JPS6361053A - Small, thin leaf metal-resin composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition suitable as gears, etc., having improved mechanical properties dimensional accuracy, tensile strength, etc., consisting of a specific small, thin metal subjected to surface treatment with a reaction product of an epoxy group-containing compound and a silyl isocyanate and an organic resin. CONSTITUTION:An organic resin (e.g. polyethylene, etc.) is incorporated with 1-90wt% small, thin metal (e.g. Cu, Ni, etc.) having 1-40mum maximum and 20-100 aspect ratio subjected to surface treatment with a reaction product of a compound (e.g. glycidyl acrylate, etc.) containing an epoxy group shown by formula II (n is 0-3; R is alkyl, etc.).

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a metal-resin composition in the form of small flakes that has high dimensional accuracy and excellent mechanical strength such as tensile and bending during injection molding.

<Prior art and its problems> In recent years, in order to improve the properties of organic resins, composite materials have been developed that are made by kneading various fillers such as glass fiber, metal powder, metal fibers, small flakes of metal (i.e., metal flakes), etc. compound is used.

However, in a molded product made by injection molding a compound kneaded with a fibrous filler, the fibrous filler is oriented in the compound, so the molded product has a gate direction (resin flow direction) and a direction perpendicular to the gate (resin flow direction). There are problems such as the size and shape particle size are reduced due to the difference in size from the direction (direction).

In addition, in compounds kneaded with metallic fillers, there is a problem that the mechanical properties of the compounds deteriorate due to poor adhesion between the metallic fillers and the punching machine resin, making them unsuitable for practical use.

For example, for the purpose of electromagnetic shielding,
-87142 publication describes Fe as a metal filler,
A compound in which flakes of Cu, Zn, Ni, and their alloys are added to a polyolefin resin, and JP-A-58-79050 discloses a compound in which A2 flakes and polyphenylene ether styrene resin are kneaded. . However, when the purpose is electromagnetic shielding, it is necessary to contain 20 to 60 voj 2% of metal filler, so metal fillers, especially metal flakes, that are blended with organic resin without surface treatment. The mechanical properties, which are the original characteristics of the resin, are significantly degraded, and even if electromagnetic shielding properties are obtained, there are extremely problems in terms of practical use.

For this reason, conventionally, when using metal fillers, especially metal flakes, it has been common practice to treat the surface of the metal flakes with a titanium-based or silane-based coupling agent in order to improve adhesion with organic resins. Are known. For example, as a surface treatment method for metal flakes, Japanese Patent Application Laid-Open No. 1604/1984 describes a method for treating the surface of metal flakes by using Nj, Cu, All,
A method of treating flakes such as Car, Sn, Ag, Au and stainless steel with organometallic titanates is disclosed. In addition, JP-A-59-223735 discloses that alloy flakes of All, Fe, Gu, Ni, and Sowara are treated with a silane coupling agent and blended into general-purpose resins such as polyolefin resins, polyamide resins, and polyester resins. A method of imparting conductivity to a compound is disclosed.

However, molded products obtained by injection molding a composite material made by kneading metal flakes surface-treated with the above-mentioned silane-based or titanium-based coupling agent and an organic resin still have the following problems.
Mechanical properties such as tensile strength, bending strength, and rigidity are insufficient, and there are problems in practical use.

<Objective of the Invention> The object of the present invention is to solve the above-mentioned conventional problems, to treat the surface of small flaky metal with a reaction product of an epoxy group-containing compound and silyl isocyanate, and to improve the bonding strength with various organic resins. The object of the present invention is to provide a flaky metal-resin composition that is a composite material that is reinforced and has improved mechanical properties such as tensile strength, bending strength, stiffness, street resistance, and abrasion resistance.

<Structure of the Invention> The present invention is characterized in that a small flaky metal having a maximum diameter of 1 to 40 and an aspect ratio of 20 to 100, whose surface has been previously treated with a reaction product of an epoxy group-containing compound and silyl isocyanate, is applied to an organic resin. The object of the present invention is to provide a small flake-like metal-resin composition, characterized in that the composite contains 1 to 90 wtt.

The present invention will be explained in detail below.

The present invention is a composite material from which a molded article with excellent dimensional accuracy and mechanical properties can be obtained, and has the following characteristics.

■Since the small flaky metal has an appropriate size and thickness, it is well dispersed and properly oriented in the organic resin during injection molding.

(2) The surface of the small flaky metal is treated with a reaction product of an epoxy group-containing compound and silyl isocyanate prior to kneading with the organic resin, so it has high adhesion with the organic resin.

That is, the present inventors used surface-treated small flaky metal as a metal filler to be mixed into a composite material with an organic resin. It was discovered that a molded product with excellent mechanical properties could be obtained due to the high adhesion with the resin, and the present invention was completed.

The metal material of the small flake metal used in the present invention is Cu,
Any metal having corrosion resistance such as Ni, Zn, All, stainless steel, brass, bronze, or alloys thereof can be used.

The shape of the small flaky metal used in the present invention has a maximum particle size of 1
-40-1 It is preferable that the aspect ratio defined by the ratio of maximum grain size to thickness is 20 to 100. The reason for this is that if the maximum particle size is less than 1 or the aspect ratio is less than 20, the composite material cannot have sufficient mechanical strength even if it is composited with an appropriate surface treatment as described below.

In addition, if the maximum particle size exceeds 40 or the aspect ratio exceeds 100, the small flaky metal of this shape will be too oriented in the molded product, resulting in dimensional accuracy, especially in the gate direction (P51 fat flow direction) and the direction perpendicular to the gate (flow right angle direction). This is because problems such as anisotropy occurs and the roundness deteriorates.

Next, the small flaky metal used in the present invention is added to the organic resin.
It is preferable to combine at a ratio of 90 wtJ. The reason for this is that sufficient strength cannot be obtained with a composite of less than 1wt%, and 90w
This is because the dimensional accuracy decreases with a combination of more than t't;

The organic resin used in the present invention may be any thermoplastic resin, whether crystalline or amorphous, such as low density polyethylene, high density polyethylene, polypropylene, polyolefin, polystyrene,
ABS, polyamide, polyamideimide, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polycarbonate, polyphenylene oxide, polysulfone, bophenylene sulfone, polyarylate, polyether sulfone, polyether ether ketone, polyether imide and polyoxybenzoyl, etc. Resins are preferred.

The small flaky metal used in the present invention is surface-treated with a reaction product of an epoxy group-containing compound and silyl isocyanate prior to compounding by kneading with an organic resin. The reason for this is that silyl isocyanate has an extremely strong affinity or reactivity with the flaky metal surface. This is because, by bonding an epoxy group-containing compound having a group that reacts with the NGO group of the silyl isocyanate, the flaky metal surface can be made highly hydrophobic. That is,
This is because, as a surface treatment agent, this reactant has a high affinity with the flaky metal surface and has an organic group for sufficient integration with the organic resin to be composited.

Silyl isocyanate, which is the first component of the reactant as a surface treatment agent that binds to the flaky metal, is Rn Si
(NGO) 4- Represented by n, where n is 0, 1.2
and 3, R is an alkyl group, an allyl group, or an alkoxyl group having 1 or more carbon atoms.

Any second component of the above-mentioned reactant as a surface treatment agent may be used as long as it contains ashes, reacts with silyl isocyanate, and has a strong bonding force with the organic resin, but in particular, those having unsaturated bonds are suitable. preferable. Typical examples thereof include glycidyl acrylate, glycidyl methacrylate, and epoxy resin.

Further, the reaction between the epoxy group-containing compound and the silyl isocyanate is preferably such that 1 mole or more of the silyl isocyanate is reacted per equivalent of the epoxy group-containing compound. The reason for this is that an effective substance cannot be obtained with less than 1 mol. Furthermore, the surface treatment of small flaky metals using the reactant obtained as a surface treatment agent is performed by adding the reactant in an amount of 0.5 to 30% in terms of solid content based on the weight of the metal, and performing the treatment at a temperature higher than room temperature. Or preferable. The reason for this is that if it is less than 0.5%, it is difficult to obtain the effect, and if it is added in excess of 30%, the effect is saturated and is useless.

<Examples> Next, the present invention will be specifically described with reference to Examples and Comparative Examples.

(Example 1) Shrimp chlorbidrin-bisphenol type epoxy resin (
186 g of epoxy 186) and 169 g of methylsilyl triisocyanate were reacted with 645 g of toluene at 120° C. for 1 hour to obtain a reaction product (D).

Using this reaction product (D), stainless steel flakes were treated at a concentration of 2% in terms of solid matter to obtain a surface-treated product (A).

This surface treated product (A) 30wt%; and polyacetal 7
0wt! A test piece and a reduction gear with a wall thickness of 1.5 mm and a maximum diameter of 26 mm were made by injection molding using a compound made by kneading garlic.

(Example 2) 479 g of a copolymer of glycidyl methacrylate and acrylic acid (epoxy fi529), 153 g of methyl isocyanate, and 900 g of toluene were reacted at 120° C. for 1 hour to obtain a reaction product (E). Stainless steel flakes were treated with this reaction product (E) at a concentration of 2 wt (calculated as solid matter) to obtain a surface-treated product (B). This surface treated product (B)
A compound was prepared by kneading 30 wt%; and 70 wt% of polyacetal, and the compound was injection molded to obtain a test piece and a reduction gear with a wall thickness of 1.5 mm and a maximum diameter of 26 tntn.

(Example 3) 30 wt% of the surface treated product (A) and 70 wtJ of ABS resin were kneaded, and the same procedure as in Example 1 was carried out to obtain a test piece and a reduction gear.

(Example 4) 30 wt% of the surface treated product (B) and 70 wt% of ABS resin were kneaded to obtain the same test piece and reduction gear as in Example 2.

(Example 5) Aluminum flakes were treated with the reaction product (D) at a concentration of 1% in terms of solids to obtain a surface-treated product (C). This surface treated product (C) is 30wL! Nito polycarbonate 70w
t%; was kneaded, and the same procedure as in Example 1 was carried out to obtain a test piece and a reduction gear.

(Comparative Example 1) A test piece and a reduction gear having a wall thickness of 1.5 mm and a maximum diameter of 26 mm were made by injection molding using a polyacetal pellet.

(Comparative Example 2) A test piece and a reduction gear with a wall thickness of 1.5 mm and a maximum diameter of 26 m+n were made by injection molding using an ABS resin pellet.

(Comparative Example 3) A test piece and a reduction gear having a wall thickness of 1.5 mm and a maximum diameter of 26 mm were made by injection molding using a polycarbonate pellet.

The following material tests were carried out using the test pieces obtained in Examples 1 to 5 and Comparative Examples 1 to 3, and dimensional accuracy inspection was carried out using the obtained reduction gears, and the test results are shown in Table 1. show.

(a) Material test (1) The tensile strength and tensile elongation (elongation at break) of each test piece were determined by a tensile test (ASTM D638
by).

(2) The bending strength and bending elastic modulus of each test piece were determined by a bending test (according to ASTM D790).

(3) The impact value of each test piece was determined by an Izot impact test (according to ASTM D256).

(Inspection of dimensional deviation (4) Shrinkage rate It was determined from the ratio of the molded product size and mold size of each transmission gear.

(5) Roundness The difference between the diameters of each transmission gear in the gate direction and in the direction perpendicular to the gate was determined.

As is clear from Table 1, when polyacetal is used as the organic resin, Examples 1 and 2, which are the small flaky metal-resin compositions of the present invention, are more effective in tensile tests than Comparative Example 1, which is made only of polyacetal. It has shown excellent results in material tests consisting of bending tests and impact tests, and has also shown excellent results in dimensional accuracy tests consisting of shrinkage rate and roundness.

In addition, Examples 3 and 4 using ABS resin as the organic resin show excellent results in both the material test and the dimensional accuracy test, even when compared with Comparative Example 2.

In addition, Example 5, which used polycarbonate as the organic resin, showed excellent results in both the material test and the dimensional accuracy test, even when compared with Comparative Example 3.

As described above, all of the examples of the present invention show good test results, and it can be seen that they are composite materials with high dimensional bulk and excellent mechanical properties.

<Effects of the Invention> According to the present invention, a small flaky metal-resin composition having excellent dimensional accuracy and mechanical properties can be obtained.

The flaky metal-resin composition of the present invention is a mixture of a silyl isocyanate that has an extremely strong affinity with the surface of the flaky metal and an epoxy-containing compound that reacts well with the silyl isocyanate and has a strong bonding force with an organic resin. Because it is a composite material of the above-mentioned flaky metal and organic resin that has been surface-treated by Moreover, it is a composite material with greatly improved dimensional accuracy and dimensional stability. Therefore, the flaky metal-resin composition of the present invention is most suitable as a material for mechanical parts such as gears and cams that require mechanical strength and dimensional stability.

Claims (1)

[Claims] The maximum diameter is 1 to 40, which has been surface-treated in advance with a reaction product of an epoxy group-containing compound and silyl isocyanate.
1. A small flaky metal-resin composition comprising a composite of small flaky metal having an aspect ratio of 20 to 100 and containing 1 to 90 wt% based on an organic resin.