JPH0739542B2 - Thermoplastic reinforced resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is excellent in mechanical strength, rigidity, road deicing resistance, dimensional stability when absorbing moisture, warp denaturation prevention, and heat deformation resistance. The present invention relates to a resin composition capable of obtaining an excellent molded article, and more specifically, a resin component composed of a polyamide resin and an unsaturated acid-modified polyolefin, a reinforced resin composition obtained by mixing glass fiber and a plate-like inorganic filler. It is about things.

[Conventional technology]

2. Description of the Related Art In recent years, there has been a noticeable tendency in the fields of automobile parts, electric parts, general machine parts, etc. to use metal as a resin for the purpose of forming workability, weight reduction, and cost reduction. Among them, polyamide resin glass fiber reinforced products are often used because of their excellent properties such as mechanical strength and heat distortion resistance.

However, polyamide resins have the drawback of being inferior in water resistance and road antifreeze resistance. In order to improve these drawbacks, for example, JP-A-1-240560 and JP-A-1-240560
No. 240561 and Japanese Patent Publication No. 63-53127 are proposed.

However, in these known methods, although the drawback of the polyamide resin inferior in water resistance and road antifreeze resistance is improved, the drawback that the warp deformation of the molded article becomes large on the contrary (especially when used at high temperature) appears. However, its use in applications requiring dimensional accuracy was severely limited. This important study on dimensional stability has never been conducted in the above-mentioned prior documents.

[Problems to be Solved by the Invention]

An object of the present invention is to provide a resin composition having excellent mechanical stability, water resistance, road antifreeze resistance and heat distortion resistance, and less dimensional change due to warp deformation and moisture absorption and excellent dimensional stability of molded products. Is to provide.

[Means for Solving the Problems]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a polyamide resin and a polyolefin are contained in a resin composition using a specific composition ratio and a specific melt flow rate ratio, a glass fiber and a plate. It has been found that the above-mentioned problems can be solved all at once by filling a particulate inorganic filler at a specific composition ratio, and the present invention has been reached.

That is, the thermoplastic reinforced resin composition of the present invention is (a) a polyamide for a melt flow rate of a modified polyolefin composed of a mixture of a polyolefin modified with an unsaturated acid and an unmodified polyolefin or a polyolefin modified with an unsaturated acid. The ratio of the melt flow rate of the resin is 0.5 or more, the total consisting of 80 to 50% by weight of the polyamide resin and 20 to 50% by weight of the modified polyolefin.
100% by weight of resin component 75 to 50% by weight (b) Glass fiber 10 to 40% by weight and (c) Plate-like inorganic filler with aspect ratio of 25 or more 15 to
40% by weight (wherein (a) + (b) + (c) is 100% by weight).

As the polyolefin modified with an unsaturated acid, a modified polypropylene grafted with an unsaturated acid or a derivative thereof is preferable. Graft ratio of unsaturated acid or its derivative in modified polypropylene is 0.2% by weight
The above is preferable.

Further, mica is preferable as the plate-like inorganic filler having an aspect ratio of 25 or more.

Flow properties of polyamide resin, ie 230 ℃ or 290
Melt flow rate (hereinafter abbreviated as MFR) measured by the amount of molten resin released for 10 minutes when a load of 2.16 is applied at ℃ can be any value. The MFR is compared with the MFR at the same temperature as the polyamide resin, and is characterized by specifying the MFR of the polyamide resin used. That is, M of polyamide resin to MFR of modified polyolefin
M of modified polyolefin so that the ratio of FR is 0.5 or more
Determine FR.

The polyamide resin used in the present invention means nylon 4 produced by polycondensation of diaminobutane and adipic acid.
6, MXD-6 produced by polycondensation of metaxylenediamine and adipic acid, nylon 6 of aliphatic polyamide, nylon 66 and the like, and a mixture thereof may be used.

The MFR as a fluidity characteristic of these polyamide resins does not need to be limited and can be selected from any commercially available products.

The modified polyolefin used in the present invention may be a modified polyolefin grafted with an unsaturated acid or a derivative thereof, or may be a mixture of this grafted modified polyolefin and an unmodified polyolefin.
In this case, the ratio of the MFR of the polyamide resin to the modified polyolefin shall be the MFR of the mixture. The graft-modified polyolefin is a polyolefin grafted with an unsaturated acid or a derivative thereof obtained by reacting a polyolefin unsaturated acid with a radical generator in the presence of a radical generator. .

The unsaturated acid graft ratio of the modified polyolefin is
In the -53217 publication, the heat distortion resistance is realized by sacrificing the compatibility by setting the upper limit of the graft ratio, but in the composition of the present invention, it is not particularly limited, and is 0.2% by weight or more. Even if there is, a composition having sufficiently excellent heat distortion resistance can be obtained.

Therefore, the molded article comprising the composition of the present application is remarkably excellent in compatibility with the polyamide and the modified polyolefin,
The dimensional stability is extremely good not only at room temperature but also under the condition of heat treatment at high temperature.

On the other hand, the composition of the prior art has a problem that the amount of warp deformation itself at room temperature is considerably large, and the amount of warp deformation becomes larger under heat treatment conditions, which is a significant limitation in application. was there. (The difference between the warp deformation amount at room temperature and the warp deformation amount at the time of heat treatment is influenced by the graft ratio in the modified polyolefin, and becomes remarkable when the graft ratio is low.) It is also excellent in that a molded product having a good appearance can be obtained.

The polyamide resin that can be used in the present invention has a specific
There is no need to limit to those having MFR, and any commercially available one can be arbitrarily selected. However, the modified polyolefin that can be used in the present invention needs to be selected in conjunction with the polyamide resin MFR used, and the MFR of the polyamide resin MFR of the modified polyolefin
Must be greater than 0.5. This MFR ratio is 0.
When it is less than 5, the heat distortion temperature of the composition is surprisingly lowered. On the contrary, as long as the condition that the MFR ratio is 0.5 or more can be maintained, the MFR of the modified polyolefin that can be used in the composition of the present invention is not particularly limited and has a feature that it can be widely selected.

As the unsaturated acid, an unsaturated carboxylic acid or an anhydride thereof,
Examples thereof include acrylic acid, methacrylic acid, maleic acid, phthalic acid, citraconic acid, maleic anhydride, and itaconic anhydride. Of these, maleic anhydride is preferred.

Examples of the polyolefin used for the modified polyolefin include polyethylene, polypropylene, poly α-butylene, α-olefins such as poly α-isobutylene,
Examples thereof include copolymers or mixtures of the α-olefin with other α-olefins and / or other vinyl monomers, with polypropylene being particularly preferred. As the content ratio of the polyamide resin and the modified polyolefin in the resin component used in the present invention, the polyamide resin component is 80% by weight to
It is 50% by weight, preferably 70% to 55% by weight.

If it exceeds 80% by weight, the effect of improving road anti-icing resistance and dimensional stability during water absorption is small.

If it is less than 50% by weight, the heat distortion temperature as the heat distortion resistance is remarkably lowered.

Modified polyolefin is 20% to 50% by weight, preferably
30% to 45% by weight.

If it exceeds 50% by weight, the heat distortion temperature is remarkably lowered, and if it is less than 20% by weight, the effects of improving road anti-icing resistance and dimensional stability when absorbing water are lowered.

The resin component as the total of the polyamide resin and the modified polyolefin needs to be 75 to 50% by weight. 75% by weight
When it exceeds the above range, either or both of the glass fiber and the inorganic filler become insufficient, and sufficient mechanical strength and heat distortion temperature cannot be obtained. If it is less than 50% by weight, the moldability will be deteriorated.

The glass fiber used in the present invention is a glass chopped strand that is usually produced for resin reinforcement, and has an average fiber diameter of 5 to 20 μm and an average fiber length of 0.5 mm or more.
It is preferably 0 mm or less.

The content of glass fibers is 10-40% by weight in the total composition. If it is less than 10% by weight, the mechanical strength and heat distortion temperature are insufficient, and if it exceeds 40% by weight, the moldability of the molded product is deteriorated and the commercial value is impaired.

Examples of the plate-like inorganic filler used in the present invention include talc and mica, but mica is particularly preferable. These inorganic fillers preferably have an average diameter to average thickness ratio, that is, an average aspect ratio of 25 or more.

The content of inorganic filler is 15-40% by weight in the total composition. If it is less than 15% by weight, the effect of preventing warpage and deformation of the molded product is insufficient, and the unsaturated acid graft ratio in the modified polyolefin is limited to a specific range or less, and the compatibility between the polyamide resin and the modified polyolefin is significantly sacrificed. Otherwise, a sufficiently high heat distortion temperature cannot be obtained. Again 40
When the content exceeds the weight%, the appearance of the molded product is deteriorated and the commercial value is impaired.

If the total content of glass fiber and mica exceeds 80% by weight, not only will industrial production be difficult, but the moldability will be extremely deteriorated and the commercial value will be impaired. Is preferably 80% by weight or less.

The composition of the present invention can be produced by the following method. That is, for example, 1) polyamide resin, modified polyolefin, glass fiber and mica are put in a predetermined amount in a high-speed stirrer, and after stirring and mixing, a resin temperature of 230 to 300 ° C. using a uniaxial or biaxial extruder, Preferably 230-280 ℃
Method of melt kneading and extruding. 2) A material obtained by stirring and mixing a predetermined amount of each of polyamide resin, modified polyolefin and mica is supplied from an ordinary material supply port, and after the mixture is sufficiently melt-kneaded, another material can be supplied on the way. In an extruder having an addition port, a predetermined amount of glass fiber is supplied from an addition port on the way, and melt-kneaded at the above resin temperature,
It is a method of pushing out. In addition, various additives such as an antioxidant, a copper damage inhibitor, a crystal nucleating agent, a release agent, and a pigment can be used in combination in the composition of the present invention.

〔Example〕

The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The measurement of the effect of the present invention is as follows: 1) Heat distortion temperature (load: 18.6 kg / c)
The m ²⁾ Measurement of (JIS7207), 2) a tensile strength measurement of the (J
IS K6728) 3) Measurement of flexural modulus (JIS K720
According to 7), 4) Measurement of dimensional stability when absorbing water is based on the rate of change from the thickness before water absorption treatment after leaving JIS No. 1 tensile test piece for 1000 hours at 50 ° C and 95% RH in a constant temperature and humidity chamber. 5) Anti-freeze resistance against road anti-freezing property is obtained by fully absorbing a saturated aqueous solution of calcium chloride in absorbent cotton set on a tensile test piece and leaving it for 1 hour in a hot air dryer at 100 ° C with a 1 kg weight applied horizontally. Then, after taking out and leaving it at room temperature for 0.5 hours, the absorbent cotton on the tensile test piece is fully absorbed with calcium chloride saturated aqueous solution again, and it is left in the hot air dryer for 1 hour and at room temperature for 0.5 hour. The presence or absence of the occurrence of surface cracks was evaluated, and the symbol "O" indicates that the surface cracks did not occur, and the symbol "X" indicates the occurrence. 6) The warp deformability was measured by measuring the maximum warp deformation amount shown below.

Maximum amount of warp deformation: A flat plate with a thickness of 2 mm and a length and width of 150 mm was created as a film gate on one side.
The obtained flat plate as a test piece, the test piece at a temperature of 23 ℃,
Conditioning was performed for 48 hours under the condition of RH 50%. After that, the test piece was fixed on a horizontal table at both ends of one side, and the distance (warp) away from the horizontal plane at the other end was measured and defined as the warp deformation amount. However, since the amount of warpage deformation varies depending on the position of one side of the test piece that is fixed, the position of one side that is fixed is variously changed to measure the amount of warpage deformation at the other end. The amount is expressed in mm. 7) The warp deformability during heating is 2) after the same test piece as in 6) was treated with a hot air circulation dryer at 120 ° C for 3 hours.
Conditioning was carried out for 48 hours under the condition of 3 ° C and RH50%, and the warp deformation amount was measured by the same method as 6).

(Example 1) Graft ratio of maleic anhydride is 3.2% by weight, MFR (temperature 230
Modified polypropylene (hereinafter referred to as PP-G) with a molten resin discharge rate of 10 minutes when a load of 2.16 kg at ℃ is added is 36.
3.125 wt% and MFR 9.8 unmodified polypropylene homopolymer (hereinafter referred to as PP-1) 21.875 wt% and MF
37.5 wt% of R58 nylon 6 (hereinafter referred to as PA-1) and 37.5 wt% of mica having an aspect ratio of 30 were placed in a high-speed stirrer and mixed by stirring for 1 minute.

The graft ratio of the modified polyolefin composed of PP-G and PP-1 in the mixture was 0.4% by weight and the MFR was 11.6, and the MFR ratio of PA-1 to the modified polyolefin was 5.0.

Using a twin-screw extruder having a raw material supply port with a diameter of 45 mm and L / D30, the mixture was supplied in a fixed amount from a normal raw material supply port, and another part provided in a part of a cylinder was used. 20% by weight of glass fiber (chopped strand, hereinafter referred to as GF) having a strand diameter of 13 μm and a length of 3 mm is supplied from a supply port, a melt-kneading temperature of 250 ° C., and a screw rotation speed of 2
Extrusion pelletization was performed under the conditions of 00 rpm.

The pellets obtained here are dried in a hot air dryer at 100 ° C for 2 hours, and then the temperature of the cylinder is 280 ° C by an injection molding machine.
A predetermined test piece was molded at a mold temperature of 50 ° C. and subjected to various evaluation tests. The results are shown in Table 1.

Examples 2 to 3 The same procedure as in Example 1 was carried out except that the composition ratio of GF and mica was changed as shown in Table 1.

(Example 4) As shown in Table 1, except that nylon 6 having an MFR of 8.0 (hereinafter referred to as PA-2) and MFR of unmodified polypropylene were changed to 4.8 (hereinafter referred to as PP-2), respectively. I went the same way. The modified polyolefin obtained by mixing PP-G and PP-2 had an MFR of 6.1.

(Example 5) The same procedure as in Example 1 was carried out as shown in Table 1 except that the MFR of the unmodified polypropylene was changed to 116 (hereinafter referred to as PP-3). The modified polyolefin obtained by mixing PP-G and PP-3 had an MFR of 100.

(Example 6) PA-1 nylon 6 having a MFR of 120 under a temperature of 290 ° C
The same procedure as in Example 1 was performed as shown in Table 1 except that the number was changed to 6 (hereinafter referred to as PA66). In addition, the MFR of the modified polyolefin obtained by mixing PP-G and PP-1 is 4 at 290 ° C.
It was 6.9.

(Examples 7 to 8) The same procedure as in Example 1 was carried out except that the amounts of the components of PA-1, PP-G and PP-1 were changed as shown in Table 1.

The MFR of the modified polyolefin obtained by mixing PP-G and PP-1 was 11.2 in Example 7 and 13.1.

(Example 9) Example 9 was performed in the same manner as in Example 1 except that the compounding ratios of the resin component, mica and GF were changed as shown in Table 1.

(Comparative Example 1) The same procedure as in Example 1 was carried out as shown in Table 2 except that only PA-1 was used as the resin component and the GF alone was used instead.

(Comparative Example 2) The same procedure as in Example 1 was carried out as shown in Table 2 except that the compounding amount of PP-G in the resin component was changed to GF alone.

The graft ratio in the modified polyolefin obtained by mixing PP-G and PP-1 was 0.01% by weight, and the MFR was 9.8.

(Comparative Examples 3 to 5) The same procedure as in Example 1 was performed as shown in Table 2 except that the filling amounts of GF and mica were changed.

Comparative Example 6 The same procedure as in Example 1 was carried out as shown in Table 2 except that MFR of unmodified polypropylene was changed to 63 (hereinafter referred to as PP-4) and PA-2 was used.

The modified polyolefin obtained by mixing PP-G and PP-4 had an MFR of 59.

(Comparative Example 7) The same procedure as in Example 1 was carried out as shown in Table 2 except that MFR of unmodified polypropylene was changed to 205 (hereinafter referred to as PP-5) and PA-1 was used.

The MFR of the modified polyolefin obtained by mixing PP-G and PP-5 was 169.

(Comparative Examples 8 to 9) The procedure of Example 1 was repeated except that the resin components were changed as shown in Table 2.

The MFR of the modified polyolefin obtained by mixing PP-G and PP-1 is the same as in Example 1.

(Comparative Examples 10 to 11) The same procedure as in Example 1 was carried out except that the compounding ratios of the resin component, mica and GF were changed as shown in Table 2.

As is clear from Table 1 and Table 2, in Example 1 using the composition of the present invention, as compared with Comparative Example 1 in which only PA-1 was used as the resin component and only GF was mixed, the amount of warpage and heating The amount of warpage deformation afterwards was greatly improved, and the dimensional stability during water absorption and road anti-icing agent resistance were also improved.

In Comparative Example 2, the compounding amounts of the resin components PP-G and PP-1 were changed, in Comparative Example 3, the resin component was the same as in Example 1, and only GF was compounded.

Compared with Example 1, in Comparative Example 2, the warp deformation amount was significantly deteriorated even under normal conditions, and was further significantly deteriorated after the heat treatment. In Comparative Example 3, the warp deformation amount was significantly deteriorated and decreased to the heat deformation temperature. Comparative Example 3 is Example 1
It was found that the heat distortion temperature was not improved in the case of GF alone system even though the graft ratio was the same as the above, and that the heat distortion temperature was improved even in the case of the combination of GF and mica even with a high graft ratio. did.

In Examples 2 to 3 and Comparative Examples 4 to 5, the compounding amounts of GF and mica of Example 1 were changed, but only when the amount was within the range of the composition of the present invention, the amount of warp deformation and the warp deformation after heating. The amount is small and the heat distortion temperature is 180 ℃ or higher. If the amount is out of the range of the present invention, the amount of warp deformation is significantly deteriorated or the heat deformation temperature is significantly decreased, so that a composition having both properties is not obtained.

In Examples 4 to 5 and Comparative Examples 6 to 7, the MFR ratio of the PA component to the PP component was changed, and the heat distortion temperature was improved only when the ratio was 0.5 or more, which is within the range of the present invention. It was found that there is no improvement effect when the ratio of MFR, which is outside the scope of the present invention, is less than 0.5.

Example 6 is a product in which PA-1 in Example 1 is changed to PA66, but the warp deformation amount and the warp deformation amount after heating are improved similarly to Example 1, and the heat deformation temperature is further improved by using PA66. Greatly improved.

In Examples 7 to 8 and Comparative Examples 8 to 9, the resin components of Example 1 were changed, but when the content of the polyamide resin was less than 50% by weight or more than 80% by weight, which was outside the range of the present invention. It has been found that the performance which can satisfy the heat distortion temperature, the dimensional stability at the time of absorbing water, and the road anti-icing agent property cannot be obtained at the same time, and the performance is also obtained only within the range of the present invention.

Example 9 and Comparative Examples 10 to 11 are resin components of Example 1,
Although the mixing ratios of mica and GF were changed, the warp deformation amount and the warp deformation amount after heating were small and the heat deformation temperature was 180 ° C. or higher only when the mixing ratio was within the range of the present invention. When the content is out of the range of the present invention, strength and rigidity are decreased, and the amount of deformation after heating is deteriorated, or the heat deformation temperature is significantly decreased, and thus a composition having these properties is obtained. Absent.

[Effects of the Invention] The composition according to the present invention has substantially no warp deformation, less warp deformation during heating, excellent heat deformation temperature, strength and rigidity, less dimensional change due to moisture absorption, and road freezing resistance. It turned out that it has characteristics that combine excellent performance as an inhibitor.
The remarkable effect of the present invention was confirmed.

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Claims (3)

[Claims] 1. The ratio of the melt flow rate of a polyamide resin to the melt flow rate of a modified polyolefin comprising (a) a mixture of a polyolefin modified with an unsaturated acid and an unmodified polyolefin, or a polyolefin modified with an unsaturated acid. 0.5 or more, the polyamide resin 8
A total of 100% by weight of a resin component consisting of 0 to 50% by weight and 20 to 50% by weight of the modified polyolefin, 75 to 50% by weight, (b) 10 to 40% by weight of glass fiber, and (c) a plate having an aspect ratio of 25 or more. Shaped inorganic filler 15 ~
A thermoplastic reinforced resin composition comprising 40% by weight (wherein (a) + (b) + (c) is 100% by weight). 2. A polyolefin modified with an unsaturated acid comprises:
The thermoplastic reinforced resin composition according to claim 1, which is a modified polypropylene grafted with an unsaturated acid or a derivative thereof. 3. The thermoplastic reinforced resin composition according to claim 1, wherein the plate-like inorganic filler having an aspect ratio of 25 or more is mica.