JPH03239754A - Fiber-reinforced resin composition - Google Patents

Abstract

PURPOSE:To prepare the title compsn. allowing no phase separation to occur and giving a molded article with an improved impact resistance, improved wet dimensional stability, and lowered density by compounding specific polymer blends. CONSTITUTION:A polymer blend comprising a polyamide (A) (e.g. polyamide 6) and a polypropylene (B) in a wt. ratio of A to B of (75/25)-(35-65) is compounded with another polymer blend comprising a polypropylene (C), an unsatd. carboxylic acid-modified polypropylene (D) (e.g. a maleic anhydride- modified polypropylene), and a polyamide fiber (E) having an m.p. higher than that of the polyamide A (e.g. a polyamide 66 fiber) in a wt. ratio of the modified polypropylene D to the sum of the polypropylene C and polyamide E of (1/100)-(10/100) in such a ratio of the former polymer blend to the latter that the wt. ratio (A+E)/(B+C) is (65/35)-(35/65).

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a fiber-reinforced resin composition, and more specifically, a fiber-reinforced resin composition suitable for molding materials for hot flow stamping bottom shapes, injection molding, etc., and its effects. and an advantageous method for molding the resin composition.

[Conventional technology]

In general, polyamide resins have superior properties in terms of high heat resistance and mechanical strength compared to polyolefin resin materials. However, this polyamide resin is not necessarily satisfactory due to dimensional changes due to moisture absorption and poor moldability.

In order to solve this problem, conventionally, inorganic fillers such as glass fibers have been added. However, as a result, new problems have arisen, such as an increase in specific gravity and a significant decrease in impact resistance.

As another solution, attempts have been made to add a resin with good moldability and dimensional stability and modify it as a matrix material of an incompatible dispersion system. However, there are restrictions on the viscosity and amount of the added materials, and in order to increase the adhesive strength at the interface between the two materials, it was necessary to consider a compatibilizer that partially compatibilizes the two materials. However, when a large amount of compatibilizer is added, -11Q often causes a decrease in heat resistance, which has been a drawback of composite compositions.

Furthermore, even if a matrix is formed in this way, phase separation tends to occur if the molding conditions, for example the shear rate during molding is high or the molding temperature is not appropriate, and the desired physical properties are often not obtained. .

In order to avoid such problems, it is necessary to match the melt viscosities of both materials as much as possible, or the range of the composition ratio of both materials is inevitably restricted.

[Problem to be solved by the invention]

The present inventors have developed a polyamide-based resin composition that eliminates the problem of the conventional technology, suppresses phase separation, improves impact resistance, and achieves improved dimensional stability and lower specific gravity due to moisture absorption. He conducted extensive research to develop the product.

[Means to solve the problem]

As a result, polyamide fiber was selected as the material with the highest melting point among the materials that make up the matrix, and by adding it to the matrix, it macroscopically reinforced the already constituted matrix phase and achieved the purpose. It has been found that a resin composition having the following physical properties can be obtained. The present invention was completed based on this knowledge.

That is, in the present invention, (a) polyamide and (middle) polypropylene, (a)/(b) = 75/25 to 35/65 (
(weight ratio) and (c) polypropylene, (d) unsaturated carboxylic acid-modified polypropylene, and (e) polyamide fiber having a higher melting point than the polyamide, and (d) The modified polypropylene content is 10 in total of the above (c) and (e).
0 parts by weight to 1 to 10 parts by weight of the blend (B
), the ratio of the total amount of (a) polyamide and (e) polyamide fiber to the total amount of (b) polypropylene and (c) polypropylene ((a) + (e)) / ((b) + (c))
The present invention provides a fiber-reinforced resin composition having a ratio of 65/35 to 35/65 (weight ratio).

The composition of the present invention basically consists of a blend (A) and a blend (B).

Here, the blend (A) constitutes the basic matrix of the composition, and comprises (a) polyamide and (b) polypropylene (a)/(b) -75/25 to 35/
65 (weight ratio), preferably 70/30 to 40/60 (
(weight ratio).

It is also effective to add a compatibilizer to this blend (A) if necessary. In that case, 1 to 10 parts by weight, especially It is preferable to mix it in a proportion of 2 to 8 parts by weight.

As the polyamide (a) in the blend (A),
Various materials can be used, such as polyamide,
Polyamide 12. Polyamide 11. An appropriate material may be selected from a series of polyamides such as Boria ξ Doro 6. Note that this polyamide (a) is the polyamide (e) in the blend (B).
) It is necessary to select a material with a lower melting point than polyamide fiber. There is no particular restriction on the molecular weight of such (a) boriacid, but the molecular weight calculated from the solution intrinsic viscosity when measured in concentrated sulfuric acid at 23°C is 6.00.
0-120.000, especially 20.000-90.0
00 is preferred.

In addition, in the blend (A), the (b) polypropylene used together with the above (a) polyamide includes crystalline propylene homopolymer, propylene-ethylene random copolymer, propylene-butene-1 random copolymer, and block copolymers thereof. etc., and also mixtures thereof.

The melt flow rate (MF) of this (b) polypropylene
R) is not particularly limited, but is usually 0.1 to 230°C.
60 g/10 minutes, preferably in the range of 5 to 30 g/10 minutes.

In the above-mentioned blend (A), the compatibilizer that can be added if desired is the above-mentioned (a) boria straw and (b)
It is used for the purpose of improving adhesiveness at the interface of polypropylene and improving rigidity and impact resistance. Various kinds of compatibilizers can be used here, but ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), or a mixture thereof is preferable. .

In addition, (a) polyamide in blend (A) and (
c) The ratio with polypropylene is former/latter = 75/2
5 to 35/65 (weight ratio), preferably 70/30 to 4
The weight ratio is 0/60. Here, if the ratio of (a) polyamide is too large or too small, there will be a disadvantage that phase separation will occur and impact resistance will deteriorate.

The above blend (A) comprises (a) boria-based and (b)
It is obtained by adding and kneading polypropylene and, if necessary, a predetermined amount of a compatibilizer. This kneading may be carried out using an extruder or the like, but the kneading temperature at that time is (a)
It is desirable to set the temperature to the higher melting point of the polyamide and (b) the polypropylene (that is, the temperature at which both melt).

On the other hand, the blend (B) constituting the composition of the present invention together with the blend (A) includes (c) polypropylene, (d) unsaturated carboxylic acid-modified polypropylene, and (e
) It is made of polyamide fibers having a higher melting point than the above-mentioned polyamide. This blend (B) is a blend of polypropylene with polyamide fibers as an organic filler, and when forming a composition as a matrix material, a stable dispersion system is formed when each component is added together. Therefore, it is necessary to prepare the blend (B) separately from the blend (A).

The polypropylene (c) in the blend (B) is similar to the polypropylene that is a component of the blend (A), in addition to crystalline propylene homopolymer,
Examples include propylene-ethylene random copolymers, propylene-butene-1 random copolymers, and block copolymers thereof, and mixtures thereof. The polypropylene (c) may be of the same type as the polypropylene used as the component (b) or may be of a different type.

Various types of unsaturated carboxylic acid-modified polypropylene (d) can be used as the -component of the blend (B). Among these, graft-modified polypropylene with unsaturated carboxylic acids is preferred, and examples of the unsaturated carboxylic acids used for graft modification include acrylic acid, maleic acid, fumaric acid, itacone a, and 3,6-nindomethylene-1.

2.3.6-titrahydrosis-phthalic acid or anhydrides and esters thereof, alkyl agonomethacrylates such as 2-dimethylagonoethyl methacrylate, glycidyl methacrylate, etc., among which acrylic acid and maleic acid.

Maleic anhydride or 3,6-endomethylene-1,
The anhydride of 2,3,6-titrahydrosis-phthalic acid is preferred, especially maleic anhydride. In addition, these may be used individually or in mixture of 2 or more types.

Further, as radical generators used for graft modification, dikgolver oxide; benzoyl peroxide; di-t-butyl peroxide; 2,5-dimethyl-
2,5-di(t-butylperoxy>hexane; 2.5
Organic peroxides such as -dimethyl-2,5 di(t-butylperoxy)hexene-3; lauroyl peroxide; and t-butylperoxybenzoate are preferably used.

In producing the above-mentioned (d) unsaturated carboxylic acid-modified polypropylene, polypropylene (this is (b), (
It may be the same as or different from component c) polypropylene, but crystalline ones are preferred. ) is suspended or dissolved in a suitable solvent, the above-mentioned unsaturated carboxylic acid and radical generator are added thereto, and the mixture is heated and stirred. Alternatively, polypropylene, unsaturated carboxylic acid and radical generator are mixed in advance, and the mixture is mixed with an extruder, There is a method of melt-kneading using a Banbury mixer, a kneader, or the like. The blending ratio of each component may be appropriately selected depending on the situation, but usually 0.1 to 10 parts by weight of unsaturated carboxylic acid and 0 parts by weight of radical generator per 100 parts by weight of polypropylene.
．． It may be determined within a range of 0.01-10 parts by weight.

Further, as the polyamide fiber (e) in the blend (B), it is necessary to use one having a higher melting point than the polyamide (a). The reason why polyamide fibers having a higher melting point than the polyamide of component (a) is used as the polyamide fiber (e) is that the blend (A) and blend (B) are melt-kneaded or further molded. This is because melting the other components while keeping the polyamide fibers in a fibrous form without melting them is effective in increasing the strength of the resulting molded product. here,(
e) Polyamide fibers include polyamide 6, polyamide 12, polyamide 11. Among polyamide 66,
Polyamides having a higher melting point than the polyamide used as component (a) are preferably used. The length and diameter of the fibers can be selected as appropriate, but generally the length is 6 to 25 mm and the diameter is 8 to 25 mm.
It may be determined within a range of 20 μm.

(d) Unsaturated carboxylic acid-modified polypropylene in blend (B) is added to improve the adhesion at the interface between (c) polypropylene and (e) polyamide fibers, and its content is equal to the above (c). ) Polypropylene and (e) 1 per 100 parts by weight of polyamide fibers in total
~10 parts by weight, preferably 1.5 to 8 parts by weight. Here, if the content of (d) unsaturated carboxylic acid-modified polypropylene is too small, the adhesion at the interface between (c) polypropylene and (e) polyamide fibers will be insufficient, and if it is too large, the resulting composition This results in a disadvantage that the mechanical properties of the material are deteriorated.

The resin composition of the present invention is obtained by blending the above-mentioned blend (A) and blend (B), and the blending ratio of both blends (A) and (B) is as follows: (a) polyamide and (e) the ratio of the total amount of polyamide fibers to the total amount of (b) polypropylene and (c) polypropylene (
(a) + (e) ) / ((b) + (c) )
is 65/35 to 35/65 (weight ratio), preferably 6
It is 2/38 to 37/63 (weight ratio). This ratio is 6
If it is larger than 5/35, there is a problem that (a) polyamide will phase separate from (b) polypropylene and (c) polypropylene, and if it is smaller than 35/65, it will phase separate from (b) polypropylene and (c) polypropylene. (a
) The disadvantage is that the polyamide undergoes phase separation.

In order to obtain the resin composition of the present invention, as described above, it is necessary to prepare the blends (A) and (B) in advance and mix them in a predetermined ratio.

In addition, in order to produce this resin composition, the above blends (A) and (B) are blended in the above ratio, and
(e) It is preferable to knead at a temperature below the melting point of the polyamide fiber, particularly at a temperature above the melting point of (a) the polyamide and (
e) Most preferably kneading is carried out at a temperature below the melting point of the polyamide fibers.

There are various methods for molding the resin composition of the present invention, and there are no particular limitations. It is desirable to perform processing such as shaping. Specifically, blends (A) and (B)
are tri-blended in the above-mentioned ratio, put into a molding machine, melted, and molded.

The reason for preparing the blends (A) and (B) in advance and blending them in a predetermined ratio to prepare the resin composition of the present invention is as follows. That is, for example, (e) the polyamide fiber as the reinforcing fiber is polyamide 66, and the (a) polyamide having either a groove phase or an island phase is polyamide 6, and (e) the melting point of the polyamide fiber is (a) polyamide fiber. If it is higher than the melting point, each component (
That is, the above-mentioned components (a) to (e)) are mixed with polyamide 6
Even if they are simultaneously blended at a melting temperature that does not exceed the melting point of polyamide 6 and polypropylene, the dispersion of polyamide 6 and polypropylene is unlikely to collapse.

However, most of the unsaturated carboxylic acid-modified polypropylene (d) added for the purpose of adhering the surface of polyamide fibers reacts with the active hydrogen of the terminal amide group of polyamide 6, which is melted first. Also, more (d) unsaturated carboxylic acid modified polypropylene must be added, and the addition of such modified resin is
This is undesirable because it causes a decrease in the mechanical properties of the m-acid. Therefore, it is desirable to prepare the blend (A) and the blend (B) in advance as preliminary compound materials, and then blend them again by tri-blending or pelletizing, that is, a sequential blending method.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 Polyamide 6 (molecular weight 30.000 as measured by solution viscosity method using sulfuric acid as a solvent) 65% by weight and polypropylene (MFR at 230°C 10 g/10 min) 3
A mixture consisting of 5% by weight and 5 parts by weight of EAA (based on 100 parts by weight of polyamide 6 and polypropylene) was kneaded at 250°C in a single screw extruder. The obtained kneaded product was designated as a blend (A).

On the other hand, 65% by weight of the same polypropylene as above.

Polyamide 66 fiber (6 strand length, diameter 13μm)
35% by weight and maleic anhydride-modified polypropylene [maleic anhydride grafting rate o, 03% (mole of maleic anhydride groups/mole of methylene groups).

MFR30g/10min at 230°C] 5 parts by weight (
A total of 100 of the above polypropylene and Boria ξ Doro 6 fibers
parts by weight) was kneaded at 230°C using the same extruder as above.

The obtained kneaded product was designated as a blend (B).

Next, the blends (A) and (B) were weighed so that the composition after mixing was 50150 (weight ratio), introduced into a single-screw extruder, and pelletized again at 230°C. It became. Note that the composition after mixing the blends (A) and (B) refers to the composition of the polyamide in the mixture (composition or pellets) obtained by mixing the blends (A) and (B). It refers to the ratio of the total amount of polyamide fibers to polypropylene, (polyamide fibers)/polypropylene.

Next, the obtained pellet was shaped into a bottom shape using an injection molding machine, and a test piece was cut out from it, and this test piece was used for JI.
Mechanical strength was measured according to the measurement method specified in SK6758. In addition, heat deformation resistance and shrinkage rate were measured. The results are shown in Table 1.

Examples 2 to 6 and Comparative Examples 1 to 2 In Example 1, blends (A) and (B) were prepared by blending each component in the proportions shown in Table 1, and these blends (A) Test pieces were prepared and various physical properties were measured in the same manner as in Example 1, except that ) and (B) were introduced into a single-screw extruder in the proportions shown in Table 1. The results are shown in Table 1.

The blending ratio of EAA in the blend (A) is as follows:
Everything is the same as in Example 1.

Comparative Example 3 Example 1, except that without preparing blends (A) and (B), the components were introduced directly into the axle extruder at an extrusion temperature of 260"C in the proportions shown in Table 1. Test pieces were prepared and various physical properties were measured in the same manner as above.The results are shown in Table 1.The polyamide fibers were dissolved and could not be observed, and the impact resistance was poor.

Comparative Example 4 The same operation as in Example 1 was performed except that the polyamide fibers constituting the blend (B) were changed from polyamide 6 to polyamide 6. The results are shown in Table 1.

As can be seen from Table 1, when polyamide fibers identical to those of the polyamide of blend (A), that is, polyamide fibers having the same melting point, are used, the impact resistance of the molded article is significantly reduced. Further, when the cross section of the test piece was observed, it was found that no boria fibers were observed, and the dispersed particle size of polypropylene, which could be observed as an island phase, was as large as 1100 a, indicating poor dispersibility.

(The following is a blank space) [Effects of the Invention] According to the present invention, there is no phase separation, the impact resistance is improved,
In addition, a fiber-reinforced resin composition, which is a material for molded products, can be obtained which has improved dimensional stability due to moisture absorption and a lower specific gravity.

Since this fiber-reinforced resin composition has the above-mentioned properties, it is expected to be effectively used as a molding material for hot flow stamping molding, injection molding, and the like.

Claims (5)

[Claims] (1) (a) polyamide and (b) polypropylene,
(a)/(b) = 75/25 to 35/65 (weight ratio) blend (A) and (c) polypropylene, (d) unsaturated carboxylic acid-modified polypropylene, and (e) (d) the modified polypropylene content is 10 in total of (c) and (e);
0 parts by weight to 1 to 10 parts by weight of the blend (B
), the ratio of the total amount of (a) polyamide and (e) polyamide fiber to the total amount of (b) polypropylene and (c) polypropylene ((a) + (e)) / ((b) + (c)) but,
A fiber-reinforced resin composition blended in a weight ratio of 65/35 to 35/65. (2) The blend (A) contains a compatibilizing agent in the blend (A).
The fiber-reinforced resin composition according to claim 1, wherein the fiber-reinforced resin composition is contained in a proportion of 1 to 10 parts by weight based on 100 parts by weight of A). (3) Blend (A) of claim 1 or 2 and claim 1
Blend (B) of ((a)+(e))/((b)
) + (c)) is blended so that it is 65/35 to 35/65 (weight ratio), and (e) is kneaded at a temperature below the melting point of the polyamide fiber. How things are manufactured. (4) The fiber reinforced resin composition of claim 1 or 2, (a)
A method for molding a resin composition, comprising processing and molding at a temperature higher than the melting point of polyamide and lower than the melting point of (e) polyamide fibers. (5) The fiber reinforced resin composition obtained in claim 3 (a
A method for molding a resin composition, which comprises processing and molding at a temperature that is above the melting point of the polyamide and (e) below the melting point of the polyamide fiber.