JPS5853663B2 - Resin composition for mica filling molding - Google Patents

Description

Detailed Description of the Invention The present invention provides (a) poly(1,4-butylene terephthalate) resin (hereinafter abbreviated as PBT resin), (b) poly(1,4-butylene terephthalate) as a hard segment; The present invention relates to a molding resin composition containing as essential components a block copolymer comprising polytetramethylene glycol as a soft segment and (c) mica powder having a diameter of 50 μm or less.

Mixing various reinforcing materials and reinforcing fillers with PBT resin is known, for example, from Japanese Patent Publication No. 4812412.48-12413.

On the other hand, it was reported in Japanese Patent Publication No. 49-18615 that by blending mica powder with various resins, compositions with extremely excellent elastic modulus, dimensional and form stability, heat resistance, and strength can be obtained.
Publication No. 33rd, which has already been published on PBT resin mixed with mica powder, for example, 33rd
SPI Annual Technical Conf
erence 5ection 2-D (1978)
etc., by mixing mica powder, PBT
It has been found that the elastic modulus, heat resistance, strength, dielectric breakdown voltage, etc. of the resin are significantly improved, and it is known that it is a useful material for electrical parts and mechanical parts.

However, PBT resin mixed with mica powder is inferior to PBT resin filled with various fillers such as talc.
Although the effect of improving the elastic modulus, heat resistance, and strength is good, and there are no problems such as anisotropy of physical properties of molded products and appearance of warpage, which are seen with glass fiber mixed PBT, on the other hand, impact strength is It has the disadvantage of being low.

Furthermore, the impact strength of PBT mixed with mica powder can be improved by using a reinforcing material having a fibrous form, such as glass fiber, but PBT resin mixed with mica powder and glass fiber can be improved in the region where the mixing ratio of glass fiber is relatively low. However, the disadvantage is that warping and twisting occur in the molded product, making it difficult to achieve the dimensional stability of the molded product, which is the most important feature of mica powder-containing PBT resin.

However, the inventors of the present invention have conducted intensive research into methods for improving the impact strength of PBT resins containing mica powder without impairing the characteristics such as non-solidity, high elastic modulus, and high heat distortion temperature. A part of the PBT resin component of the composition consisting of PBT resin is replaced with a block copolymer in which poly(1,4-butylene terephthalate) is used as a hard segment and polytetramethylene glycol is used as a soft segment. It was discovered that the desired goal could be achieved by using a powder of 50 μm or less, and the present invention was completed.

The PBT resin used in the present invention is mainly a polyester containing butylene glycol as a glycol component and terephthalic acid as a dicarboxylic acid component, but a small amount of this component is used as a glycol component such as ethylene glycol, propylene, etc. Glycol, decamethylene glycol, etc. may be used, and the dicarboxylic acid component may be replaced with, for example, phthalic acid, isophthalic acid, hexahydroterephthalic acid, naphthalenedicarboxylic acid, adipic acid, sebacic acid, azelaic acid, etc.

There is no particular restriction on the intrinsic viscosity (phenol/tetrachloroethane=1/1,30'C) of the PBT resin, but it is preferably 0.6 or more, more preferably 0.8 or more.

The block copolymer used in the present invention is a copolymer with crystalline poly(1,4-butylene terephthalate) as a hard segment and non-grade polytetramethylene glycol as a soft segment. 4
-butylene terephthalate) component and polytetramethylene glycol component. When the weight of the poly(1,4-butylene terephthalate) component is 1, the weight of the polytetramethylene glycol is 0.2 to 2.5. Must be within the range.

When using a block copolymer in which the weight of polytetramethylene glycol is 0.2 or less, the effect of improving the impact strength of the molded article is small, and when using a block copolymer in which the weight of polytetramethylene glycol is 2, 5 or more, the molded article Although the impact strength is improved, the reduction in heat distortion temperature is significantly undesirable.

Incidentally, the block copolymer may contain a small amount of other components within a range that does not significantly change the performance of the copolymer, particularly the melting point, rubber elasticity behavior, etc.

On the other hand, the mica powder used in the present invention can be widely selected from muscovite (muscovite), phlogopite (phlogovite), synthetic phlogovite, etc., but PBT
Kneading with resin and injection molding temperature, i.e. 230-2
It is desirable that water of crystallization does not separate in a temperature range up to 80°C.

It is necessary that the diameter of the mica powder used in the present invention is 50 μm or less.

If the diameter of the mica powder exceeds 50 μm, even if the specific block copolymer described above is used, it will be difficult to obtain a satisfactory value for impact strength, especially falling ball impact strength. This is not desirable because flaking of the mica powder from the surface of the molded product may occur in this region.

There are no particular restrictions on the ratio of the diameter and thickness of the mica powder, that is, the aspect ratio, but if a significant improvement in the elastic modulus, strength, or thermal properties of the molded product, such as heat distortion temperature, is expected, the aspect ratio should be 10 or more. It is desirable that there be.

The composition of the present invention has a PBT resin component weight of A1 poly(1
, 4-butylene terephthalate)/polytetramethylene glycol block copolymer and the weight of the mica powder is C, the composition ratio thereof needs to be within the following range.

As shown in the first formula, the blending ratio of mica powder in the composition of the present invention needs to be 10 to 60% by weight.

When the mixing ratio of mica powder is 10% by weight or less, the effect of improving the mechanical properties and thermal properties of the molded article based on the composition is insufficient.

On the other hand, if the mixing ratio of mica powder exceeds 60% by weight, the fluidity of the composition will be extremely reduced, making it difficult to mold, and even if the block copolymer described above is used, good impact strength will not be obtained. I can't.

As shown in the second formula, the mixing ratio of the block copolymer needs to be 5 to 30% by weight of the resin component in the composition.

When the mixing ratio of the block copolymer is 5% by weight or less, the effect of improving impact strength is insufficient. On the other hand, when the mixing ratio of the block copolymer is 30% by weight or more, the impact strength is Although good, heat distortion temperature, elastic modulus, strength, etc. are significantly reduced.

Various additives can be added to the composition of the present invention as required.

In particular, the addition of additives to improve the interfacial adhesive strength between the mica powder and the resin, such as a silane coupling agent, is extremely effective in improving the physical properties of the molded product in both the dry and wet states.

In addition, blending a small amount of glass fiber is extremely effective in improving various mechanical properties such as impact strength, and thermal properties, and blending glass with a flake-like form suppresses warping of molded products and improves elasticity. It is effective in improving the heat deformation temperature and heat distortion temperature.

Antioxidants, especially amine-based antioxidants, are effective in preventing deterioration of mechanical properties when molded articles based on the composition of the present invention are used at high temperatures for long periods of time.

In addition, various known additives such as antistatic agents, lubricants, and colorants can be used as necessary.

The composition of the present invention can be applied to molded products that require dimensional stability, rigidity, heat resistance, electrical insulation, etc., such as electrical parts, mechanical parts, and structural parts, by methods such as injection molding, extrusion molding, and compressing. is formed into.

Hereinafter, the method of the present invention will be explained in more detail with reference to Examples and Comparative Examples, but these Examples are not intended to limit the scope of the present invention.

Example 1 54 parts of PBT resin with an intrinsic viscosity of 1.1, 6 parts of a block copolymer with a weight ratio of poly(1°4-butylene terephthalate) and polytetramethylene glycol of 1:2.2, and gold with an average diameter of 40μ After thoroughly mixing 40 parts of mica powder and 0.2 parts of γ-aminopropyltrimethoxysilane in a Henschel mixer, the mixture was fed to an extruder and melt-kneaded and extruded at 250°C to obtain pellets.

The pellets were fed to an injection molding machine and the cylinder temperature was 250.
Injection molding was performed under conditions of ℃ and mold temperature of 60℃.
A molded article with a diameter of 15% and a thickness of 0.2 CrrL was obtained.

The warpage of the molded product was measured using the method shown in FIG. 1, and the falling ball impact strength was also measured using a steel ball with a diameter of 5% and a weight of 500 g.

On the other hand, under the same injection molding conditions, the width was 1.3% and the thickness was 0.
A test piece of 3 crn was prepared, and the heat distortion temperature was measured under a load of 18.6 kg/-.

As shown in Table 1, the measurement results showed that satisfactory values were obtained for all of the falling ball impact strength, thermal deformation temperature, and molded product warpage.

Example 2 48 parts of PBT resin with an intrinsic viscosity of 1.1, 12 parts of a block copolymer with a weight ratio of poly(1°4-butylene terephthalate) and polytetramethylene glycol of 1:0.7, and gold with an average diameter of 40μ 40 parts of mica powder and 0.2 parts of γ-aminopropyltrimethoxysilane were pelletized and injection molded under exactly the same conditions as in Example 1 to obtain a molded product.

As shown in Table 1, the performance of the obtained molded product was satisfactory.

Example 3 48 parts of PBT resin with an intrinsic viscosity of 1.1, 12 parts of a block copolymer with a weight ratio of poly(1°4-butylene terephthalate) and polytetramethylene glycol of 1:0.3, and gold with an average diameter of 40μ Mica Powder 40 The γ-aminopropyltrimethoxysilane portion was pelletized and injection molded under exactly the same conditions as in Example 1 to obtain a molded product.

As shown in Table 1, the performance of the resulting molded product was somewhat insufficient, but it was observed that the ball impact strength was improved.

Comparative Example 1 60 parts of PBT resin with an intrinsic viscosity of 1.1, 40 parts of phlogopite powder with an average diameter of 40 μm, and 0.0 parts of γ-aminotrimethoxysilane.
Two parts were pelletized and injection molded under exactly the same conditions as in Example 1 to obtain a molded product.

As shown in Table 1, the falling ball impact strength was extremely low.

Comparative Example 2 A molded article was obtained by injection molding pellets prepared using the same recipe and method as in Example 1, except for using phlogopite powder with an average diameter of 120 μm, under the same conditions as in Example 1.

As shown in Table 1, the falling ball impact strength was inferior to that of the composition of Example 1.

Comparative Example 3 Pellets were prepared and injection molded using the same composition and method as in Example 1, except that phlogopite powder with an average diameter of 250 μm was used.

As shown in Table 1, when compared with the composition of Comparative Example 1,
No improvement in falling ball impact strength was observed.

Comparative Example 4 Pelletization was performed using exactly the same composition and method as in Example 2, except that a block copolymer with a weight ratio of poly(1,4-butylene terephthalate) and polytetramethylene glycol of 1:0.15 was used. A molded product was obtained by injection molding, but no significant improvement in falling ball impact strength was observed.

Comparative Example 5 Pelletization and injection molding were carried out using the same composition and method as in Example 2, except that a block copolymer with a weight ratio of poly(1,4-butylene terephthalate) and polytetramethylene glycol of 1:3 was used. was carried out.

As shown in Table 1, the molded product has excellent falling ball impact strength, but the heat distortion temperature is significantly lowered.

Comparative Example 6 Exactly the same composition as Example 1, except that the mixing ratio of PBT resin was changed to 58 parts and the mixing ratio of poly(1,4-butylene terephthalate)/polytetramethylene glycol block copolymer was changed to 2 parts. A molded product was obtained by pelletizing and injection molding using the following method.

As shown in Table 1, the impact strength improvement effect was small.

Comparative Example 7 Exactly the same composition and method as in Example 3, except that the blending ratio of PBT resin was changed to 36 parts and the blending ratio of poly(1,4-butylene terephthalate)/polytetramethylene glycol block copolymer was changed to 24 parts. A molded product was obtained by pelletizing and injection molding.

As shown in Table 1, the falling ball impact strength was good, but the heat distortion temperature was significantly lowered.

Comparative Example 8 70 parts of PBT resin with an intrinsic viscosity of 1.1, 30 parts of glass fiber surface-treated with γ-aminopropyltrimethoxysilane
A part was pelletized and injection molded using the same method and conditions as in Example 1 to obtain a molded product.

The molded product has good falling ball impact strength and heat distortion temperature, but warpage is noticeable.

Example 4 54 parts of PBT resin with an intrinsic viscosity of 1.1, 6 parts of a block copolymer with a weight ratio of poly(1°4-butylene lentilphrate) and polytetramethylene glycol of 1:2.2, average diameter 40μ 20 parts of mica powder, 5 parts of glass fiber, 15 parts of glass flakes with an average diameter of 400μ, and 0.2 parts of γ-aminopropyltrimethoxysilane were pelletized and injection molded using the same method and conditions as in Example 1. A molded product was obtained.

As shown in Table 1, the molded product had extremely excellent falling ball impact strength and heat distortion temperature.

Comparative Example 9 Completely the same composition and method as Example 4, except that the poly(1,4-butylene terephthalate)/polytetramethylene glycol block copolymer was not used and the blending ratio of PBT resin was 60 parts. Pelletization and injection molding were performed under the following conditions to obtain a molded product.

As shown in Table 1, the falling ball impact strength of the molded product was poor.

Claims (1)

[Claims] 1 (a) poly(1,4-butylene terephthalate) resin; (b) a block copolymer in which poly(1,4-butylene terephthalate) is used as a hard segment and polytetramethylene glycol is used as a soft segment. And PoI
If the weight of J (1,4-butylene terephthalate) is 1, the weight of polytetramethylene glycol is 0.2
(c) a molding resin composition containing as an essential component a mica powder having a diameter of 50μ or less, wherein the weight of the poly(1° 4-butylene terephthalate) resin is A1 A molding resin composition in which the weight ratio of each component is within the range of the following formula, where the weight of the block copolymer is B1 and the weight of mica powder is C.