JPH04314739A - Structure of thermoplastic polyolefin resin composition and preparation thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a structure in which a thermoplastic polyolefin resin is used as a matrix and a thermoplastic polyamide resin is dispersed in the matrix, and a method for manufacturing the same.
The present invention provides a resin molded product that can be formed by a simple method, maintains the excellent features of thermoplastic polyolefin resin as a molded product, and has particularly improved heat resistance, mechanical properties, etc.

0002

[Prior Art and Problems to be Solved by the Invention] Polyolefin resins represented by polyethylene and polypropylene are thermoplastic resins that are inexpensive, lightweight, and have excellent moldability and chemical resistance. Widely used as electronic components. However, polyolefin resins generally have low heat resistance (heat distortion temperature) and low mechanical properties, making them unsuitable for fields where heat resistance, mechanical strength, etc. are required. To solve these problems, alloying of polyolefin resins and various resins has been carried out, but for example, simply kneading thermoplastic polyamide resins results in poor dispersion, and the heat resistance, mechanical properties, etc. There was not much improvement compared to resin alone. Furthermore, if a compatibilization method such as modification with maleic anhydride was used for the purpose of improving dispersibility, the polyamide resin would be dispersed in the form of particles, and the expected thermal and mechanical properties could not be obtained. The present invention solves the drawbacks caused by poor dispersibility of both components when a thermoplastic polyamide resin is blended with a thermoplastic polyolefin resin, and improves the heat resistance, mechanical properties, etc. of the molded product. With the goal.

0003

[Means for Solving the Problems] In view of the above-mentioned problems, the present inventors have conducted extensive studies on improving the dispersion form of a polymer blend of a thermoplastic polyolefin resin and a thermoplastic polyamide resin. By using a dispersion improver in combination and adjusting the relative surface tension between each component during melt-kneading, a composition structure in which thermoplastic polyamide resin is dispersed in a network shape in thermoplastic polyolefin resin is formed. The inventors have discovered that the network structure obtained in this manner has further improved heat resistance and mechanical strength, leading to the present invention. That is, in the present invention, when thermoplastic polyolefin resin A is used as a matrix and thermoplastic polyamide resin B is melt-kneaded, the surface tension at the melt-kneading temperature is higher than that of component B, and the average particle diameter is 0.0.
A, characterized in that a filler C having a particle size of 5 to 50 μm and a specific modified polyolefin polymer D as a dispersibility improver are melt-kneaded in amounts that satisfy the following formulas (1) to (3). The present invention relates to a method for producing a composition structure in which components B interpenetrate and are dispersed in a network shape, and a molded article comprising the composition structure obtained by the production method. B/(A+B)=0.05-0.5 (weight ratio)
(1) C/(B+C)=0.1 to 0.7 (weight ratio) (2) D/(B+D)=0.02 to
0.5 (weight ratio) (3) First, to explain the dispersion form of the interpenetrating network structure referred to in the present invention, Fig. 1 is a schematic diagram showing the particle dispersion form in a conventional polymer blend system. The thermoplastic polyamide resin B, which has a relatively low content compared to a certain thermoplastic polyolefin resin A, has a dispersed form separated into particles. On the other hand, FIG. 2 is a schematic diagram showing the form of the interpenetrating network structure of the present invention, in which a specific filler C is included in the thermoplastic polyamide resin B,
Although the content of the thermoplastic polyamide resin B is small, the thermoplastic polyolefin resin A and the thermoplastic polyamide resin B mutually form a network and have an entangled structure to form a continuous phase. That is, in the present invention, at least a portion of the effective amount of the thermoplastic polyamide resin B relative to the thermoplastic polyolefin resin A generally exhibits a network structure in which the majority is substantially continuous with each other, and it is essential to exhibit such a dispersion form. The invention is characterized by the fact that it has achieved superior mechanical properties and heat resistance compared to the conventional particulate dispersion or layered dispersion form when a thermoplastic polyamide resin is simply blended with a thermoplastic polyolefin resin. be. Such a dispersed structure can be confirmed by appropriately crushing or cutting the formed structure, for example, a molded piece, and heating it with xylene to 120° C. to elute and remove component A, which is a matrix. When component B is dispersed in a network, it retains its shape even after matrix A is eluted and removed, whereas when it is separated and dispersed in granules or layers,
You can also see that the shape collapses and does not retain its original shape. In addition, by separating the matrix with an appropriate sieve after elution treatment, it is possible to almost quantitatively determine the portions existing in a network shape.

Next, the components used in the present invention will be explained. As is well known, the thermoplastic polyolefin resin of component A used in the present invention is one obtained by addition polymerizing an α-olefin hydrocarbon compound such as ethylene or propylene using an appropriate catalyst. You can also use it. Examples include polyolefin homopolymers such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, polypropylene, and polymethylpentene, and copolymers mainly composed of these. However, the copolymer preferably contains 20% by weight or less of comonomer components other than olefin. In addition, these components A may have a branched or crosslinked structure, and there are no particular restrictions on the degree of polymerization or degree of branching, and any material may be used as long as it has moldability.
It may be a mixture of more than one species.

Next, the thermoplastic polyamide resin of component B used in the present invention is, as is known, polycondensation of various diamines and dibasic acids, ring-opening polymerization of various cyclic amides, condensation polymerization of various ω-amino acids, etc. Both can be used. A typical example is nylon 66,
Examples include polyamide homopolymers such as nylon 6, copolymers mainly composed of these, and mixtures thereof. It may also be a copolymer, terpolymer, or block polymer containing a small amount of a soft segment or a modifying agent. Furthermore, there is no particular restriction on the degree of polymerization, and any polymer may be used as long as it has moldability.
If the viscosity of component B is significantly higher than that of component A during melt-kneading, it tends to be difficult to form the network-like dispersion shape that is the object of the present invention. (poise) is preferably 3 times or less, and especially when the amount of component B blended is relatively small, the lower one [e.g., the same or less when B/(A+B)<0.1] is preferable. desirable.

The blending ratio of components A and B in the present invention is such that component B accounts for 5 to 50% by weight, preferably 10 to 40% by weight of the total weight of components A and B. If the amount of component B is too small, it is difficult to form the network-like dispersed form that is the object of the present invention, and if it is too large, the inherent properties of the thermoplastic polyolefin resin will be lost, which is not preferable.

Next, component C needs to have a surface tension at least higher than that of component B at the same temperature, and preferably has a surface tension difference of 2 dyn/cm or more with component B. It is something.

The surface tension of each component is the surface tension at its melt-kneading temperature, and in the case of thermoplastic resins, it can be evaluated by the hanging drop method at that temperature, as is generally widely used. Here, the hanging drop method is a method of determining the surface tension of a liquid from the shape behavior of a droplet in which a tube is stood vertically, and a sample placed inside the tube becomes a droplet that hangs from the end of the tube. For those that do not melt (component C), the critical surface tension can be determined and evaluated using the contact angle method calculated by the Zisman plot method (see Examples below for details).

Regarding the relationship between the surface tensions of component A and component B, it is necessary that the surface tension of B, which is a minor component, is larger than that of A, which is a matrix component, at the melt-kneading temperature. The surface tension of polyamide resin B at the melt-kneading temperature is greater than that of thermoplastic polyolefin resin A, and this relative relationship is satisfied. Incidentally, the surface tension value of thermoplastic polyolefin resin A at 285°C is 10 to 20 dyn/cm (for example, polyethylene is about 17.5 dyn/cm, polypropylene is about 1
4.5 dyn/cm), and the value of thermoplastic polyamide resin B is about 25 to 40 dyn/cm (for example, nylon 66 is about 29.3 dyn/cm, nylon 6 is about 35 dyn/cm).
cm). Therefore, when kneading at 285° C., the surface tension of component C is at least higher than the value of component B, and preferably as high as possible.

The filler of component C is preferably in the form of powder (or fibers) with an average particle size (or average fiber length) of 0.05 to 50 μm, more preferably an average particle size of 0.05 to 50 μm.
．． It is 1 to 10 μm. The smaller the particle size, the more advantageous it is to form a fine network structure. The blending amount of component C is suitably 10 to 70% by weight, preferably 20 to 60% by weight, based on the total weight of components B and C. If the amount is too small, it will be difficult to exhibit the effects of the present invention, and if it is too large, the physical properties will be affected, which is undesirable. The filler for component C may be either an inorganic filler or an organic filler, as long as it satisfies the above conditions and has a surface tension value greater than that of component B at the melt-kneading temperature as described above. It may be of any shape, such as granule, powder, plate, etc., depending on the purpose. For example, inorganic fillers include glass fibers, asbestos fibers, silica fibers, silica/alumina fibers, alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, boron fibers, potassium titanate fibers, etc. with an average fiber length of 50 μm or less. Inorganic fibrous substances, carbon black, graphite, silica, quartz powder, glass beads, milled glass fiber,
Glass balloons, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, silicates such as wollastonite, metal oxides such as iron oxide, titanium oxide, zinc oxide, antimony trioxide, alumina,
Metal carbonates such as calcium carbonate and magnesium carbonate; metal sulfates such as calcium sulfate and barium sulfate;
Other ferrite, silicon carbide, silicon nitride, boron nitride, etc.
In addition, the average diameter of mica, glass flakes, etc. is 50 μm.
The following granular or plate-like fillers are selected as component C in consideration of the relative surface tension value with respect to component B used.

[0011] The organic filler C may be a heat-resistant, high-melting-point thermoplastic resin, as long as it satisfies the above conditions.
Fillers made of thermosetting resins can be used, examples of which include aromatic polyamide resins, aromatic polyimide resins, liquid crystal polymers, melamine resins, phenolic resins, epoxy resins, etc. It is effective as component C as long as it satisfies the conditions. These granular materials can be used alone or in combination of two or more. Moreover, these fillers can be effectively used as component C by subjecting them to surface treatment with a suitable surface treatment agent or the like to adjust the surface tension.

Next, component D as a dispersibility improver is a modified compound having one or more of various carboxylic acid groups, carboxylic acid anhydride groups, carboxylic acid metal bases, carboxylic acid ester groups, imino groups, amino groups, and epoxy groups. Polyolefin polymers such as maleic anhydride, succinic anhydride, itaconic anhydride, citraconic anhydride, N-phenylmaleimide, N-cyclohexylmaleimide, glycidyl acrylate, methacrylic acid alkyl ester and/or
Alternatively, examples include polyolefin copolymers or graft copolymers in which these derivatives are chemically introduced and bonded to polyolefins such as polypropylene, polyethylene, and ethylene-propylene copolymers, and modified polyolefin copolymers or graft copolymers, or polyamide graft-modified polyolefins made of polyolefins and polyamides. . Particularly preferable specific examples of component D include modified polyolefins such as maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, ethylene-propylene-maleic anhydride copolymer, succinic anhydride-modified polyethylene, and itaconic anhydride-modified polyethylene; These include polyamide graft-modified polyolefins. There are no particular restrictions on the degree of polymerization of component D, etc.
It may also be an oligomer that itself does not have moldability. The blending amount of component D is suitably 2 to 50% by weight, preferably 5 to 30% by weight, based on the total weight of components B and D. If it is too small, it will be difficult to achieve the effects of the present invention.

The presence of component D plays an important role in forming a dense network-like dispersion form in component A, in which component B is a matrix together with component C, and component D is not present. In some cases, even if component C is present, it is difficult to form a sufficiently uniform network phase structure, and conversely, if component D is present but component C is not present, component B will disperse as small particles but will not form a network phase structure. This does not result in a uniform dispersion form, and the effects of the present invention are not fully exhibited. The development of the network-like dispersion morphology of the present invention is achieved by the presence of component C that satisfies the above conditions during melt-kneading, so that filler component C is selectively included by component B under the influence of its relative surface tension. Furthermore, it is understood that component B, which is subdivided due to the presence of component D and at the same time contains a large number of components C, extends in the form of branches in conjunction with the movement and dispersion of component C by kneading, and joins to form a network structure.

[0014] When component A, which is the matrix, is a modified polyolefin polymer that has the structural requirements as a dispersion improver for component D, that is, when components A and D have the same requirements, Since Component A itself also functions as a dispersibility improver, the desired effects of the present invention can be sufficiently obtained even without adding Component D separately. Therefore, in such a case, it should be understood that component A contains component D even if another component D is not particularly added, and such a case is also included within the scope of the present invention. However, at this time, there is no problem even if another component D is blended.

[0015] The thermoplastic polyolefin resin composition structure of the present invention may further contain conventionally known additives such as lubricants, lubricants, nucleating agents, dyes and pigments in order to impart desired properties within a range that does not impair its purpose. , release agents, antioxidants, heat stabilizers, weathering (light) stabilizers, reinforcing agents, hydrolysis stabilizers, addition of thermoplastic resins other than components A, B, and D, fillers other than component C, etc. Agents may also be added.

The composition structure of the present invention can be prepared by various known methods, but at least four of A, B, C, and D can be used.
It is preferable to heat-melt and knead for 30 seconds or more in the presence of the components, and other components may be simultaneously blended or added separately. Specifically, for example, components A to D are mixed uniformly in advance in a tumbler or a kneader such as a Henschel mixer, and then fed into a single-screw or twin-screw extruder where they are melt-kneaded, made into pellets, and then molded. It may be provided or directly molded. Note that the melt-kneading mentioned here is desirably carried out at a shear rate of 40 sec-1 or more at the melting temperature. A particularly preferable shear rate is 100~
It is 500 sec-1. The treatment temperature is 5°C to 100°C higher than the melting temperature of the resin component, particularly preferably 10°C to 60°C higher than the melting point. If the temperature is too high, decomposition or abnormal reactions may occur, which is undesirable. Further, the melt-kneading treatment time is 30 seconds or more and 15 minutes or less, preferably 1 to 10 minutes.

[0017]

Effects of the Invention The thermoplastic polyolefin resin composition structure of the present invention has a structure in which a thermoplastic polyamide resin is dispersed in a thermoplastic polyolefin resin in a network shape, and can be formed by a simple method. It retains the characteristics of plastic polyolefin resin, and compared to the conventional particulate separation and dispersion of simply blending both components, the surface of the molded product does not exhibit a striped appearance and exhibits smooth and good surface characteristics. The mechanical strength, rigidity, elastic modulus, etc. are improved, and the heat resistance of molded products is also improved, so many applications are expected.

[0018]

[Examples] The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited thereto.

Examples 1 to 2 (A) Polypropylene resin (Hypol, manufactured by Mitsui Petrochemical Industries, Ltd.), (B) Nylon 66 (Polyplastics Co., Ltd.) having the surface tension values (285° C.) shown in Table 1. ) manufactured by Polyplastic Nylon 66), (C) Talc (manufactured by Fuji Talc Kogyo Co., Ltd., average particle size 2 μm or 20 μm), (
D) Maleic anhydride-modified polypropylene resin was mixed in the proportions shown in Table 1, and the inner diameter was 30 mm at a set temperature of 285°C.
Using a twin-screw extruder, the screw rotation speed was 100 rpm (
The mixture was melt-kneaded at a shear rate of about 125 sec-1) and pelletized. Next, test pieces were made from the pellets using an injection molding machine and evaluated. The results are shown in Table 1. still,
The method for measuring each characteristic value is as follows.

Surface tension measurement method (the following examples also follow this method) For polypropylene resin and nylon 66, an automatic surface tension meter PD-Z model manufactured by Kyowa Interface Science Co., Ltd. was used, and a hanging drop method (Maruzen) was used. New Experimental Science Course Volume 18 “Interfaces and Colloids”
(1977), pp. 78-79), 285
Measured in an atmosphere of ℃. Polypropylene resin is 14.5
dyn/cm, and nylon 66 was 29.3 dyn/cm. Regarding talc particles, the surface of talc raw stone was measured using the contact angle method (Maruzen Co., Ltd. New Experimental Science Course Vol. 18 "Interfaces and Colloids") using an automatic contact angle meter CA-Z manufactured by Kyowa Interface Science Co., Ltd. (1977), pp. 93-106), the critical surface tension was measured at each temperature, and the temperature coefficient was determined. The results are as follows, and the surface tension of talc at 285°C is 60 dyn/cm. 25℃ Surface tension 65dyn/cm60℃ Surface tension 65dyn/cm80℃ Surface tension 6
4dyn/cm temperature gradient (-dr/dT) = 0.02 Network structure confirmation method (the following examples also follow this) 10 x 1
A molded piece cut into a size of 0 x 3 mm was placed in a xylene solution, and heated on an oil bath at 120 °C for 5 hours to elute polyolefin resin A as a matrix resin and dispersion improver D, and then examined with the naked eye and with an optical microscope. The morphological changes were observed using an electron microscope, and the dispersion morphology of the thermoplastic polyamide resin, which did not change under these conditions, was investigated. Here, if the thermoplastic polyamide resin is dispersed in particles as in the past, it will not remain in the form of a molded piece and only deposits of particulate thermoplastic polyamide resin will be observed with the naked eye or with an optical microscope. . On the other hand, when the thermoplastic polyamide resin has a network structure as in the present invention, the molded piece retains its shape, which can be observed with the naked eye or with an optical microscope. Furthermore, when observed under magnification using a scanning electron microscope, the network structure can be seen more clearly. Incidentally, an electron micrograph showing the particle structure (network structure) of the composition structure of Example 1 after the elution treatment is shown in FIG. In addition, as a quantitative evaluation method for this network structure, after dissolving the matrix resin A using the method described above, it was separated using a 12-mesh sieve, and the remaining weight was examined. Although the particulate dispersed portion passes through the sieve and does not remain, the network structure portion remains, so the remaining weight % means the weight of (B+C) of the network structure portion. Tensile strength and elongation: Measured according to the method of ASTM D638. Heat distortion temperature: 1 according to ASTM D648 method
Measurement was performed with a load of 8.6 kg. Flexural modulus: Measured according to ASTM D790 method.

Comparative Examples 1 to 5 The same applies to thermoplastic polypropylene resin A alone, nylon 66B alone, a combination of components A and B that does not contain filler C, or component D is not included. It was evaluated using the following method. The evaluation results are also shown in Table 1.

Examples 3 to 6, Comparative Examples 6 to 7 Molded pieces were prepared and evaluated in the same manner as in Example 1, except that the amounts of components C and D were changed as shown in Table 2. The evaluation results are shown in Table 2.

Examples 7 to 8 Molded pieces were prepared and evaluated in the same manner as in Example 1, except that the amounts of components A, B, C, and D were changed as shown in Table 3. The evaluation results are shown in Table 3.

Example 9, Comparative Examples 8 to 9 Component C was changed to calcium carbonate (manufactured by Shiraishi Kogyo Co., Ltd., average particle size 1 μm), and for comparison, silicone rubber particles (
Manufactured by Toray Silicone Co., Ltd., R-925, average particle size 1μ
m) and acrylic rubber particles (manufactured by Mitsubishi Rayon Co., Ltd., W
A molded piece was prepared and evaluated in the same manner as in Example 1, except that the powder was changed to 529 (average particle size: 0.3 μm). The evaluation results are shown in Table 4.
Shown below.

Examples 10 to 11 Molded pieces were prepared in the same manner as in Example 1, except that component D was changed to maleic anhydride-modified ethylene-propylene copolymer or polyamide graft-modified polypropylene, and the blending amounts were changed as shown in Table 5. Created and evaluated. The evaluation results are shown in Table 5.

Examples 12-13, Comparative Examples 10-11 Molded pieces were prepared and evaluated in the same manner as in the previous example, except that component B was changed to nylon 6 (Aramin, manufactured by Toray Industries, Inc.) and the blending amounts were as shown in Table 6. The evaluation results are shown in Table 6.

Examples 14 to 17, Comparative Examples 12 to 15 Component A was high-density polyethylene (manufactured by Mitsui Petrochemical Industries, Ltd.).
HIZEX) and component D was changed to maleic anhydride-modified polyethylene, molded pieces were prepared and evaluated in the same manner as in the previous example. The evaluation results are shown in Table 7.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

[Table 4]

[0032]

[Table 5]

[0033]

[Table 6]

[0034]

[Table 7]

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the dispersion state of a structure based on a conventional polymer blend system.

FIG. 2 is a schematic diagram showing the dispersion state of the structure according to the present invention.

FIG. 3 is an electron micrograph showing the particle structure (network structure) of the composition structure of Example 1 after elution treatment.

Claims (6)

[Claims] 1. When thermoplastic polyolefin resin A is used as a matrix and thermoplastic polyamide resin B is melt-kneaded, the surface tension at the melt-kneading temperature is higher than that of component B, and the average particle diameter is 0.05 to 50 μm. The A and B components interpenetrate each other, which is characterized by melt-kneading a certain filler C and a modified polyolefin polymer D as a dispersibility improver in amounts that satisfy the following formulas (1) to (3). A method for producing a composition structure in which the composition is dispersed in a network shape. B/(A+B)=0.05-0.5 (weight ratio)
(1) C/(B+C)=0.1 to 0.7 (weight ratio) (2) D/(B+D)=0.02 to
0.5 (weight ratio) (3) [Claim 2]
2. The method for producing a composition structure according to claim 1, wherein the surface tension of component C at the melt-kneading temperature is 2 dyn/cm or more greater than that of component B. 3. The method for producing a composition structure according to claim 1, wherein component A is a polyolefin polymer or a copolymer consisting mainly of α-olefin and containing 20% by weight or less of other comonomer components. 4. Component B is nylon 66, nylon 6, and a thermoplastic polyamide copolymer mainly composed of these;
or a mixture thereof, the method for producing a composition structure according to any one of claims 1 to 3. 5. Component D is a carboxylic acid group, a carboxylic acid anhydride group, a carboxylic acid metal base, a carboxylic ester group,
The method for producing a composition structure according to any one of claims 1 to 4, which is a modified polyolefin polymer having one or more of imino groups, amino groups, and epoxy groups. 6. A molded article comprising a composition structure produced by the method according to any one of claims 1 to 5.