JPS6198758A - Propylene resin composition - Google Patents

Abstract

PURPOSE:A composition providing a molded article keeping improved strength and heat resistance of FR-PP, having extremely improved rigidity and deformation properties of warping, obtained by blending a modified propylene with glass fibers and specific mica power and kneading them in a molten state. CONSTITUTION:(A) 45-75 wt.% modified polypropylene modified with an unsatu rated acid is blended with (B) 10-35 wt.% glass fibers, and (C) 15-45 wt.% mica powder having >=25, preferably >=45 aspect ratio in such a way that an amount of the components B+C is 25-55 wt.% based on 100 wt.% total amount of the components A+B+C, and a ratio of the component C/the components (B+C) is 0.35-0.82, and kneaded in a molten state. Glass fibers having <=11mu average diameter and >=0.5 mm average length are used as the component B. A modified propylene modified with acrylic acid, metehacrylic acid, maleic acid anhydride fumaric acid, citraconic acid, or itaconic acid is used as the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a propylene resin composition which, when made into a molded article, provides a molded article with excellent mechanical strength, heat-resistant rigidity, and warpage prevention properties.

In order to improve the mechanical strength, rigidity, heat deformation resistance, etc. of polypropylene molded products, various fillers such as fibrous fillers such as glass fibers, carbon fibers, whiskers, and metal fibers,
Platy fillers such as mica, tar, kaolinite, and granular fillers such as calcium carbonate, diatomaceous earth, alumina, and glass peas have been added to propylene resin for a long time, and are already widely used. It is used in

Among these various shapes of fillers, fibrous fillers have a particularly large reinforcing effect compared to other shapes of fillers, and glass fibers are particularly cheap and have good cost performance as reinforcing materials. Because of its excellent properties, glass fiber reinforced polypropylene is widely used in fields that require mechanical strength, rigidity, and heat deformation resistance.

However, glass fiber-reinforced polypropylene molded products have the disadvantage of large warpage deformation, which severely limits their use in applications requiring dimensional accuracy.

On the other hand, when plate-shaped fillers or granular fillers are used, the warping deformation is reduced, but when fibrous fillers are used ( However, polypropylene molded products reinforced with plate-shaped fillers such as mica powder and Merck exhibit good rigidity, so fibrous fillers and plate-shaped fillers are used in combination. Attempts have been made, for example, in JP-A-52-36141 and JP-A-54-1306.
No. 47, JP-A-55-16049, JP-A-Sho 5
Publication No. 5-21438 and Japanese Unexamined Patent Publication No. 55-4571 are also disclosed in publications.

However, in these publications, fR in the whole composition
This only applies to areas where the blending amount of the B-type filler is relatively small, and in particular, when the fibrous filler is glass fiber, only when the blending amount of the glass fiber is 10% by weight or less, there is relatively little warping and twisting. Glass fiber reinforced polypropylene (hereinafter referred to as FR-
It's called PP. ), the blending amount of glass fiber is 10
If the amount of glass fiber is less than 10% by weight, a sufficient reinforcing effect cannot necessarily be obtained, so in reality there is a great demand for FR-PP with a content of 10% by weight or more, but if the content of glass fiber exceeds 10% by weight, , when the molded product is made into a molded product, the warping deformation of the molded product suddenly increases. For this reason, conventional FR-P containing 10% by weight or more of glass fiber
P can only be used for molded products with shapes that are unlikely to warp or twist, and cannot be used for other purposes. Therefore, the blending amount of glass fiber is 10% by weight or more, and
FR- with less warping deformation of the molded product when made into a molded product
PP was strongly requested.

The present inventors conducted extensive research to solve the above-mentioned problems of FR-PP. As a result, even if the content of glass fiber is higher than 10% by weight in the whole composition, when a molded article is made by blending a specific amount of mica powder having a specific shape, the molded article 9. The present invention was completed by discovering that FR-PP can be obtained which can minimize warping deformation.

As is clear from the above description, the purpose of the present invention is to
It is an object of the present invention to provide a propylene resin composition capable of obtaining a molded article with significantly improved rigidity and warpage deformability while maintaining the excellent strength and heat deformation resistance of PP.

The present invention has the following configuration.

The total amount of the following components (a), (b), and (c) is 100% by weight, and the components (b) and (e) are blended with component (a) within their respective concentration ranges and obtained by melt-kneading. a composition in which the total amount of (b) + (c) is 25 to 55
In terms of weight, and (c)/χb) + (e) is 0.35
(a) Modified polypropylene modified with an unsaturated acid 45 to 75% by weight (b) Glass fiber 10 to 35% by weight (c
) 15-45% by weight of mica powder with an aspect ratio of 25 or more
.

The modified polypropylene modified with an unsaturated acid used in the present invention is a polypropylene obtained by melt-kneading polypropylene and an unsaturated acid in the presence of a radical generator.

As the unsaturated acid, unsaturated carboxylic acids or their anhydrides such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, citraconic acid, maleic anhydride, itaconic anhydride, etc. can be used. The polypropylene used as a raw material for modified polypropylene is not particularly limited, and may be a propylene homopolymer, propylene and ethylene, α-1 such as butene-1, hexene-1, octene-1, etc.
Examples include random copolymers or block copolymers with olefins.

Various known methods can be used to melt and cross-mix polypropylene with an unsaturated acid. After adding an organic peroxide such as peroxide and stirring and mixing with a Hensel mixer (trade name), etc., use an extruder to melt and knead at a temperature of 150C to 300C, preferably 180C.
A method of melt-kneading and extrusion at ~250C is simple and preferably used.

Furthermore, in the composition of the present invention, unmodified polypropylene may be mixed with modified polypropylene.

The glass fibers used in the present invention are usually commercially available glass chopped strands or glass rovings produced for resin reinforcement, and have an average fiber diameter of 5.
~20μ, and the average ft fiber length is preferably 0.5 van or more and 10 mm or less for chopped strand type.

Generally, in F R-P, glass fibers are cut at the stage of blending and melt-kneading with polypropylene and at the stage of molding, so the average fiber length of the glass fibers in the final molded product is Regardless of the average fiber diameter, the average fiber diameter is approximately in the order of 0.5 to 0.8.

Therefore, the average aspect ratio (fiber length/fiber diameter) in the final molded product is better when using glass fibers with a smaller average a-fiber diameter.
As a result, the reinforcement effect on mechanical strength, heat deformation resistance, etc. is large. However, on the other hand, molding anisotropy becomes noticeable, and the warp deformation of the molded product increases.

However, in the composition of the present invention, despite using glass fibers with a small average fiber diameter and large average fiber length, that is, a so-called high aspect ratio, the obtained molded product has good prevention of warpage deformation. Show your gender.

Furthermore, the mica powder used in the present invention has a ratio of the average diameter to the average thickness of the mica crystal plates, that is, an average aspect ratio of 2.
It is 5 or more, particularly preferably 45 or more.

Mica powder having an average aspect ratio of less than 25 is undesirable because it has poor warpage prevention properties.

The type of mica powder to be used is not particularly limited as long as it has an average aspect ratio of 25 or more, and can be selected from a wide range of biotite, scad mica, muscovite, phlogopite, and the like.

Furthermore, the mica powder used in the present invention may be one that has not been surface-treated, but it is also possible to use one that has been surface-treated with various surface-treating agents.

Next, in obtaining the composition of the present invention, the blending relationship between mica powder having an average aspect ratio of 25 or more and glass fiber will be described.

Now, when the total blending amount of modified polypropylene, glass fiber, and mica powder is expressed as 100 weight percent, the blending amount of glass fiber (wt%) and mica powder blending amount (wt%) are (b) and (c), respectively. Then lO≦(b)≦35 ■15≦(
c)≦45 00.35≦(c)/(
b)+(c)≦0.82 ■25≦(b)
+(c)≦55 It is necessary to blend glass fiber and mica powder into modified polypropylene so as to satisfy the following relational expression (2). When glass fiber and mica powder are used together as fillers, the tensile strength, flexural strength, Izot impact strength, and heat deformation resistance of molded products using such reinforced propylene resin compositions will vary depending on the amount of glass fiber used. Therefore, the regulation of 10≦(b)≦35 in equation (2) and the upper limit of 0.82 in equation (2) is necessary in order to achieve the low mechanical strength and high heat deformation resistance that are the characteristics of the present invention. This is a necessary condition. Next, 15 of formula ■
≦(c)≦45 and the lower limit value of 035 or more of the formula (■) are regulations regarding warpage prevention properties, and the relationships of the formula (2) and the formula (2) must be satisfied at the same time. That is, even if formula (2) is satisfied, if the amount of mica powder (c) blended is less than 155% by weight, the resulting molded product will not have sufficient warpage prevention properties.

In addition, the lower limit of formula (■) is a numerical value determined from the lower limits of formula (■) and formula (■), and the upper limit of formula (■) of 55 wt. This shows the upper limit of the amount of filler in the material.

The composition of the present invention can be manufactured by the following method. That is, for example, 1) predetermined amounts of each of modified polypropylene, mica powder, and glass fiber are placed in Hensel mixer (trade name) K, stirred and mixed, and then melt-kneaded and extruded at 150C using a single-screw or twin-screw extruder. 300C
Preferably, a method of melt-kneading and extrusion at 180C to 250C, 2) supplying the modified polypropylene from a normal raw material supply port, and providing an intermediate addition port so that other raw materials can be supplied to a position where the modified polypropylene is sufficiently melted. In the extruder, modified polypropylene and mica powder are supplied from a normal raw material supply port, and glass fiber is supplied from an intermediate addition port while melt-kneaded and extruded at the above temperature, 3) from a regular raw material supply port. This method involves supplying only modified polypropylene, supplying mica powder and glass fiber from an intermediate addition port, and melt-kneading and extruding at the above-mentioned temperature.

Further, various additives such as antioxidants, ultraviolet absorbers, antistatic agents, heat resistant agents, pigments, etc. can be used in combination with the composition of the present invention.

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

As a test method for evaluating the effects of the present invention, mechanical strength was measured by measuring tensile strength (based on JIS 7113) and bending strength (based on JIS K7203).
Rigidity is measured by bending modulus (based on JIs K7203), and impact strength is measured by Izot impact strength measurement (JIs K7203).
According to JIS K7110), the heat deformation resistance was determined by measuring the heat deformation temperature (load 18.6 Kq/ajl) (JIS K7
207), the warp deformability was measured by measuring the maximum warp deformation amount shown below.

Maximum amount of warping: 2mm thick, 150 each vertically and horizontally
A flat plate of size m and m was made by injection molding with the entire surface of one side as a film gate. The obtained flat plate was used as a test piece, and the test piece was heated at a temperature of 23C1RH50'l for 48 hours.
Time conditioning was performed. After that, the test piece is fixed at both ends of one side on a horizontal table, and the distance (warp 9) from the other end from the horizontal plane is measured and used as the amount of warp deformation. Since the amount of warp deformation differs depending on the position, we varied the position of one fixed side and measured the amount of warp deformation at the other end, and the maximum deformation was taken as the maximum warp deformation and expressed in units of shells. .

Example 1, Comparative Examples 1-2 Melt flow rate (load 2.1 at temperature 230C)
Discharge Ji of molten resin for 10 minutes when adding 6 kg
) 4.5 polypropylene homopolymer 98.15% by weight
Contains 1.0% by weight of maleic anhydride, 0.1% of 2.6-di-t-butylparazole, and 0% of calcium stearate.
1 weight 4.1. 0.055% by weight of a-bis(t-butylperoxyisobrobyl)benzene and 0.6% by weight of magnesium hydroxide were placed in a Hensel mixer (trade name), stirred and mixed for 3 minutes, and then mixed with A modified polypropylene pellet with a chloride rate of /D30 of 130 was obtained.

50% by weight of the modified polypropylene pellets and 30% by weight of mica powder with an aspect ratio of 70 (manufactured by Repco ■) were placed in a Hensel mixer (trade name), stirred and mixed for 1 minute, and then mixed using the twin-screw presser described above. , the mixture was supplied from a normal raw material supply port, and 20 weight sections of glass fiber (chopped strand, manufactured by Nippon Electric Glass, hereinafter referred to as glass flIa) with a strand diameter of 13μ and a length of 3m were put into a cylinder. Supplied while measuring from another supply port provided in the section,
Melt kneading temperature 25. The mixture was melt-kneaded, extruded, and pelletized using OC.

Further, as Comparative Examples 1 and 2, in Comparative Example 1, 80% by weight of modified polypropylene was supplied from the normal raw material supply port of the same extruder as in Example 1, and 20% by weight of glass fiber #a was provided in a part of the cylinder. The mixture was metered and fed from another feed port, and pelletized in the same manner as in Example 1. Comparative example 2 is modified polypropylene 50 bone part and mica powder with aspect ratio 70 5
0 weight ratio was mixed in the same manner as in Example 1, and using the twin-screw extrusion machine used in Example 1, the mixture was fed from a normal raw material supply port and melt-kneaded, extruded, and pelletized at a melt-kneading temperature of 250C. did. The pellets obtained on each side were put into an injection molding machine, and predetermined test pieces were molded at a resin temperature of 250 r and a mold temperature of 50 C, and were subjected to various evaluation tests.

Example 2, Comparative Example 3, Reference Example 1 As the glass fiber, #20 glass fiber (manufactured by Nippon Electric Glass, hereinafter referred to as glass fiber) with a strand diameter of 9μ and a length of 3 bags was used. The same amount of modified polypropylene was used as in Example 1, except that the same amount of modified polypropylene was used.As Comparative Example 3, the same amount of modified polypropylene was used as in Comparative Example 1, except that the glass fiber B20 bone used in Example 2 was used. The mixture was mixed in the same manner as in Example 1, and then melt-kneaded, extruded, and pelletized.

As Reference Example 1, instead of mica powder, talc powder (trade name manufactured by Matsuzai Sangyo ■) Ifilla-5000PJ) 30
The same amount of modified polypropylene and glass fibers were used as in Example 2 except that a bone parter was used, the modified polypropylene and talc powder were mixed in the same manner as in Example 1, and the mixture was melt-cross-extruded in the same manner as in Example 1. Pelletized. Using these pellets, prescribed test pieces were molded by injection molding in the same manner as in Example 1, and were subjected to various evaluation tests.

Examples 3 to 5, Comparative Examples 4 to 6 Example 3 uses mica powder with an aspect ratio of 55, Example 4 uses mica powder with an aspect ratio of 45, and Example 5 uses mica powder with an aspect ratio of 25. Similar to Example 1, using the same amounts of modified polypropylene and glass fibers, the modified polypropylene and mica powder were mixed in the same manner as in Example 1, and pelletized by melt cross-extrusion in the same manner as in Example 1.

Further, as Comparative Examples 4 to 6, Comparative Example 4 has an aspect ratio of 20
The same amount of modified polypropylene and glass fibers were used as in Example 2, except that Comparative Example 5 used mica powder with an aspect ratio of 15, and Comparative Example 6 used mica powder with an aspect ratio of 12. Mixed in the same manner as in Example 3,
Pelletization was carried out in the same manner as in Example 3 by melt mixing and extrusion. Using these pellets, test pieces were molded in the same manner as in Example 1 and subjected to various evaluation tests.

Examples 6 to 8, Comparative Examples 7 to 8 Example 6 was made of modified polypropylene 50% by weight, glass fiber b 25% by weight, mica powder with an aspect ratio of 70 25% by weight, and Example 7 was made of modified polypropylene 50% by weight. , glass tR fiber "b30 weight ratio, mica powder with aspect ratio 70 20% by weight, Example 8 modified polypropyref 54 bone part, glass fiber b30 weight ratio, mica ~ 8 with aspect ratio 70, Comparative example 7 Comparative Example 8 is modified polypropyref 60 bone part, glass fiber b 30% by weight, mica powder with an aspect ratio of 70 10% by weight.Comparative Example 8 is modified polypropyref 65
Bone department, glass fiber kneading extrusion pelletizing. Using these pellets, test pieces were molded in the same manner as in Example 1 and subjected to various evaluation tests.

The above results are summarized in Table 1.

As is clear from Table 1, in Example 1 using the composition of the present invention, the maximum amount of warping deformation was greatly improved compared to Comparative Example 1 in which only glass fiber a was blended. In Example 1, the bending elastic modulus was significantly lower than in Comparative Example 1 (compared to Comparative Example 1). It was found that the tensile strength, bending strength and heat distortion temperature were also improved.

Furthermore, when compared with Comparative Example 2, the tensile strength, bending strength, isot impact strength, and heat distortion temperature were improved.

Although Example 2 used glass fibers having a larger aspect ratio than Example 1, it exhibited good low warpage deformability similar to Example 1. The other mechanical strength, flexural modulus, Izot impact strength, and heat distortion temperature were superior to those of Example 1. Generally, when the fiber length of the glass fibers used is 0.5 or more, the smaller the average fiber diameter, the thicker the aspect ratio of the glass fibers in the final molded product. The mechanical strength, flexural modulus, and isot impact strength of the molded product will increase, but if only glass fiber is blended, the glass fiber and anisotropy will be significant, so the warping deformability will be large. This can be seen from the fact that Comparative Example 3 has greater warping deformability than Comparative Example 2. However, in Example 2, the warping deformability was greater than that of Example 1 even though glass fibers with a smaller diameter were used. It's surprising that it hasn't gotten any bigger.

Reference Example 1 contains talc powder, which is the same plate-shaped filler, instead of the mica powder in Example 2, but compared to Example 2, the improvement effect is inferior in all respects. .

In Examples 3 to 5 and Comparative Examples 4 to 6, the effect of the aspect ratio of the mica powder used was investigated, but compared to Comparative Examples 4 to 6, in which mica powder with an aspect ratio of 20 or less was blended, the warping was lower. It was found that the deformability and other properties were all excellent.

When the aspect ratio is 20 or less, as seen in Comparative Examples 4 to 6, as the aspect ratio increases, the warping deformability is improved to some extent, but it is not sufficient. A rapid improvement in warp deformability is observed within this range, and when the aspect ratio becomes 25 or more, the amount of warp deformation becomes significantly smaller. Also, Example 4
As can be seen, when the aspect ratio of the mica powder is 45 or more, the warp deformability is particularly good, and the warp deformability is approximately the same as Comparative Example 2, which contains only mica powder. Furthermore, it has been found that when the aspect ratio of the mica powder used is 25 or more, the flexural modulus and Izot impact strength are greatly improved.

In Examples 6 to 8 and Comparative Examples 7 to 8, the required ratio f (c) of mica powder to the total ratio t ((b) + (c)) of the glass fibers and mica powder used was investigated.
c)/(b)+(c) is outside the scope of the present invention 0, 25
Below, the warpage deformability of the obtained molded product is large, and a rapid improvement effect on the warp deformability is seen between 0.25 and 0.35, but it cannot be said to be sufficient yet. (c)/
It has been found that when (b)+(c) is 0.35 or more, particularly 0.4 or more, the warp deformability is sufficiently improved.

As described above, the molded product obtained using the composition of the present invention has significantly improved warp deformability, mechanical strength such as tensile strength and bending strength, rigidity, isot impact strength, and thermal strength. It was found that the molded product had excellent denaturation temperature, etc., and the remarkable effects of the present invention were confirmed.

that's all

Claims (4)

[Claims] (1) The total amount of the following components (a), (b), and (c) is 10
0% by weight, a composition obtained by blending components (b) and (c) with component (a) within their respective concentration ranges and melt-kneading, the total amount of (b) + (c) is 25-5
5% by weight, and (c)/(b)+(c) is 0.35 or more and 0.82 or less. (a) Modified polypropylene 45 modified with unsaturated acid. ~
75% by weight (b) 10-35% by weight of glass fiber (c) 15-45% by weight of mica powder having an aspect ratio of 25 or more. (2) The propylene resin composition according to claim (1), wherein the mica powder has an aspect ratio of 45 or more. (3) The average fiber diameter of the glass fibers is 11μ or less,
The propylene resin composition according to claim (1), which uses glass fibers having an average fiber length of 0.5 mm or more. (4) The propylene resin according to claim (1), which uses acrylic acid, methacrylic acid, maleic acid, fumaric acid, citraconic acid, maleic anhydride, itaconic anhydride, or two or more of these as the unsaturated acid. Composition.