JPS584737B2 - polyamide composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyamide composition, and more particularly to a polyamide composition containing a powdery inorganic substance and having excellent color dispersibility.

Powdered inorganic oxides, carbonates, sulfates, silicates, etc.
It has been widely used as a filler in many plastics.

In the past, it has been used as a filler for thermosetting resins such as phenol resin A epoxy resin, and more recently, it has been used as a filler for polyethylene resins and polypropylene resins for the purpose of resource saving and low calorie combustion.

In contrast, the use of these fillers as reinforcing materials for plastics has been investigated.

The background to this is the development of a technique for bonding the filler and plastic by treating the surface of the filler with an organosilicon compound, a polymerizable organic acid, or the like.

Traditionally, fibrous substances such as glass fiber, carbon resin, and special synthetic fibers have been used as the most effective reinforcing materials for plastics, and glass fiber in particular is used in a wide range of plastics, so much so that it is said to be the representative reinforcing material. It is being said.

However, in a resin containing such a fibrous reinforcing material, the orientation of the reinforcing material is significant, resulting in anisotropy in the reinforcing effect.

Anisotropy in strength and rigidity is also a problem, but a particularly big problem is that molded products tend to warp or deform due to anisotropy in mold shrinkage.

Because of the warpage and deformation of this molded product, its use in various casings is severely limited.

As a result of research to eliminate these drawbacks of fiber-reinforced resins, we have treated the surface of powdered inorganic substances that have conventionally been used simply as fillers, and have developed highly concentrated powdered inorganic substances. A technology for blending it into resins has been developed, and it has been applied to various thermoplastic resins.

As for polyamide resins, the above-mentioned research has been actively conducted, and polyamide compositions having excellent performance have been developed.

This polyamide composition has less warping and deformation, so
The use of it as a material for various casings is being developed, and it is being colored in various colors.

Conventionally, methods for coloring polyamide resins include methods such as a dry blending method of pigments, a kneading method using an extruder, and a masterbatch method using master pellets kneaded with a pigment at a high concentration.

Among these methods, the masterbatch method is preferred in terms of workability and cost.

However, when coloring a polyamide composition containing a powdery inorganic substance at a high concentration, there is a problem in that the pigment is not uniformly dispersed using conventional methods.

A conventional method for improving the dispersibility of pigments has been to apply back pressure to the screw during the molding process to increase the crosstalk effect.

However, in polyamide compositions containing a high concentration of powdered inorganic substances, which are the subject of the present invention, applying back pressure to the screw increases the time required for plasticization, which inevitably lengthens the molding cycle and increases the work required. The disadvantage is that efficiency decreases.

Furthermore, since it contains a high concentration of inorganic substances with relatively high surface hardness, it is possible to tighten the screw by applying back pressure.
Cylinder wear may be accelerated.

From this point of view, in the composition of the present invention, it is not preferable to apply back pressure to the screw.

The present inventors have conducted intensive research to improve the color dispersibility of such polyamide compositions, and as a result, they have discovered a polyamide composition that does not have the above-mentioned drawbacks, and have arrived at the present invention.

That is, the present invention provides 30 to 80% by weight of a powdered inorganic material whose surface has been treated with an organosilicon compound or a polymerizable organic acid.
Glass fiber 1.5 with a fiber length of 50-6,000μ
15% by weight and 0.01 to 5% by weight of a pigment.

By using the composition of the present invention, a molded article with good pigment dispersibility can be obtained without applying any back pressure during molding.

The powdered inorganic substance according to the present invention includes clay, calcined clay,
Calcium carbonate, calcium sulfate, calcium sulfite,
These include calcium silicate, talc, iron, silica, and asbestos.

These powdered inorganic substances preferably have an average particle size of A0.1 to 50μ.

Furthermore, the surface of these powdered inorganic substances has been treated with an organosilicon compound or a polymerizable organic acid, and if a powdered inorganic substance that has not been surface-treated is used, the reinforcing effect is poor.

The blending ratio of the surface-treated powdered inorganic substance is 30 to 80% by weight in the polyamide composition.

Further, it is preferably 35 to 60% by weight.

If the blending ratio is less than 30% by weight, the reinforcing effect will be poor, while if the blending ratio is too high, it will become extremely brittle, and in either case, the effects of the present invention cannot be obtained.

The polyamide according to the present invention is nylon 66, nylon 6, which is obtained by polycondensation of diamine and dicarboxylic acid.
10, nylon 612, nylon 6 obtained by ring-opening polymerization of lactam, nylon 12, nylon 7 obtained by self-polycondensation of ω-aminocarboxylic acid, nylon 11, and copolymers and blends thereof.

The glass fiber according to the present invention may be any fiber that can be used as a reinforcing material for polyamide resin, and its fiber length is 50 to 50.
A material having a thickness of 6,000μ is suitable.

In addition, the blending amount is 15 to 15% for the polyamide composition.
It is 15% by weight.

If the amount of glass fiber blended is less than 1.5% by weight, the effect of dispersing the pigment will be poor, and if it exceeds 15% by weight, the molded product will be noticeably warped, which is not preferable.

The glass fiber may be blended at the same time as the powdered inorganic substance is blended into the polyamide resin, or may be blended either before or after the blending.

The pigment used in the present invention is not particularly limited as long as it can be used for polyamide, and commonly used organic pigments and inorganic pigments can be used, and the amount added is 0. .01 to 5% by weight is suitable.

Specific examples of pigments used in the present invention include various carbon blacks, titanium oxides, cobalt greens, cobalt blues, ultramarine blues, and the like.

Organosilicon compounds used as surface treatment agents for powdered inorganic substances are usually called silane coupling agents, and include γ-aminopropyltrimethoxysilane,
Suitable examples include γ-glycidoxysilane, pyrutrimethoxysilane, and the like.

Further, as the polymerizable organic acid, acrylic acid, methacrylic acid, crotonic acid, etc. are used.

Examples of the present invention will be described below, but the present invention is not limited only to these examples.

Example 1 60 parts by weight of nylon 66 resin, 40 parts by weight of clay surface-treated with γ-aminopyrtrimethoxysilane, and 10 parts by weight of glass fibers having a length of 3 mm were kneaded and pelletized using a 40φ vented extruder.

Separately, master pellets were manufactured by mixing nylon 66 resin with 3% by weight of carbon black.

The weight ratio of the above pellets and color master pellets is 1
Mix at a ratio of 9:1 and process 80% in a 5oz capacity injection molding machine.
A flat sample measuring 50 x 3 mm was molded without applying back pressure.

No color unevenness was observed in this molded article, and it was confirmed that the pigment was uniformly dispersed.

Comparative Example 1 Molding was performed using the same formulation as in Example 1 (except for glass fiber).

When no back pressure was applied, color unevenness of the molded product was significant, and a pattern of light and shade of color was observed parallel to the flow direction.

When a back pressure of about 150 kg/cr1 was applied, color unevenness was hardly observed, but the time required for plasticization tripled, and the molding cycle ended up about twice as long.

Example 2 Master pellets in which 20% by weight of calcium silicate was kneaded in place of the clay of Example 1 and 20% by weight of cobalt blue (+1084 manufactured by Hercules) in place of carbon black were used to mold without applying back pressure.

The appearance of the molded product was good, and no color unevenness was observed.

Example 3 An experiment was conducted using nylon 6 resin instead of nylon 66 resin in Example 1.

The appearance of the molded product was good, and no color unevenness was observed.

Example 4 60 parts by weight of nylon 66 resin, 40 parts by weight of calcium carbonate treated with acrylic acid, 10 parts by weight of glass fiber with a length of 3 mm
Parts by weight were kneaded using a 40φ vented extruder to form pellets.

These pellets and Color Master Peresoto produced in Example 1 were mixed at a weight ratio of 19:1, and a flat sample of 80 x 50 x 3 mm was molded using a 5 oz capacity injection molding machine without applying back pressure.

The appearance of the molded product was good, and no color unevenness was observed.

Comparative Example 2 60 parts by weight of nylon 66 resin, 40 parts by weight of clay treated with γ-aminopyrtrimethoxysilane, length 3 m
1 part by weight of glass fibers of 500 m were kneaded using a 40φ vented extruder and pelletized.

These pellets and the color master pellets produced in Example 1 were mixed at a weight ratio of 19:1 and molded.

The appearance of this molded product is uneven in color, and the back pressure is approximately 100%.
The color unevenness was not resolved unless the amount was reduced to about kg/crt.

Comparative Example 3 Molding was performed in the same manner as in Comparative Example 2, except that 20 parts by weight of glass fibers having a length of 3 mm were used.

Although the appearance of the molded product was good with no color unevenness, anisotropy was observed in the molding shrinkage rate.

Just to be sure, I molded a flat plate of 80 x 50 x 1 mm,
Only molded products with significant warpage and deformation were obtained.

On the other hand, the bereft used in Example 1 is 80X50X
1! When a flat plate of m was molded, a molded product with almost no warping or deformation could be obtained.

As is clear from the above Examples and Comparative Examples, the composition of the present invention has excellent coloring properties, and molded articles with less warpage and deformation can be obtained.

As a result, it is now possible to easily use resin for various types of casings, which were difficult to apply with conventional materials.
It can be said that its industrial value is extremely large.

Claims (1)

[Claims] 1 Powdered inorganic material whose surface has been treated with an organosilicon compound or polymerizable organic acid 30-80% by weight, 50-6,000
A polyamide composition characterized in that it contains 1.5 to 15% by weight of glass fibers having a fiber length of μ and 0.01 to 5% by weight of a pigment.