JPH07228795A - Surface-treatment of talc, surface-treated talc, and resin composition - Google Patents

Abstract

PURPOSE:To obtain a surface-treated talc having an excellent affinity even for a lowly polar resin and being useful for obtaining a resin composition improved in mechanical properties by coating powdery talc with a specified polymer. CONSTITUTION:Powdery talc is coated with a polymer obtained by polymerizing a (meth)acrylic ester, desirably at least one member selected from butyl acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, hexadecyl (meth)acrylate and hexyl methacrylate, in the presence of a polymerization initiator desirably selected between sulfurous acid and 2,2'-azobis-(isobutyroamidine) hydrochloride. It is desirable that the the powdery talc used has a mean particle diameter of 20-0.05mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment method for powdered talc, a talc surface-treated by the method, and a talc-reinforced resin composition containing the surface-treated talc, particularly a polypropylene resin composition. .

Since the surface-treated talc of the present invention has a good affinity with organic materials such as resins and oils, it can be used as a reinforcing and modifying agent for resins and also as a functional powder in the field of cosmetics and the like. It is a promising material. Further, the talc reinforced resin composition is used as a material for electric / electronic device parts, mechanical device parts, automobile parts and the like.

[0003]

2. Description of the Related Art Conventionally, powdered talc has been used as a reinforcing and modifying material for thermoplastic resins such as polypropylene. Polypropylene containing finely powdered talc obtained by crushing natural talc mineral to 0.1 to 20 μm. Are on the market. In this case, the talc may be used as it is after being crushed, or may be used after being surface-treated with an organic acid or the like in order to prevent the particles from aggregating.

In glass fiber reinforced polypropylene and the like, the glass fiber surface is treated with an aminosilane coupling agent or the like to improve the affinity with polypropylene, but the talc surface is poor in reactivity, The effect of surface treatment with an aminosilane coupling agent or the like is not remarkably exhibited.

If a method for improving the affinity with resins such as polypropylene by surface-treating the surface of powdered talc with an effective means can be developed, mechanical properties such as tensile strength, elastic modulus and impact strength of talc reinforced resin can be developed. It can be expected that it can be further improved, and that the field of use can be expanded and the weight of products can be reduced.

On the other hand, inorganic powder materials such as various metal oxides and metal sulfides are dispersed in water and treated in the presence of methyl acrylate or methyl methacrylate to encapsulate the surface of the inorganic powder material with a polymer. A method has been proposed [Polymer, 34 (2), 90 (1985)]. However, this method is not applicable to all inorganic powder materials,
There is no example applied to powdered talc.

[0007]

DISCLOSURE OF THE INVENTION The present invention is to solve the above problems, and an object of the present invention is to coat powdered talc with a polymer of acrylic acid ester or methacrylic acid ester to encapsulate powdery talc. The object of the present invention is to provide a surface treatment method for talc and a surface treatment talc having a good affinity for an organic material having a small polarity. Another object of the present invention is to provide a resin composition having improved affinity between resin and talc and further improved mechanical properties such as tensile strength, elastic modulus and impact strength.

[0008]

Means for Solving the Problems The inventors of the present invention have made extensive studies as to the surface treatment method of talc, and as a result, by treating the surface of talc with an acrylic ester or a methacrylic ester under specific conditions, It has been found that talc-like talc is obtained by encapsulating talc with these polymers. Further, the obtained encapsulated talc has a good affinity with polypropylene, and the talc-reinforced polypropylene using the encapsulated talc of the present invention has mechanical properties higher than those using conventional untreated talc. The present invention has been found to be improved, and the present invention has been achieved.

That is, in the present invention, powdered talc, preferably having an average particle size of 20 to 0.05 μm, is used as an acrylic acid ester or a methacrylic acid ester, preferably butyl acrylate, decyl acrylate, dodecyl acrylate, Hexadecyl acrylate, hexyl methacrylate,
The polymer is coated with a polymer of at least one selected from decyl methacrylate, dodecyl methacrylate, and hexadecyl methacrylate. In the preparation of the polymer, preferably sulfurous acid or 2,2′-azobis (iso Butyroamidine) hydrochloride, a surface treatment method of talc comprising using a polymerization initiator selected from the above, a surface-treated talc obtained by the surface treatment method of talc and 100 parts by weight of a resin, particularly preferably 100 parts by weight of polypropylene. Part coated with a polymer of the above acrylic ester or methacrylic ester 1
It is a resin composition containing about 250 parts by weight.

As the acrylic acid ester or methacrylic acid ester used for encapsulating the powdery talc in the present invention, various ones can be used, but they are used with an aliphatic alcohol such as methyl acrylate or methyl methacrylate. Esters are preferable, and in particular, butyl acrylate, decyl acrylate, dodecyl acrylate, hexadecyl acrylate, butyl methacrylate, hexyl methacrylate, decyl methacrylate, dodecyl methacrylate,
Hexadecyl methacrylate and the like, in which the carbon chain of the alkoxy group is relatively long, for example, those having 3 or more carbon atoms, are preferable because the surface-treated talc having a good affinity with the organic material or the like when blended with the organic material or the like is obtained.

In the so-called encapsulation reaction in which powdery talc is coated with a polymer of acrylic acid ester or methacrylic acid ester, first, powdery talc is dispersed in water, and the ester and polymerization initiator are mixed with stirring. It is possible to proceed by adding and continuing stirring. In this case, the ratio of powdered talc and water may be appropriately selected within the range of 0.5 / 1 to 1/10. Further, as a polymerization initiator, sulfite, 2,2′-azobis (isobutyroamidine) hydrochloride (AIBA), sodium hydrogen sulfite, persulfate, which is generally used for the polymerization of acrylic acid ester or methacrylic acid ester, is used. Potassium, 2,2-azobis (isobutyronitrile) and the like can be used as appropriate, but sulfurous acid and AIBA are particularly preferable. The concentration of the polymerization initiator depends on the type of acrylic acid ester or methacrylic acid ester, but may be appropriately selected within the range of 1 to 10% with respect to the ester. The reaction temperature can be from room temperature to 100 ° C, which is the boiling temperature,
From the viewpoint of operability and reactivity, the range of 50 to 70 ° C is preferable. The optimum reaction time is affected by the concentration of the polymerization initiator and the reaction temperature, but 30 minutes to 5 hours is sufficient.

In the encapsulation reaction of powdery talc,
By controlling the reaction conditions, the polymerization amount of the organic monomer (encapsulation amount: weight ratio to talc) can be arbitrarily changed. When blended in the resin composition,
This encapsulation amount is preferably 0.1 to 50 wt%. When it is 50% or more, the encapsulated talc tends to aggregate, which is not preferable in handling.

By blending the encapsulated talc with a thermoplastic resin obtained by polymerizing an olefin or the like, particularly polypropylene, tensile strength, flexural modulus, Izod impact strength and the like can be improved and the physical property balance can be improved. An excellent talc-reinforced resin composition of is obtained.

The amount of encapsulated talc can be freely compounded up to about 70 wt% as in the case of conventional talc-reinforced polypropylene, but 100 parts by weight of resin encapsulates talc 1.
It is preferable to appropriately select and mix it in the range of up to 250 parts by weight. In this case, the encapsulated talc is easier to mix than untreated talc and the like. Further, compared to conventional products such as untreated talc, the effect of improving the physical properties is great, and therefore the amount of encapsulated talc can be reduced in order to obtain the same physical properties as conventional talc reinforced polypropylene. A generally used single-screw kneading extruder, a twin-screw kneading extruder, or the like can be used for compounding and kneading the encapsulated talc with polypropylene.

[0015]

【Example】

(Example 1) While flowing nitrogen gas into a 1 liter reactor equipped with a stirrer, 350 ml of distilled water and 100 g of talc (MS-P manufactured by Nippon Talc) having an average particle size of 10 μm were charged and stirred (500 rpm). After the temperature was raised to 65 ° C., 3 g of butyl acrylate (AB) was added, 0.15 g of sulfurous acid was subsequently added as a polymerization initiator, and stirring was continued for 1 hour in a nitrogen gas atmosphere. After completion of the reaction, the mixture was cooled to room temperature, filtered, washed with acetone and dried under reduced pressure to obtain encapsulated talc. The encapsulation amount was determined from the weight change of the obtained encapsulated talc and the raw material talc. The results of encapsulation are shown in Table 1.

(Examples 2 to 8) Decyl acrylate (A
D), hexadecyl acrylate (AHD), butyl methacrylate (MB), hexyl methacrylate (MH), decyl methacrylate (MD), hexadecyl methacrylate (MHD) except for the reaction conditions shown in Table 1. The talc was encapsulated in the same manner as in Example 1. The results of encapsulation are also shown in Table 1.

[0017]

[Table 1]

(Example 9) Using the same talc as in Example 1, 3 kg of encapsulated talc (encapsulation amount: 2.4 wt%) encapsulated with butyl acrylate (AB) and polypropylene (Nippon Mineralized Product 4800JG) ) After pre-mixing 7 kg with a super mixer (Kawata, SM-V-20 type), a continuous kneader (KCK, 70-22V)
(EX type) was kneaded and extruded into pellets to obtain encapsulated talc-reinforced polypropylene. The obtained talc-reinforced polypropylene pellets were injection-molded into a test piece by an injection molding machine (Yamashiro Seiki Seisakusho, SVA-60-52 type). Physical properties (tensile yield strength, tensile elongation, flexural modulus, Izod impact strength) were measured using a test piece obtained by injection molding. The tensile properties were measured according to JIS K6758, the flexural modulus was measured according to JIS K7203, and the Izod impact strength was measured according to JIS K7110. The results are shown in Table 2.

(Comparative Example 1) Untreated talc and polypropylene which were the same as in Example 1 were treated in the same manner as in Example 9 to obtain talc reinforced polypropylene and test pieces. Using the obtained test piece, the tensile yield strength, tensile elongation, flexural modulus and Izod impact strength were measured, and the results are shown in Table 2.

[0020]

[Table 2]

(Examples 10 to 15) Decyl acrylate (AD), hexadecyl acrylate (AHD), butyl methacrylate (MB), decyl methacrylate (MD),
Hexadecyl methacrylate (MHD) and methyl methacrylate (MM) were used to prepare encapsulated talc, and as in Example 9, encapsulated talc reinforced polypropylene (compounding amount of encapsulated talc: 30 wt%) and test pieces. Got Tensile yield strength and tensile elongation were measured using the obtained test pieces, and the results are shown in Table 3.

Example 16 Butyl methacrylate (M
Using B), encapsulated talc was prepared in the same manner as in Example 9 to obtain an encapsulated talc reinforced polypropylene (compounding amount of encapsulated talc: 60 wt%) and a test piece. Tensile yield strength and tensile elongation were measured using the obtained test pieces, and the results are shown in Table 3.

Comparative Example 2 Using untreated talc and polypropylene, talc reinforced polypropylene (talc compounding amount: 60 wt%) and a test piece were obtained in the same manner as in Example 9. Tensile yield strength and tensile elongation were measured using the obtained test pieces, and the results are shown in Table 3.

[0024]

[Table 3]

[0025]

The encapsulated talc (surface-treated talc) obtained by encapsulating powdery talc with a polymer of a specific acrylic acid ester and methacrylic acid ester is not treated by blending it with a thermoplastic resin such as polyolefin. Compared with the case of using talc, talc reinforced polypropylene with improved tensile yield strength, flexural modulus, Izod impact strength or balance of physical properties can be obtained.As a result, in order to obtain the same physical properties as conventional ones, the compounding The amount can be reduced, the weight of the product can be reduced, and it can be used as a reinforcing and modifying material. Further, the encapsulated talc of the present invention naturally has a high affinity with organic solvents and fats and oils, and therefore can be used as a functional powder in the field of cosmetics and the like.

Claims (7)

[Claims] 1. A method for surface treatment of talc, which comprises coating powdery talc with a polymer of acrylic acid ester or methacrylic acid ester. 2. The acrylic acid ester or methacrylic acid ester according to claim 1, which is butyl acrylate, decyl acrylate, dodecyl acrylate, hexadecyl acrylate, hexyl methacrylate, decyl methacrylate, dodecyl methacrylate, hexadecyl methacrylate. A surface treatment method for talc, which comprises using at least one selected from the group consisting of: 3. A surface treatment method for talc, wherein the powdery talc according to claim 1 has an average particle size of 20 to 0.05 μm. 4. The talc characterized in that the polymer according to claim 1 is polymerized with a polymerization initiator selected from sulfurous acid or 2,2′-azobis (isobutyroamidine) hydrochloride. Surface treatment method. 5. A surface-treated talc obtained by the method for surface-treating talc according to claim 1. 6. A resin composition comprising 100 parts by weight of a resin and 1 to 250 parts by weight of talc coated with a polymer of an acrylic acid ester or a methacrylic acid ester. 7. A resin composition, wherein the resin according to claim 6 is polypropylene.