evaluated.

The results are shown in Table 1. All showed a good quality balance.
Comparative Example 0 The talc used in Example 0 and the propylene-ethylene block copolymer or polypropylene (both prototypes) with the MFR and ethylene amount shown in Table 1 (Nos. 12 to 16) were mixed in the proportions shown in the table. Mixing, kneading, preparation, and evaluation were performed in the same manner as in Example 1.

The results are shown in Table 1. Example Mountain Example INo. Using a Mitsubishi Natco 80 female XL type screw-in line injection molding machine, a pellet-like compound having the same composition as 1 was molded into instrument panels, consoles,
Width 30 x length 6, assuming large auto parts such as trim.
A model molded flat plate (with coarse grain) of 0 enemy x wall thickness 3 willow was molded.

The obtained molded flat plate showed practically sufficient surface impact strength, rigidity, and surface image resistance, and also showed no silver streaks, graining, flow marks, etc., and a good appearance such as gloss and weld appearance. The weld strength was also sufficient for practical use.

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Claims (1)

[Claims] 1. A propylene-ethylene copolymer resin having an ethylene content of 1 to 30% by weight and a melt flow rate of 0.1 to 100 g/10 minutes, with a particle size of 95% by weight or less of 10μ or less, and 85% by weight of 5μ or less. A talc-containing composition comprising 5 to 50% by weight of talc having a particle size distribution of 1μ or less and 15 to 45% by weight and a specific surface area of 30,000cm^2/g or more based on the total amount of the composition. Propylene resin composition. (However, the particle size of the talc mentioned above means the value measured by a light transmission method using a liquid phase sedimentation method.)