JP2023177769A - filler dispersant - Google Patents

Abstract

To provide a filler dispersant which imparts excellent mechanical strength to a thermoplastic resin composition containing a filler, especially, a polyolefin resin composition.SOLUTION: A filler dispersant (K) contains modified polyolefin (X) containing the following polyolefin (A) and an unsaturated (poly) carboxylic acid (anhydride) (C) as constituent raw materials, wherein molecular weight distribution (Mw/Mn) of the modified polyolefin (X) is 4.8 to 6.8. Polyolefin (A): containing α-olefin having 3 to 8 carbon atoms as an essential constituent monomer, and having number average molecular weight of 18,000-50,000.SELECTED DRAWING: None

Description

FIELD OF THE INVENTION The present invention relates to filler dispersants.

Polyolefin resins have excellent moldability, rigidity, electrical insulation, etc., and are inexpensive, so they are widely used as films, fibers, and other molded products in various shapes. In addition, various modifiers are being developed for polyolefin resins, and modifiers containing low molecular weight polyolefins have been proposed for the purpose of improving pigment dispersibility and mechanical strength (for example, patented Reference 1).

Japanese Patent Application Publication No. 2015-117362

However, even with the above technique, the mechanical strength was not fully satisfactory. An object of the present invention is to provide a filler dispersant that imparts excellent mechanical strength to a thermoplastic resin composition containing a filler, particularly to a polyolefin resin composition.

The present inventors have made extensive studies to solve the above problems, and as a result, have arrived at the present invention. That is, the present invention contains a modified polyolefin (X) containing the following polyolefin (A) and an unsaturated (poly)carboxylic acid (anhydride) (C) as constituent raw materials, and the molecular weight of the modified polyolefin (X) is A filler dispersant (K) having a distribution (Mw/Mn) of 4.8 to 6.8.
Polyolefin (A): Contains an α-olefin having 3 to 8 carbon atoms as a constituent monomer, and has a number average molecular weight of 18,000 to 50,000;

The filler dispersant (K) of the present invention has the following effects.
(1) Provide excellent mechanical strength (flexural strength, impact strength, etc.) to molded articles of the thermoplastic resin composition (Z).

<Polyolefin (A)>
The polyolefin (A) in the present invention contains an α-olefin having 3 to 8 carbon atoms as a constituent monomer, and has a number average molecular weight of 18,000 to 50,000.

Note that hereinafter, "α-olefin having 3 to 8 carbon atoms" may be referred to as "α-olefin".
Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene.
Among the above α-olefins, propylene is preferred from the viewpoint of isotacticity, which will be described later.

The above polyolefin (A) may include other monomers in addition to α-olefin as constituent monomers. In that case, the weight of other monomers is preferably 20% by weight or less, more preferably 15% by weight or less, even more preferably 10% by weight, based on the weight of all monomers constituting the polyolefin (A). It is as follows. Furthermore, based on the weight of all monomers constituting the polyolefin (A), the weight of other monomers is preferably 0.5% by weight or more, more preferably 1.0% by weight or more.

Other monomers constituting the polyolefin (A) include, for example, ethylene, 2-butene, isobutene, α-olefin (1-decene , 1-dodecene, etc.), and C4-30 unsaturated monomers other than α-olefins (eg, vinyl acetate).
Among the other monomers mentioned above, ethylene is preferred. Among (A), preferred is a propylene/ethylene copolymer.

From the viewpoint of mechanical strength, the number average molecular weight (Mn) of the polyolefin (A) is preferably 18,000 to 50,000, more preferably 25,000 to 47,000, particularly preferably 30,000 to 45 ,000.

In the present invention, the number average molecular weight (Mn) and weight average molecular weight (Mw) can be measured by GPC (gel permeation chromatography).
The conditions for measuring Mn by GPC in the present invention are as follows.
・Equipment: High temperature gel permeation chromatography
[“Alliance GPCV2000”, manufactured by Waters Co., Ltd.]
・Detection device: Refractive index detector ・Solvent: Orthodichlorobenzene ・Reference material: Polystyrene ・Sample concentration: 3mg/ml
・Column stationary phase: PLgel 10 μm, MIXED-B 2 bottles in series
[Manufactured by Polymer Laboratories Co., Ltd.]
・Column temperature: 135℃

The number of double bonds per 1,000 carbon atoms of the polyolefin (A) [the number of carbon-carbon double bonds in the molecular terminal and/or molecular chain of the polyolefin (A)] is the modified polyolefin (X ) From the viewpoint of productivity and mechanical strength, the number is preferably 0.2 to 20, more preferably 0.5 to 18, and even more preferably 1.0 to 15.
Here, the number of double bonds can be determined from the ¹ H-NMR spectrum of polyolefin (A). That is, the peak in the spectrum is assigned, and the number of double bonds in the polyolefin (A) is determined from the integral value derived from the double bond at 4.5 to 6 ppm of the polyolefin (A) and the integral value derived from the polyolefin (A). The relative value of the number of carbon atoms in the polyolefin (A) is determined, and the number of double bonds in the molecular terminal and/or in the molecular chain per 1,000 carbon atoms in the polyolefin (A) is calculated. The number of double bonds in the Examples described below was determined according to this method.

Examples of the method for producing polyolefin (A) in the present invention include the following.
(1) A method of thermally degrading a high molecular weight (preferably Mn 60,000 to 800,000, more preferably Mn 80,000 to 250,000) polyolefin (A0).
(2) A method of polymerizing α-olefin in the presence of a polymerization catalyst.

Among the above (1) and (2), (1) is preferred from the viewpoint of productivity.

The thermal degradation method includes (1) heating the high molecular weight polyolefin (A0) in the absence of an organic peroxide, for example, at 280 to 450°C (preferably 290 to 330°C) for 0.5 to 100 hours; , and (2) a method of heating in the presence of an organic peroxide [for example, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane] at, for example, 180 to 300°C for 0.5 to 100 hours. etc. are included.
Among these, from an industrial standpoint and from the standpoint of productivity of the modified polyolefin (X), method (1) is preferred since it can easily yield a polyolefin with a larger number of double bonds at the molecular terminal and/or in the molecular chain.

In the polyolefin (A), the higher the thermal degradation temperature or the longer the thermal degradation time in the thermal degradation step, the more the number of double bonds per 1,000 carbon atoms tends to increase.
Furthermore, the smaller the Mn of the high molecular weight polyolefin (A0), the higher the thermal degradation temperature, or the longer the thermal degradation time, the smaller the Mn of the polyolefin (A) tends to be.
In addition, polyolefin (A) may be used alone or in combination of two or more.

<Unsaturated (poly)carboxylic acid (anhydride) (C)>
The unsaturated (poly)carboxylic acid (anhydride) (C) in the present invention is an unsaturated monocarboxylic acid, an unsaturated polycarboxylic acid, and/or an unsaturated polycarboxylic acid anhydride.
The above unsaturated (poly)carboxylic acid (anhydride) (C) is a monocarboxylic acid having 3 to 24 carbon atoms [sometimes abbreviated as C] having one polymerizable unsaturated group, a polymerizable unsaturated group It is preferable to use a C4 to 24 polycarboxylic acid having one molecule and/or a C4 to 24 polycarboxylic acid anhydride having one polymerizable unsaturated group.

Among the unsaturated (poly)carboxylic acids (anhydrides) (C), unsaturated monocarboxylic acids include aliphatic monocarboxylic acids (C3-24, such as acrylic acid, methacrylic acid, α-ethyl acrylic acid, croton acids, isocrotonic acid), alicyclic-containing monocarboxylic acids (C6-24, e.g. cyclohexenecarboxylic acid); unsaturated poly(2-3 or more) carboxylic acids or their acid anhydrides include unsaturated dicarboxylic acids or their Acid anhydrides [aliphatic dicarboxylic acids or their acid anhydrides (C4-24, e.g. maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and their acid anhydrides), alicyclic-containing dicarboxylic acids or their acids Anhydrides (C8-24, such as cyclohexenedicarboxylic acid, cycloheptenedicarboxylic acid, bicycloheptenedicarboxylic acid, methyltetrahydrophthalic acid, and acid anhydrides thereof), and the like. The unsaturated carboxylic acid (anhydride) (C) may be used alone or in combination of two or more.

Among the above (poly)unsaturated carboxylic acids (anhydrides) (C), from the viewpoint of reactivity with polyolefin (A) and mechanical strength, unsaturated dicarboxylic acid anhydrides are preferred, and maleic anhydride is more preferred. It is an acid.

<Modified polyolefin (X)>
The modified polyolefin (X) in the present invention uses the polyolefin (A) and an unsaturated (poly)carboxylic acid (anhydride) (C) as constituent raw materials. The modified polyolefin (X) is, for example, a reaction product of a polyolefin (A) and an unsaturated carboxylic acid (anhydride) (C).
In the above reaction, a radical initiator (f) (such as dicumyl peroxide) may be used.

The acid value (mgKOH/g) of the modified polyolefin (X) is preferably 3.0 to 30 mgKOH/g (only numerical values are shown below), more preferably 4.0 to 25, particularly preferably 5.0 to 10. It is. The acid value here is a value measured according to JIS K0070.
Moreover, the above acid value can be adjusted as appropriate by the amount of double bonds possessed by the polyolefin (A), the weight of the polyolefin (A), and the type and weight of the unsaturated carboxylic acid (anhydride) (C).

Mn (number average molecular weight) of the modified polyolefin (X) is preferably 18,000 to 50,000, more preferably 25,000 to 47,000, and particularly preferably 30,000 from the viewpoint of mechanical strength balance. ~45,000.

The molecular weight distribution (Mw/Mn) of the modified polyolefin (X) is 4.8 to 6.8, preferably 5.0 to 6.5 from the viewpoint of mechanical strength. Molecular weight distribution (Mw/Mn) is the value obtained by dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn).
Moreover, as a method for adjusting the molecular weight distribution (Mw/Mn), for example, the following method can be mentioned.
(1) When a high molecular weight polyolefin (A0) with a large molecular weight distribution (Mw/Mn) is used, the molecular weight distribution (Mw/Mn) of the modified polyolefin (X) tends to become large.
(2) The lower the temperature at which the high molecular weight polyolefin (A0) is thermally degraded, the larger the molecular weight distribution (Mw/Mn) of the modified polyolefin (X) tends to be.

<Filler dispersant (K)>
The filler dispersant (K) of the present invention contains the modified polyolefin (X).
The filler dispersant (K) may contain (N2) to (N10) among the additives (N) described below, if necessary. In that case, the weight of the modified polyolefin (X) based on the weight of the filler dispersant (K) is preferably 90 to 99.9% by weight.
The filler dispersant (K) of the present invention imparts excellent mechanical strength (flexural strength, impact strength) to molded articles of the thermoplastic resin composition (Z) described below.

<Thermoplastic resin composition (Z)>
The thermoplastic resin composition (Z) of the present invention contains the filler dispersant (K), a thermoplastic resin (Y), and a filler (N1).

Examples of the thermoplastic resin (Y) include those other than the above (X), such as polyolefin resins [polypropylene, low density polyethylene, high density polyethylene], polystyrene resins, polyester resins, and nylon resins.
Among the above thermoplastic resins (Y), polyolefin resins are preferred.

Mn of the thermoplastic resin (Y) is preferably 60,000 to 500,000, more preferably 70,000 to 400, from the viewpoint of mechanical strength of the molded product and compatibility with the filler dispersant (K). 000, more preferably 80,000 to 300,000.

Examples of the filler (N1) include organic fillers (eg, wood flour, cellulose, paper) and inorganic fillers (eg, calcium carbonate, talc, glass fiber, carbon fiber).
Among these fillers (N1), from the viewpoint of mechanical strength, inorganic fillers are preferred, and calcium carbonate is more preferred.

The weight ratio [(K)/(Y)] between the filler dispersant (K) and the thermoplastic resin (Y) is preferably 3/97 to 25/75, more preferably 6 from the viewpoint of mechanical strength. /94 to 20/80.
In addition, the weight ratio [(N1)/{(K)+(Y)}] of the filler (N1) to the total of the filler dispersant (K) and the thermoplastic resin (Y) is determined from the viewpoint of mechanical strength. , preferably 10/90 to 75/25, more preferably 25/75 to 60/40.

The thermoplastic resin composition (Z) of the present invention may further contain a colorant (N2), a matting agent (N3), an antistatic agent (N4), and a dispersant (N5) within a range that does not impede the effects of the present invention. ), flame retardant (N6), foaming agent (N7), antioxidant (N8), ultraviolet absorber (N9), and plasticizer (N10). ) can be included.

The usage amount of each additive (N) based on the total weight of the thermoplastic resin composition (Z) is, (N2) is, for example, 10% by weight or less, preferably 1 to 5% by weight; (N3) is, for example, 20% by weight or less, preferably 1 to 10% by weight; (N4), for example, 10% by weight or less, preferably 1 to 5% by weight; (N5), for example, 20% by weight or less, preferably 0 to 15% by weight , more preferably 0 to 10% by weight; (N6), for example, 15% by weight or less, preferably 3 to 10% by weight; (N7), for example, 1 to 20% by weight, preferably 5 to 15% by weight; (N8) is, for example, 3% by weight or less, preferably 0.01 to 1% by weight; (N9) is, for example, 3% by weight or less, preferably 0.01 to 1% by weight; (N10) is, for example, 20% by weight or less; % or less, preferably 5 to 15% by weight.

In addition, if the additives between (N2) and (N10) are the same and overlap, each additive should be used in an amount that produces the corresponding additive effect, regardless of its effect as other additives. The amount used shall be adjusted depending on the purpose of use, taking into consideration that the effects of other additives can also be obtained at the same time.

The method for producing the thermoplastic resin composition (Z) of the present invention includes:
(1) A method of preparing a resin composition by mixing the thermoplastic resin (Y), the total amount of the filler dispersant (K), the filler (N1), and if necessary (N) all at once (bulk method);
(2) A masterbatch resin composition is prepared by mixing a part of the thermoplastic resin (Y), the entire amount of the filler dispersant (K) and the filler (N1), and if necessary, part or all of the additive (N). One example is a method (masterbatch method) in which the resin composition is prepared once and then the remaining thermoplastic resin (Y) and, if necessary, the remaining additives (N) are added and mixed to form a resin composition.
From the viewpoint of mixing efficiency of the filler dispersant (K), method (2) is preferred.

<Molded product>
The molded article of the present invention is a molded article of the above thermoplastic resin composition (Z). That is, the molded article of the present invention is obtained by molding the above thermoplastic resin composition (Z).
Molding methods include injection molding, compression molding, calendar molding, slush molding, rotational molding, extrusion molding, blow molding, film molding (casting method, tenter method, inflation method, etc.), and depending on the purpose, single-layer It can be molded by any method including molding, multilayer molding, foam molding, or the like. Examples of the form of the molded product include plate-like, sheet-like, film, and fibers (including nonwoven fabrics, etc.).

The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto. Parts in the examples represent parts by weight. In the examples, the number average molecular weight (Mn), the weight average molecular weight (Mn), the amount of double bonds of the polyolefin, and the acid value were measured by the methods described above.

<Manufacture example 1>
In a reaction vessel, high molecular weight polyolefin (A0-1) [trade name "Sun Allomer PLA00A", manufactured by Sun Allomer, hereinafter the same. ] 100 parts, heated and melted with a mantle heater while bubbling nitrogen into the liquid phase, and thermally degraded at 310° C. for 1200 minutes while stirring to obtain polyolefin (A-1).
The Mn of polyolefin (A-1) was 40,000, and the number of double bonds at the molecular terminal and/or in the molecular chain was 2.5 per 1,000 carbon atoms.

<Production Examples 2 to 13>
Thermal degradation was performed in the same manner as in Production Example 1, except that the high molecular weight polyolefin (A0), temperature, and time were changed according to Table 1 to obtain each polyolefin (A). The results are shown in Table 1.

<Example 1>
A reaction vessel was charged with 100 parts of polyolefin (A-1), 3 parts of maleic anhydride (C-1), and 1 part of dicumyl peroxide (f-1), and the mixture was heated to 200°C under nitrogen aeration. Stirring was continued for 10 hours. Thereafter, unreacted maleic anhydride was distilled off under reduced pressure (1.5 kPa, the same applies hereinafter) to obtain a filler dispersant (K-1) containing the modified polyolefin (X-1).
The modified polyolefin (X-1) had an acid value of 7.8, an Mn of 40,000, and an Mw/Mn of 5.8.

<Examples 2 to 15, Comparative Example 1>
According to Table 2, the reaction was carried out in the same manner as in Example 1, except that the polyolefin (A), unsaturated (poly)carboxylic acid (anhydride) (C), and radical initiator (f) were changed, and each filler dispersant ( K) was obtained. The results are shown in Table 2.

<Examples 21 to 56, Comparative Example 21>
According to the compounding composition (parts) in Tables 3 and 4, each filler dispersant (K), thermoplastic resin (Y), and filler (N1) were mixed in a twin-screw extruder [trade name "KZW45TW", manufactured by Technovel Co., Ltd.]. Each thermoplastic resin composition (Z) was obtained by melt-kneading at 230° C. and 100 rpm.
Each thermoplastic resin composition (Z) was injection molded using an injection molding machine [trade name "PS40E5ASE", manufactured by Nissei Plastics Co., Ltd.] at a nozzle temperature of 230°C and a mold temperature of 50°C, and evaluated according to the evaluation method described below. . The results are shown in Tables 3 and 4.

(1) Bending strength The bending strength of the molded product of the composition (Z) of the example was measured in accordance with ASTM D790, and the improvement rate (%) was calculated using the following formula.
Improvement rate of bending strength (%) = (bending strength of example) x 100/(bending strength of comparison)
Comparative bending strength: In the formulation composition (parts) of each example, a comparative dispersant (ratio K-1) was used instead of the dispersant of the example, and the bending strength was measured in the same manner as in each example. did.
Next, the improvement rate (%) of the bending strength calculated above was evaluated using the following <evaluation criteria>.
<Evaluation criteria>
◎: More than 150% ○: More than 100%, 150% or less △: More than 75%, 100% or less ×: Less than 75%

(2) Izod impact strength The Izod impact strength of the molded product of the composition (Z) of the example was measured in accordance with JIS K7110, and the improvement rate (%) of the Izod impact strength was calculated using the following formula. was calculated.
Improvement rate of Izod impact strength (%) = (Izod impact strength of example) x 100/(Izod impact strength of comparison)
Comparative Izod impact strength: In the compounding composition (parts) of each example, a comparative dispersant (ratio K-1) was used instead of the dispersant of the example, and the Izod impact strength was obtained in the same manner as in each example. Impact strength was measured.
Next, the improvement rate (%) of the Izod impact strength calculated above was evaluated using the following <Evaluation Criteria>.
<Evaluation criteria>
◎: More than 150% ○: More than 100%, 150% or less △: More than 75%, 100% or less ×: Less than 75%

From the results in Tables 1 to 4, it can be seen that the filler dispersant (K) of the present invention provides superior mechanical strength to the molded article of the thermoplastic resin composition (Z) compared to the comparative one.

The filler dispersant (K) of the present invention has an excellent dispersion effect for various fillers, and thus imparts excellent mechanical strength (flexural strength, impact strength, etc.) to molded articles of the thermoplastic resin composition (Z). For this reason, it is extremely useful for various thermoplastic resin molded products.

Claims (7)

It contains a modified polyolefin (X) containing the following polyolefin (A) and an unsaturated (poly)carboxylic acid (anhydride) (C) as constituent raw materials, and the molecular weight distribution (Mw/Mn) of the modified polyolefin (X) is ) is 4.8 to 6.8.
Polyolefin (A): Contains an α-olefin having 3 to 8 carbon atoms as a constituent monomer, and has a number average molecular weight of 18,000 to 50,000; The filler dispersant according to claim 1, wherein the number of double bonds per 1000 carbon atoms of the polyolefin (A) is 0.2 to 20. The filler dispersant according to claim 1, wherein the modified polyolefin (X) has an acid value (mgKOH/g) of 3.0 to 50. A thermoplastic resin composition (Z) comprising the filler dispersant (K) according to claim 1, a thermoplastic resin (Y), and a filler (N1). The thermoplastic resin composition according to claim 4, wherein the weight ratio [(K)/(Y)] of the filler dispersant (K) and the thermoplastic resin (Y) is 5/95 to 25/75. The weight ratio of the filler (N1) to the total of the filler dispersant (K) and the thermoplastic resin (Y) [(N1)/{(K)+(Y)}] is 10/90 to 75/25. The thermoplastic resin composition according to claim 4. A molded article obtained by molding the thermoplastic resin composition (Z) according to any one of claims 4 to 6.